diff --git a/mkdocs.yml b/mkdocs.yml
index fbdf9ab833..60f0353ac2 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -48,6 +48,7 @@ nav:
         - MEG file formats: 99-appendices/06-meg-file-formats.md
         - MEG systems: 99-appendices/07-meg-systems.md
         - Coordinate systems: 99-appendices/08-coordinate-systems.md
+        - qMRI: 99-appendices/09-qmri.md
       - Changelog: CHANGES.md
     - The BIDS Starter Kit:
       - GitHub repository: https://github.com/bids-standard/bids-starter-kit
diff --git a/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md b/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md
index 625187c6a0..8721913ad8 100644
--- a/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md
+++ b/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md
@@ -37,6 +37,17 @@ by Ben Inglis:
 | SequenceName                | RECOMMENDED. Manufacturer’s designation of the sequence name. Corresponds to DICOM Tag 0018, 0024 `Sequence Name`.                                                                                                                                                             |
 | PulseSequenceDetails        | RECOMMENDED. Information beyond pulse sequence type that identifies the specific pulse sequence used (i.e. "Standard Siemens Sequence distributed with the VB17 software," "Siemens WIP ### version #.##," or "Sequence written by X using a version compiled on MM/DD/YYYY"). |
 | NonlinearGradientCorrection | RECOMMENDED. Boolean stating if the image saved has been corrected for gradient nonlinearities by the scanner sequence.                                                                                                                                                        |
+| MTState           | RECOMMENDED. Boolean value (`true` or `false`), specifying whether the magnetization transfer pulse is applied. This parameter is REQUIRED by all the anatomical images grouped by `MTR`, `MTS` and `MPM` suffixes. This field originally corresponds to DICOM tag 0018, 9020 `Magnetization Transfer`. |
+| MTOffsetFrequency | RECOMMENDED. The frequency offset of the magnetization transfer pulse with respect to the central H1 Larmor frequency in Hertz (Hz).                                                                                                                                                                    |
+| MTPulseBandwidth  | RECOMMENDED. The excitation bandwidth of the magnetization transfer pulse in Hertz (Hz).                                                                                                                                                                                                                |
+| MTNumberOfPulses  | RECOMMENDED. Number of magnetization transfer RF pulses applied before the readout.                                                                                                                                                                                                                     |
+| MTPulseShape      | RECOMMENDED. Shape of the magnetization transfer RF pulse waveform. Accepted values: `HARD`, `GAUSSIAN`, `GAUSSHANN` (gaussian pulse with Hanning window), `SINC`, `SINCHANN` (sinc pulse with Hanning window), `SINCGAUSS` (sinc pulse with Gaussian window), `FERMI`.                                 |
+| MTPulseDuration   | RECOMMENDED. Duration of the magnetization transfer RF pulse in seconds.                                                                                                                                                                                                                                |
+| SpoilingState            | RECOMMENDED. Boolean value (`true` or `false`), specifying whether the pulse sequence uses any type of spoiling stratey to suppress transverse magnetization remaining after the readout. |
+| SpoilingType             | RECOMMENDED. Specifies which spoiling method(s) are used by a spoiled sequence. Accepted values: `RF`, `GRADIENT` or `COMBINED`.                                                          |
+| SpoilingRFPhaseIncrement | RECOMMENDED. The amount of incrementation described in degrees, which is applied to the phase of the excitation pulse at each TR period for achieving RF spoiling.                        |
+| SpoilingGradientMoment   | RECOMMENDED. Zeroth moment of the spoiler gradient lobe in millitesla times second per meter (mT.s/m).                                                                                     |
+| SpoilingGradientDuration | RECOMMENDED. The duration of the spoiler gradient lobe in seconds. The duration of a trapezoidal lobe is defined as the summation of ramp-up and plateu times.                            |
 
 #### In-Plane Spatial Encoding
 
@@ -114,29 +125,253 @@ Template:
 ```Text
 sub-<label>/[ses-<label>/]
     anat/
-        sub-<label>[_ses-<label>][_acq-<label>][_ce-<label>][_rec-<label>][_run-<index>]_<modality_label>.nii[.gz]
-        sub-<label>[_ses-<label>][_acq-<label>][_ce-<label>][_rec-<label>][_run-<index>][_mod-<label>]_defacemask.nii[.gz]
-```
-
-Anatomical (structural) data acquired for that participant. Currently supported
-modalities include:
-
-| Name               | `modality_label` | Description                                                                                                                                       |
-| ---------------------------------------------------------------------- | --------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| T1 weighted        | T1w              |                                                                                                                                                   |
-| T2 weighted        | T2w              |                                                                                                                                                   |
-| T1 Rho map         | T1rho            | Quantitative T1rho brain imaging <br> <https://www.ncbi.nlm.nih.gov/pubmed/24474423> <br> <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4346383/> |
-| T1 map             | T1map            | quantitative T1 map                                                                                                                               |
-| T2 map             | T2map            | quantitative T2 map                                                                                                                               |
-| T2\*               | T2star           | High resolution T2\* image                                                                                                                        |
-| FLAIR              | FLAIR            |                                                                                                                                                   |
-| FLASH              | FLASH            |                                                                                                                                                   |
-| Proton density     | PD               |                                                                                                                                                   |
-| Proton density map | PDmap            |                                                                                                                                                   |
-| Combined PD/T2     | PDT2             |                                                                                                                                                   |
-| Inplane T1         | inplaneT1        | T1-weighted anatomical image matched to functional acquisition                                                                                    |
-| Inplane T2         | inplaneT2        | T2-weighted anatomical image matched to functional acquisition                                                                                    |
-| Angiography        | angio            |                                                                                                                                                   |
+        sub-<label>[_ses-<label>][_acq-<label>][_part-<label>][_echo-<index>][_fa-<index>][_inv-<index>][_mt-<on/off>][_ce-<label>][_rec-<label>][_run-<index>]_<suffix>.nii[.gz]
+        sub-<label>[_ses-<label>][_acq-<label>][_part-<label>][_echo-<index>][_fa-<index>][_inv-<index>][_mt-<on/off>][_ce-<label>][_rec-<label>][_run-<index>][_mod-<suffix>]_defacemask.nii[.gz]
+```
+
+The term anatomical imaging data pertains to a broad range of MRI applications that provide structural 
+information about (brain) anatomy, but differ by the nature of the data they contain. Anatomical
+(structural) data for a participant may refer to three types of data:
+1. a single image with specific weighting on an arbitrary scale (e.g. a 3D high resolution T1-weighted image).
+This type is most commonly used in neuroimaging applications.
+2. a group of images acquired within a single protocol for the purpose of improving contrast 
+characteristics (e.g., a set of multi-echo anatomical GRE images) or calculating quantitative maps
+(e.g. four 3D volumes provided as an input to an MP2RAGE calculation). 
+3. a quantitative map of which the intensities are put on an absolute scales (e.g., seconds for a T1 map).
+These images are generally produced by some mathematical operation on images from class 2.
+
+#### Conventional structural acquisitions
+
+Anatomical images of this type typically refer to a volumetric high-resolution 
+dataset, representing the measured MRI signal in an arbitrary scale of "gray
+shades". Contrast factor of these grayscale images depends on the relative contribution
+of inherent tissue parameters (e.g. `T1`, `T2` and `PD`) to the measured signal. 
+
+Contribution weights of these parameters are determined by the type of acquisition
+sequence (e.g. `spin-` or `gradient-echo`) and the setting of various parameters
+(e.g. `Repetition Time`, `Echo Time`, `Inversion Time` and `Flip Angle`). For 
+example, in a spoiled gradient-echo scan, keeping the repetition and the echo time 
+short with a relatively large flip angle increases the contribution of `T1` effects
+to the image contrast, yielding a primarily T1-weighted image.
+
+#### Grouped scan collections for contrast improvement or quantitative map calculation
+
+A group of anatomical scans may be collected to enhance certain contrast features,
+such as to calculate a weighted average of multi-echo gradient echo (`MEGRE`) images,
+which is known to improve segmentation algorithm outputs.
+
+Quantitative MRI (qMRI) methods mathematically characterize the signal changes observed
+in a collection of parametrically altered scans under certain biophysical model assumptions.
+These `grouped scan collections` can then be processed to derive a `qMRI map`, representing
+anatomical features in a physically meaningful parameter range.
+
+In both cases, the contrast characteristics change with varying acquisition parameters across
+`grouped scan collections`. Therefore, it is not tenable to name all the members
+of a `grouped scan collection` with one conventional MRI suffix label (e.g., `T1w`)
+or any other label that implies interchangeability among its instances. 
+
+To circumvent this problem, the `_<suffix>` entity is adaptively used according 
+to the intended application of anatomical imaging data. For conventional MRI 
+applications, the suffixes will correspond to common anatomical contrasts `T1w`,
+`T2w`, `T2starw` etc. For groups of scans acquired for contrast improvement or 
+qMRI processing, the `_<suffix>` indicates the collection that the scans belong to.
+
+#### The `_suffix` entity
+
+To ensure an comprehensible, human readable directory that contains anatomical 
+imaging data, the `_<suffix>` entity can be used in one of three ways:
+
+1. Conventional MRI suffixes
+2. Grouping suffixes
+3. Quantitative MRI (qMRI) map suffixes
+
+This distinction was added to the specification on acceptance of the BEP001 
+proposal in version `1.4.0`. However, as a result, some  suffixes that were introduced
+into BIDS at an earlier point time are inconsistent with this typology: for example 
+because they are linked to a readout-sequence rather than a contrast, or because 
+they don't clearly distinguish between a quantitative map or a contrast-weighted 
+image. These `legacy`-suffixes are no longer recommended but remain part of the 
+specification in order to maintain backwards compatability with previous versions 
+of the specification.
+
+These can be found in the [legacy suffixes](#legacy-suffixes) subsection.
+
+Previous versions of the specification used the term `modality_label` instead of 
+`_suffix` to represent this entity. The change in term was introduced in version 
+`1.4.0.` to accodomate a broad definition of anatomical imaging applications.
+
+##### Conventional MRI suffixes
+
+**Purpose:**
+
+Denotes the type of the predominant contrast conveyed by an individual file of
+a conventional anatomical image.
+One of the `_<suffix>` entries listed in the table below
+is REQUIRED (with additional entities where applicable) to provide a self-explanatory 
+file name.
+
+A change to the specification is REQUIRED to expand or to modify the following table.
+
+| Name                                       | _suffix | _suffix type | Description                                                                                                                                                                                                                     |
+|--------------------------------------------|---------|--------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| T1 weighted images                         | T1w     | Conventional | Denotes images with predominant T1 contribution.                                                                                                                                                                                |
+| T2 weighted images                         | T2w     | Conventional | Denotes images with predominant T2 contribution.                                                                                                                                                                                |
+| Proton density weighted images             | PDw     | Conventional | Denotes images with predominant proton density (PD) contribution.                                                                                                                                                               |
+| T2 star weighted images                    | T2starw | Conventional | Denotes images with predominant T2\* contribution. Please note that this suffix is not a surrogate for `T2starmap`. |
+| Fluid Attenuated Inversion Recovery Images | FLAIR   | Conventional | Denotes images with predominant T2 contribution (a.k.a T2-FLAIR), in which signal from fluids (e.g. CSF) is nulled out by adjusting inversion time, coupled with notably long repetition and echo times.              |
+| Inplane T1                                 | inplaneT1 | Conventional | T1-weighted anatomical image matched to functional acquisition                                                           |
+| Inplane T2                                 | inplaneT2 | Conventional | T2-weighted anatomical image matched to functional acquisition                                                           |
+| PDw and T2w images obtained using dual-echo FSE           | PDT2| Conventional | PDw and T2w images acquired using a dual-echo FSE sequence through view sharing process [(Johnson et al. 1994)](http://www.ajnr.org/content/15/4/667.short).                                                           | 
+
+Example use for conventional **T1 weighted images**:
+
+```Text
+sub-01_run-1_T1w.nii.gz
+sub-01_run-1_T1w.json
+sub-01_run-2_T1w.nii.gz
+sub-01_run-2_T1w.json
+```
+
+The `run` entity in the example above denotes the index of the acquisition
+repeated with the identical scan parameters (e.g., to achieve a higher SNR by averaging the scans together).
+Note that changing parameters between multiple acquisitions of the same sequence
+creates a different use case: **grouped scan collections**. For more information see
+the [grouping suffixes](#grouping-suffixes) subsection.
+
+**Important:**
+
+If an anatomical image is defaced for anonymization, one MAY provide
+the binary mask that was used to remove facial features. In the specific case of
+naming this binary mask, the `_<suffix>` entity is replaced by `_<defacemask>` entry.
+Therefore, to contain the original `_<suffix>` entry, the OPTIONAL `mod-<suffix>`
+entity is used. For example, deface mask image belonging to a **T1 weighted image** is named as follows:
+
+```
+sub-01_mod-T1w_defacemask.nii.gz
+sub-01_mod-T1w_defacemask.json
+```
+##### Grouping suffixes
+
+**Purpose:**
+
+Files that belong to a **grouped scan collection** are part of a single scan
+protocol that acquires multiple images with  similar acquisition parameters
+that are systematically altered. Grouped scan collections are intended to
+a) increase contrast by combining multiple similar images (e.g., a multi-echo
+GRE), or b) to estimate physical parameters on an absolute scale, within a
+qMRI analysis framework (e.g., a T1-map using a MP2RAGE-protocol). The
+quantitative maps that are output from these calculations (e.g., `T1map`,
+`T2map` etc) are described in the [qMRI map suffixes](#qmri-map-suffixes)
+section below.  A change to the specification is REQUIRED to expand or to
+modify the following table.
+
+| Name                                       | Suffix  | Type     | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|--------------------------------------------|---------|----------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Variable flip angle                        | VFA     | Grouping | The VFA method involves at least two spoiled gradient echo (SPGR) of steady-state free precession (SSFP) images acquired at different flip angles. Depending on the provided metadata fields and the sequence type, data may be eligible for DESPOT1, DESPOT2 and their variants ([Deoni et al. 2005](https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.20314)). Please visit the [qMRI appendix](#prioritylevels) for details. _Associated output suffixes_: T1map, T2map, R1map, R2map |
+| Inversion recovery (for T1 mapping)        | IRT1    | Grouping | The IRT1 method involves multiple inversion recovery spin-echo images acquired at different inversion times ([Barral et al. 2010](https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.22497)). _Associated output suffixes_: T1map, R1map                                                                                                                                                                                                                                                                                                                    |
+| Magnetization prepared two gradient echoes | MP2RAGE | Grouping | The MP2RAGE method is a special protocol that collects several images at different flip angles and inversion times to create a parametric T1map by combining the magnitude and phase images ([Marques et al. 2010](https://www.sciencedirect.com/science/article/pii/S1053811909010738?casa_token=u_CYBx4hi7IAAAAA:3w0cMTyU5jA1BdFs0s5oVcQeqF2tZho0iJ9d4N1kExfaX27v9-JnWacF6mbEp_lMKZ64CvoTl8k)). _Associated output suffixes_: T1map, R1map, UNIT1                                                                                                                                                                                                                 |
+| Multi-echo spin echo                       | MESE    | Grouping | The MESE method involves multiple spin echo images acquired at different echo times and is primarily used for T2 mapping. _Associated output suffixes_: T2map, R2map, MWFmap                                                                                                                                                                                                                                                                                                                         |
+| Multi-echo gradient echo                   | MEGRE   | Grouping | Anatomical gradient echo images acquired at different echo times. _Associated output suffixes_: T2starmap, R2starmap                                                                                                                                                                                                                                                                                                                                             |
+| Magnetization transfer ratio               | MTR     | Grouping | Anatomical images for calculating a semi-quantitative magnetization transfer ratio map. _Associated output suffixes_: MTRmap                                                                                                                                                                                                                                                                                                                                                                                 |
+| Magnetization transfer saturation          | MTS     | Grouping | Anatomical images for calculating a semi-quantitative magnetization transfer saturation index map. The MTS method involves three sets of anatomical images that differ in terms of application of a magnetization transfer RF pulse (MTon or MToff) and flip angle ([Helms et al. 2008](https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.21732)). _Associated output suffixes_: T1map, MTsat                                                                                                                                                                                               |
+| Multi-parametric mapping                   | MPM     | Grouping | Anatomical images for multiparametric mapping (a.k.a hMRI). The MPM approaches involves the acquisition of highly-similar anatomical images that differ in terms of application of a magnetization transfer RF pulse (MTon or MToff), flip angle and (optionally) echo time and magnitue/phase parts ([Weiskopf et al. 2013](https://www.frontiersin.org/articles/10.3389/fnins.2013.00095/full)). See [here](https://owncloud.gwdg.de/index.php/s/iv2TOQwGy4FGDDZ) for suggested MPM acquisition protocols.,_Associated output suffixes_:R1map, R2starmap, MTsat, PDmap, T1map, T2starmap                                               |
+
+For example:
+
+```Text
+sub-01_fa-1_VFA.nii.gz
+sub-01_fa-1_VFA.json
+sub-01_fa-2_VFA.nii.gz
+sub-01_fa-2_VFA.json
+```
+
+Please see the [entity table appendix]() for the REQUIRED and OPTIONAL entities
+for each `grouping suffix`. 
+
+Note that every image in a **grouped scan collection** has the same `_<suffix>` 
+as they are supposed to be used together. Although the acquisitions will have
+many identical acquisition parameters, only one-to-one-mapping is allowed
+between a `.json`-sidecar file and an image in a grouped scan collection.
+This follows directly from the
+[inheritance principles of BIDS](../02-common-principles.md#the-inheritance-principle):
+parameter values that are identical across a set of grouped scans will still
+have to be stored separately in each `.json`-sidecar file.
+
+##### qMRI map suffixes 
+
+**Function:**
+
+Denotes the parameter contained within an individual file of a
+quantitative parametric image.
+
+Changes to the specification are REQUIRED to
+expand or to modify the following table.
+
+| Name                                                   | _suffix   | _suffix type | Description                                                                                                                                                                                                                                                                          |
+|--------------------------------------------------------|-----------|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Longitudinal relaxation time map                       | T1map     | Parametric   | In seconds (s). T1 maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `VFA`, `IRT1`, `MP2RAGE`, `MTS`,`MPM`. See [this interactive book on T1 mapping](https://qmrlab.org/t1_book/intro) for further reading on T1-mapping.  |
+| True transverse relaxation time map                    | T2map     | Parametric   | In seconds (s). T2 maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MESE`, `MPM`                                                                                                                                       |
+| Observed transverse relaxation time map                | T2starmap | Parametric   | In seconds (s). T2\* maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MEGRE`, `MPM`                                                                                                                                     |
+| Longitudinal relaxation rate map                       | R1map     | Parametric   | In seconds-1 (1/s). R1 maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `VFA`, `IRT1`, `MP2RAGE`, `MTS`, `MPM`                                                                                                           |
+| True transverse relaxation rate map                    | R2map     | Parametric   | In seconds-1 (1/s). R2 maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MESE`, `MPM`                                                                                                                                  |
+| Observed transverse relaxation rate map                | R2starmap | Parametric   | In seconds-1 (1/s). R2\* maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_`MEGRE`, `MPM`                                                                                                                                 |
+| Proton density map                                     | PDmap     | Parametric   | In arbitrary units (a.u.). PD maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MPM`                                                                                                                                    |
+| Magnetization transfer ratio map                       | MTRmap    | Parametric   | In percentage (%). MTR maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MTR`                                                                                                                                           |
+| Magnetization transfer saturation index map            | MTsat     | Parametric   | In arbitrary units (a.u.). MTsat maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MTS`, `MPM`                                                                                                                          |
+| Homogeneous (flat) T1-weighted image by MP2RAGE                 | UNIT1     | Parametric   | In arbitrary units (a.u.). UNIT1 images are REQUIRED to use this suffix irrespective of the method they are related to. Note that although this image is T1-weighted, regions without MR signal will contain white salt-and-pepper noise that most segmentation algorithms will fail on. Therefore, it is important to dissociate it from from `_T1w` _Can be generated from:_ `MP2RAGE`                                                                                                                             |
+| Longitudinal relaxation in rotating frame (T1 rho) map | T1rho     | Parametric   | In seconds (s). T1-rho maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ N/A                                                                                                                                             |
+| Myelin water fraction map                              | MWFmap    | Parametric   | In percentage (%). MWF maps are REQUIRED to use this suffix irrespective of the method they are related to. _Can be generated from:_ `MESE`                                                                                                                                          |
+| Combined PD/T2 map                                     | PDT2map   | Parametric   | In arbitrary units (a.u.). Combined PD/T2 maps are REQUIRED to use this suffix irrespective of the method they are related to. N/A                                                                                                                                                   |
+| RF transmit field map                                  | TB1map | Parametric   | In percent units (p.u.). Radio frequency (RF) transmit field maps are REQUIRED to use this suffix irrespective of the method they are related to. Please see the [qMRI appendix](../99-appendices/09-qmri.md) for associated inputs and further details                                                                     |
+| RF receive sensitivity map                                  | RB1map | Parametric   | In percent units (p.u.). Radio frequency (RF) receive sensitivity maps are REQUIRED to use this suffix irrespective of the method they are related to. Please see the [qMRI appendix](../99-appendices/09-qmri.md) for associated inputs and further details                                                                     |
+| Observed signal amplitude map                                | S0map | Parametric   | In arbitrary units (a.u.). For a multi-echo sequence, S0 maps index the baseline signal before exponential (T2\*) signal decay. In other words: the exponential of the intercept for a linear decay model across log-transformed echos. For more information, please see, for example, [the tedana documentation](https://tedana.readthedocs.io/en/latest/approach.html#monoexponential-decay-model-fit). S0 maps are REQUIRED to use this suffix irrespective of the method they are related to. _Associated suffixes:_ T2starmap.       |
+| Quantitative susceptibility map (QSM)                   | Chimap | Parametric   | In parts per million (ppm). QSM allows for determining the underlying magnetic susceptibility of tissue (Chi).  Chi-maps are usually constructed from the phase images of GRE sequences. Chi-maps are quantitative and are reconstructed by solving the magnetic field to susceptibility source inverse problem ([Wang & Liu, 2014](https://onlinelibrary.wiley.com/doi/10.1002/mrm.25358)). |
+
+Quantitative maps can be obtained right off the scanner or by processing files
+belonging to a `grouped scan collection`. Regardless of the method they are
+obtained by, one of the `_suffix` entries listed in the table above is REQUIRED
+for a proper naming. For example:
+
+```Text
+sub-01_T1map.nii.gz
+sub-01_T1map.json
+```
+**Important:**
+
+Quantitative unit of the parameter contained by a quantitative map MUST comply
+with the unit description provided for its respective `_suffix` entry.
+For example, a T1 map in milliseconds unit (ms) is not valid, given that the
+description of the `T1map` suffix requires the parameter to be in seconds (s).
+
+#### The `part` entity
+
+This entity is used to indicate which component of the complex representation
+of the MRI signal is represented in voxel data. The `part-<label>` key/value pair is
+associated with the DICOM tag
+[0008,9208](https://dicom.innolitics.com/ciods/enhanced-mr-image/enhanced-mr-image/00089208).
+Allowed label values for this entity are `phase`, `mag`, `real` and `imag`,
+which are typically used in `mag/phase` or `real/imag` pairs. For example:
+
+```
+sub-01_part-mag_T1w.nii.gz 
+sub-01_part-mag_T1w.json
+sub-01_part-phase_T1w.nii.gz 
+sub-01_part-phase_T1w.json
+```
+
+Phase images MAY be in radians or in arbitrary units. The sidecar JSON file MUST 
+include the units of the `phase` image. The possible options are:  `radians` or 
+`a.u.` for grayscale images. For example: 
+
+sub-01_part-phase.json
+```
+{
+   "Units": "radians"
+}
+```
+
+If the `part` key/value pair is absent from a filename, the image SHOULD be a 
+magnitude image.
 
 #### The `run` entity
 
@@ -161,6 +396,75 @@ can also be used to make that distinction. At what level of detail to make the
 distinction (e.g. just between RARE and FLASH, or between RARE, FLASH, and
 FLASHsubsampled) remains at the discretion of the researcher.
 
+#### The `echo` entity 
+
+If the value of `EchoTime` metadata field varies at least once across a collection 
+of anatomical images having a common `grouping suffix`, the use of `echo-<index>`
+key/value pair is REQUIRED. Note that only integers (from 1 to N) are allowed as
+values to this entity for N different `EchoTime` parameter values. The actual 
+`EchoTime` parameter values MUST NOT be explicitly declared by the entity. Instead, 
+the parameter values are stored in sidecar json files and indexed by the `echo` entity
+in ascending order. For example: 
+
+```
+sub-01_echo-1_MEGRE.nii.gz
+sub-01_echo-1_MEGRE.json   (`EchoTime` = 0.0005)
+sub-01_echo-2_MEGRE.nii.gz 
+sub-01_echo-2_MEGRE.json   (`EchoTime` = 0.0015)
+sub-01_echo-3_MEGRE.nii.gz
+sub-01_echo-3_MEGRE.json   (`EchoTime` = 0.0025)
+```
+
+#### The `fa` entity 
+
+If the value of `FlipAngle` metadata field varies at least once across a collection 
+of anatomical images having a common `grouping suffix`, the use of `fa-<index>`
+key/value pair is REQUIRED. Note that only integers from 1 to N are allowed as
+values to this entity for N different `FlipAngle` parameter values. The actual 
+`FlipAngle` parameter values MUST NOT be explicitly declared by the entity. Instead,
+the parameter values are stored in sidecar json files and indexed by the `fa` entity
+in ascending order. For example:
+
+```
+sub-01_fa-1_VFA.nii.gz 
+sub-01_fa-1_VFA.json   (`FlipAngle` = 5)
+sub-01_fa-2_VFA.nii.gz 
+sub-01_fa-2_VFA.json   (`FlipAngle` = 25)
+```
+
+#### The `inv` entity 
+
+If the value of `InversionTime` metadata field varies at least once across a 
+collection of anatomical images having a common `grouping suffix`, the use of 
+`inv-<index>` key/value pair is REQUIRED. Note that only integers from 1 to N 
+are allowed as values to this entity for N different `InversionTime` parameter 
+values. The actual `InversionTime` parameter values MUST NOT be explicitly declared 
+by the entity. Instead, the parameter values are stored in sidecar json files and 
+indexed by the `inv` entity in ascending order. For example: 
+
+```
+sub-01_inv-1_IRT1.nii.gz
+sub-01_inv-1_IRT1.json     (`InversionTime` = 0.0050)
+sub-01_inv-2_IRT1.nii.gz
+sub-01_inv-2_IRT1.json     (`InversionTime` = 0.0100)
+sub-01_inv-3_IRT1.nii.gz
+sub-01_inv-4_IRT1.json     (`InversionTime` = 0.0150)
+```
+
+#### The `mt` entity 
+
+If a collection of anatomical images having a common `grouping suffix` includes
+at least one scan in which a magnetization transfer pulse is applied, the 
+`mt-<on/off>` key/value pair MUST BE used. The value of this entity can be either 
+`on` or `off` (in lowercase), as determined by the `MTState` metadata. For example: 
+
+```
+sub-01_mt-on_MTR.nii.gz
+sub-01_mt-on_MTR.json      (`MTState` = On)
+sub-01_mt-off_MTR.nii.gz
+sub-01_mt-off_MTR.json     (`MTState` = Off)
+```
+
 #### The `ce` entity
 
 Similarly the OPTIONAL `ce-<label>` key/value can be used to distinguish
@@ -188,6 +492,24 @@ fields specific to anatomical scans:
 | Field name              | Definition                                                                                                                                         |
 | -----------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------- |
 | ContrastBolusIngredient | OPTIONAL. Active ingredient of agent. Values MUST be one of: IODINE, GADOLINIUM, CARBON DIOXIDE, BARIUM, XENON Corresponds to DICOM Tag 0018,1048. |
+| RepetitionTimeExcitation | OPTIONAL. The time in seconds between successive excitation pulses that excite the same tissue. The DICOM tag that best refers to this parameter is [(0018, 0080)](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)). This field may be superseded by `RepetitionTimePreparation` for certain use cases, such as [MP2RAGE](https://infoscience.epfl.ch/record/172927/files/mp2rage.pdf). Use `RepetitionTimeExcitation` (in combination with `RepetitionTimePreparation` if needed) for anatomy imaging data rather than `RepetitionTime` as it is already defined as the amount of time that it takes to acquire a single volume in section 4.1.x. |
+| RepetitionTimePreparation | OPTIONAL. The period of time in seconds that it takes a preparation pulse block to re-appear at the beginning of the succeeding (essentially identical) pulse sequence. |
+
+##### Legacy suffixes (to be deprecated)
+
+Some suffixes that were available in versions of the specification prior to
+1.4.0. have been identified as legacy suffixes. The legacy suffixes generate
+inconsistencies and/or ambiguities with additional suffixes added in version
+1.4.0 and so are therefore not recommended for use in new datasets. They are,
+however, still valid suffixes, to maintain backwards compatibility.
+
+The following suffixes are valid, but SHOULD NOT be used for new BIDS compatible datasets (created after version 1.4.0.):
+
+| Name           | Suffix    | Description                                                    | Reason to deprecate                                                                                                                                                                                                                                                                                                                                                                                                |
+|----------------|-----------|----------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| T2\*           | T2star    | Not provided.                                                  | Ambiguous, may refer to a parametric image or to a conventional image. **Change:** Replaced by `T2starw` or `T2starmap`.                                                                                                                                                                                                                                                                                           |
+| FLASH          | FLASH     | Not provided.                                                  | FLASH (Fast-Low-Angle-Shot) is a vendor specific implementation for spoiled  gradient echo acquisition. It is commonly used for rapid anatomical imaging  and also for many different qMRI applications. Given the versatility and the popularity of the FLASH sequence, it can easily obfuscate purpose of a  `grouped scan collection` when used as a `grouping suffix`. **Change:** Removed from suffixes.     |
+| Proton Density | PD        | Not provided.                                                  | Ambiguous, may refer to a parametric image or to a conventional image. **Change:** Replaced by `PDw` or `PDmap`.                                                                                                                                                                                                                                                                                                   |
 
 ### Task (including resting state) imaging data
 
@@ -265,7 +587,8 @@ sub-01/
 
 Please note that the `<index>` denotes the number/index (in a form of an
 integer) of the echo not the echo time value which needs to be stored in the
-field EchoTime of the separate JSON file.
+field EchoTime of the separate JSON file (see also 
+[here](01-magnetic-resonance-imaging-data.md#the-echo-entity)).
 
 Some meta information about the acquisition MUST be provided in an additional
 JSON file.
@@ -273,8 +596,8 @@ JSON file.
 #### Required fields
 
 | Field name     | Definition                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
-|----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| RepetitionTime | REQUIRED. The time in seconds between the beginning of an acquisition of one volume and the beginning of acquisition of the volume following it (TR). Please note that this definition includes time between scans (when no data has been acquired) in case of sparse acquisition schemes. This value needs to be consistent with the `pixdim[4]` field (after accounting for units stored in `xyzt_units` field) in the NIfTI header. This field is mutually exclusive with `VolumeTiming` and is derived from DICOM Tag 0018, 0080 and converted to seconds. |
+|-----------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| RepetitionTime | REQUIRED. The time in seconds between the beginning of an acquisition of one volume and the beginning of acquisition of the volume following it (TR). When used in the context of functional acquisitions this parameter best corresponds to [DICOM Tag 0020,0110](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0020,0110)): the "time delta between images in a dynamic of functional set of images" but may also be found in [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)): "the period of time in msec between the beginning of a pulse sequence and the beginning of the succeeding (essentially identical) pulse sequence". This definition includes time between scans (when no data has been acquired) in case of sparse acquisition schemes. This value MUST be consistent with the '`pixdim[4]`' field (after accounting for units stored in '`xyzt_units`' field) in the NIfTI header. This field is mutually exclusive with `VolumeTiming`. |
 | VolumeTiming   | REQUIRED. The time at which each volume was acquired during the acquisition. It is described using a list of times (in JSON format) referring to the onset of each volume in the BOLD series. The list must have the same length as the BOLD series, and the values must be non-negative and monotonically increasing. This field is mutually exclusive with `RepetitionTime` and `DelayTime`. If defined, this requires acquisition time (TA) be defined via either `SliceTiming` or `AcquisitionDuration` be defined.                                        |
 | TaskName       | REQUIRED. Name of the task. No two tasks should have the same name. The task label included in the file name is derived from this TaskName field by removing all non-alphanumeric (`[a-zA-Z0-9]`) characters. For example TaskName `faces n-back` will correspond to task label `facesnback`. A RECOMMENDED convention is to name resting state task using labels beginning with `rest`.                                                                                                                                                                       |
 
@@ -432,6 +755,18 @@ JSON example:
 
 ### Fieldmap data
 
+All three of B0 (static magnetic field strength pattern), B1<sup>+</sup> (transmit field pattern), and
+B1<sup>-</sup> (receive field pattern) maps can be useful in post-processing raw functional and
+anatomical data.
+
+B0 maps are primarily used to correct for spatial distortions in functional data
+acquired with EPI sequences.
+
+B1<sup>+</sup> and B1<sup>-</sup>  maps are mostly used in anatomical imaging, especially
+in quantitative MRI applications. Further information about these radiofrequency (RF)
+field maps are available in the [qMRI appendix](../99-appendices/09-qmri.md).
+
+#### B0 fieldmaps
 Data acquired to correct for B0 inhomogeneities can come in different forms. The
 current version of this standard considers four different scenarios. Please note
 that in all cases fieldmap data can be linked to a specific scan(s) it was
@@ -462,7 +797,7 @@ Multiple fieldmaps can be stored. In such case the `_run-1`, `_run-2` should be
 used. The OPTIONAL `acq-<label>` key/value pair corresponds to a custom label
 the user may use to distinguish different set of parameters.
 
-#### Case 1: Phase difference image and at least one magnitude image
+##### Case 1: Phase difference image and at least one magnitude image
 
 Template:
 
@@ -497,7 +832,7 @@ the shorter echo time and `EchoTime2` to the longer echo time. Similarly
 }
 ```
 
-#### Case 2: Two phase images and two magnitude images
+##### Case 2: Two phase images and two magnitude images
 
 Template:
 
@@ -523,7 +858,7 @@ corresponding `EchoTime` values. For example:
 }
 ```
 
-#### Case 3: A real fieldmap image
+##### Case 3: A real fieldmap image
 
 Template:
 
@@ -547,7 +882,7 @@ the fieldmap. The possible options are: `Hz`, `rad/s`, or `Tesla`. For example:
 }
 ```
 
-#### Case 4: Multiple phase encoded directions ("pepolar")
+##### Case 4: Multiple phase encoded directions ("pepolar")
 
 Template:
 
diff --git a/src/99-appendices/01-contributors.md b/src/99-appendices/01-contributors.md
index a5b76298dc..ad6eec4a22 100644
--- a/src/99-appendices/01-contributors.md
+++ b/src/99-appendices/01-contributors.md
@@ -41,8 +41,10 @@ your name is not listed, please add it.
 -   Eric Bridgeford 📖🔧
 -   Teon L. Brooks 📖💻⚠️💬👀🤔🔧🐛📢
 -   Suyash Bhogawar 📖💡⚠️🔧💬
+-   Mathieu Boudreau 📖
 -   Vince D. Calhoun 📖
 -   Alexander L. Cohen 🐛💻📖💬
+-   Julien Cohen-Adad 📖
 -   R. Cameron Craddock 📖📢
 -   Sasha D'Ambrosio 📖
 -   Samir Das 📖
@@ -81,14 +83,17 @@ your name is not listed, please add it.
 -   Dora Hermes 📖💻✅🔍🤔
 -   Katja Heuer 🔧
 -   Chris Holdgraf 📖🤔
+-   Gilles de Hollander 📖🤔💡
 -   Christopher J. Honey 📖
 -   Jean-Christophe Houde 📖
 -   International Neuroinformatics Coordinating Facility 💵📋
 -   Andrew Janke 📖💻
 -   Mainak Jas 📖💻
 -   Alexander Jones 💻🐛
+-   Agâh Karakuzu 📖🤔💡
 -   David Keator 📖
 -   James Kent 💬💻
+-   Ali Khan 📖🤔
 -   Gregory Kiar 📖💻🎨🔧
 -   Robert Knight 📖
 -   Jean-Philippe Lachaux 📖
@@ -98,17 +103,21 @@ your name is not listed, please add it.
 -   Laura and John Arnold Foundation 💵
 -   Christopher Lee-Messer 📖
 -   Jon Haitz Legarreta 💻📖
+-   Ilana Leppert 📖
+-   Tobias Leutritz 📖
 -   Xiangrui Li 📖💻
 -   Vladimir Litvak 📖
 -   Brian N. Lundstrom 📖
 -   Dan Lurie 🤔📖🔧🔌💻💬
 -   Camille Maumet 📖
 -   Christopher J. Markiewicz 💬🐛💻📖🎨💡🤔🔌👀🔧📢
+-   José Marques 🤔
 -   Kai J. Miller 📖
 -   Jeremy Moreau 📖💡
 -   Zachary Michael 📖
 -   Ezequiel Mikulan 📖💻
 -   Michael P. Milham 💡🔍
+-   Martijn Mulder 📖🤔
 -   Henk Mutsaerts 📖
 -   National Institute of Mental Health 💵
 -   Mikael Naveau 🐛
@@ -143,8 +152,10 @@ your name is not listed, please add it.
 -   Matt Sanderson 📖💻
 -   Gunnar Schaefer 📖
 -   Jan-Mathijs Schoffelen 📖
+-   Julien Sein 📖
 -   Robert E. Smith 💻📖
 -   Vanessa Sochat 📖
+-   Isla Staden 📖
 -   Arjen Stolk 📖
 -   Nicole C. Swann 📖
 -   François Tadel 📖🔌💡
@@ -157,6 +168,8 @@ your name is not listed, please add it.
 -   Joseph Wexler 📖💡
 -   Kirstie Whitaker 📖💡🔍🤔📢💬
 -   Jonathan Winawer 📖
+-   Tobias Wood 📖
 -   Gaël Varoquaux 📖
 -   Tal Yarkoni 💻📖🤔🔍🔌👀📢🐛🎨
 -   Lyuba Zehl 📖
+-   Wietske van der Zwaag 📖🤔💡
diff --git a/src/99-appendices/04-entity-table.md b/src/99-appendices/04-entity-table.md
index ade3287c11..5bb604100e 100644
--- a/src/99-appendices/04-entity-table.md
+++ b/src/99-appendices/04-entity-table.md
@@ -13,8 +13,6 @@ A general introduction to entities is given in the section on
 | Entity                                                                                         | Subject       | Session       | Task           | Acquisition   | Contrast Enhancing Agent | Reconstruction | Phase-Encoding Direction | Run           | Corresponding modality | Echo           | Recording           | Processed (on device) | Space           | Split           |
 | :--------------------------------------------------------------------------------------------- | :------------ | :------------ | :------------- | :------------ | :----------------------- | :------------- | :----------------------- | :------------ | :--------------------- | :------------- | :------------------ | :-------------------- | :---------------| :-------------- |
 | Format                                                                                         | `sub-<label>` | `ses-<label>` | `task-<label>` | `acq-<label>` | `ce-<label>`             | `rec-<label>`  | `dir-<label>`            | `run-<index>` | `mod-<label>`          | `echo-<index>` | `recording-<label>` | `proc-<label>`        | `space-<label>` | `split-<index>` |
-| anat<br>(T1w T2w T1rho T1map T2map T2star FLAIR FLASH PD PDmap PDT2 inplaneT1 inplaneT2 angio) | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          |               |                        |                |                     |                       |                 |                 |
-| anat<br>(defacemask)                                                                           | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          |               | OPTIONAL               |                |                     |                       |                 |                 |
 | func<br>(bold cbv phase sbref events)                                                          | REQUIRED      | OPTIONAL      | REQUIRED       | OPTIONAL      | OPTIONAL                 | OPTIONAL       | OPTIONAL                 | OPTIONAL      |                        | OPTIONAL       |                     |                       |                 |                 |
 | func<br>(physio stim)                                                                          | REQUIRED      | OPTIONAL      | REQUIRED       | OPTIONAL      |                          | OPTIONAL       |                          | OPTIONAL      |                        |                | OPTIONAL            | OPTIONAL              |                 |                 |
 | dwi<br>(dwi bvec bval)                                                                         | REQUIRED      | OPTIONAL      |                | OPTIONAL      |                          |                | OPTIONAL                 | OPTIONAL      |                        |                |                     |                       |                 |                 |
@@ -30,3 +28,18 @@ A general introduction to entities is given in the section on
 | photo<br>(meg/eeg/ieeg)                                                                        | REQUIRED      | OPTIONAL      |                | OPTIONAL      |                          |                |                          |               |                        |                |                     |                       |                 |                 |        
 | electrodes<br>(eeg/ieeg)                                                                       | REQUIRED      | OPTIONAL      |                | OPTIONAL      |                          |                |                          |               |                        |                |                     |                       | OPTIONAL        |                 |
 | events<br>(meg/eeg/ieeg)                                                                       | REQUIRED      | OPTIONAL      | REQUIRED       |               |                          |                |                          | OPTIONAL      |                        |                |                     |                       |                 |                 |        
+
+## Entity table for anatomy imaging data
+
+| Entity                                                                                                     | Subject       | Session       | Task           | Acquisition   | Contrast Enhancing Agent | Reconstruction | Phase-Encoding Direction | Run           | Corresponding Modality | Echo           | Flip Angle   | Inversion Time | Magnetization Transfer | Part               | Recording           | Processed      | Space           |
+|------------------------------------------------------------------------------------------------------------|---------------|---------------|----------------|---------------|--------------------------|----------------|--------------------------|---------------|------------------------|----------------|--------------|----------------|------------------------|--------------------|---------------------|----------------|-----------------|
+| Format                                                                                                     | `sub-<label>` | `ses-<label>` | `task-<label>` | `acq-<label>` | `ce-<label>`             | `rec-<label>`  | `dir-<label>`            | `run-<index>` | `mod-<suffix>`         | `echo-<index>` | `fa-<index>` | `inv-<index>`  | `mt-<on/off>`          | `part-<label>` | `recording-<label>` | `proc-<label>` | `space-<label>` |
+| anat (T1w T2w  PDw T2starw  FLASH inplaneT1  inplaneT2)                                                    | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        |                |              |                |                        | OPTIONAL           |                     |                |                 |
+| anat (defacemask)                                                                                          | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      | OPTIONAL               |                |              |                |                        |                    |                     |                |                 |
+| anat (T1map T2map T2starmap R1map R2map R2starmap PDmap MTRmap MTsat UNIT1 T1rho MWFmap PDT2map B1plusmap) | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        |                |              |                |                        |                    |                     |                |                 |
+| anat (MESE MGRE)                                                                                           | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        | REQUIRED       |              |                |                        | OPTIONAL           |                     |                |                 |
+| anat (VFA)                                                                                           | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        |                | REQUIRED     |                |                        | OPTIONAL           |                     |                |                 |
+| anat (MP2RAGE)                                                                                             | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        | OPTIONAL       | REQUIRED     | REQUIRED       |                        | OPTIONAL           |                     |                |                 |
+| anat (MPM MTS)                                                                                             | REQURED       | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        | OPTIONAL       | REQUIRED     |                | REQUIRED               | OPTIONAL           |                     |                |                 |
+| anat (MTR)                                                                                                 | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        |                |              |                | REQUIRED               | OPTIONAL           |                     |                |                 |
+| anat (IRT1)                                                                                                | REQUIRED      | OPTIONAL      |                | OPTIONAL      | OPTIONAL                 | OPTIONAL       |                          | OPTIONAL      |                        |                |              | REQUIRED       |                        | OPTIONAL           |                     |                |                 |
\ No newline at end of file
diff --git a/src/99-appendices/09-qmri.md b/src/99-appendices/09-qmri.md
new file mode 100644
index 0000000000..6880805e67
--- /dev/null
+++ b/src/99-appendices/09-qmri.md
@@ -0,0 +1,477 @@
+This appendix contains detailed information on how to organize quantitative MRI
+data in the BIDS format.
+
+# Method-specific priority levels for grouping suffix
+
+Some of the metadata entries are REQUIRED for specific qMRI methods.
+These metadata are laid-out in the table below.
+
+<a name="prioritylevels">Table of method-specific priority levels for qMRI metadata</a>
+
+| Grouping suffix | REQUIRED metadata                                                                                    | OPTIONAL metadata          |
+|-----------------|------------------------------------------------------------------------------------------------------|----------------------------|
+| VFA             | `FlipAngle`, `PulseSequenceType`, `RepetitionTimeExcitation`                                         | `SpoilingRFPhaseIncrement` |
+| IRT1            | `InversionTime`                                                                                      |                           |
+| MP2RAGE         | `FlipAngle`, `InversionTime`, `RepetitionTimeExcitation`, `RepetitionTimePreperation`, `NumberShots` | `EchoTime`                 |
+| MESE            | `EchoTime`                                                                                           |                           |
+| MEGRE           | `EchoTime`                                                                                           |                           |
+| MTR             | `MTState`                                                                                            |                           |
+| MTS             | `FlipAngle`, `MTState`, `RepetitionTimeExcitation`                                                   |                           |
+| MPM             | `FlipAngle`, `MTState`, `RepetitionTimeExcitation`                                                   | `EchoTime`                 |
+| B1DAM           | `FlipAngle`                                                                                          |                          |
+
+Explanation of the table:
+
+* The metadata fields listed in the REQUIRED column are needed to perform a
+minimum viable qMRI application for the corresponding `grouping suffix`.
+* Note that some of the metadata fields may be unaltered across different members
+of a given `grouped scan collection`, yet still needed as an input to a qMRI
+model for parameter fitting (e.g. `RepetitionTimeExcitation` of `VFA`) and therefore
+should be included in all json-sidecars. 
+* The metadata fields listed in the OPTIONAL column can be used to derive
+various qMRI applications from an existing `grouping suffix`. 
+
+The following section expands on the set of rules to derive novel qMRI applications
+from an existing `grouping suffix`.
+
+# How to derive the intended qMRI application from an ambiguous `grouping suffix`
+
+Certain grouping suffixes may refer to a generic data collection regime such as
+variable flip angle (VFA), rather than a more specific acquisition, e.g.,
+magnetization prepared two gradient echoes (MP2RAGE). Such generic acquisitions
+can serve as a basis to derive various qMRI applications by changes to
+the acquisition sequence (e.g. readout) type or varying additional scan parameters.
+
+If such an inheritance relationship is applicable between an already existing
+`grouping suffix` and a new qMRI application to be included in the specification,
+the inheritor qMRI method MUST be listed in the table below instead of
+introducing a new `grouping suffix`. This approach:
+
+* prevents the list of available suffixes from over-proliferation
+* provides qMRI-focused BIDS applications with a set of meta-data driven rules
+to infer possible fitting options
+* keep an inheritance track of the qMRI methods described within the
+specification.
+
+<a name="varianttable">Table of qMRI applications that can be derived from an existing grouping suffix</a>
+
+| Grouping suffix | If REQUIRED metadata == Value | OPTIONAL metadata [`var`/`fix`]<sup>[*](#footnotederive)</sup>      | Derived application |
+|-----------------|-------------------------------|----------------------------------|---------------------|
+| VFA             | `PulseSequenceType` == `SPGR` |                                  | DESPOT1             |
+| VFA             | `PulseSequenceType` == `SSFP` | `SpoilingRFPhaseIncrement` [`fix`] | DESPOT2             |
+| VFA             | `PulseSequenceType` == `SSFP` | `SpoilingRFPhaseIncrement` [`var`] | DESPOT2-FM          |
+| MP2RAGE         |                               | `EchoTime` [`var`]                 | MP2RAGE-ME          |
+| MPM             |                               | `EchoTime` [`var`]                 | MPM-ME              |
+
+<a name="footnotederive">*</a> `var` denotes that the listed OPTIONAL metadata value changes across
+ constituent images of the respective `grouping suffix`, fixed otherwise (`fix`). 
+ If the OPTIONAL metadata type is `var`, respective naming entities can be found in the 
+ OPTIONAL entities column of [`grouping suffix` table](#grouping-suffix). 
+
+* * *
+
+A derived qMRI application becomes avaiable if all the OPTIONAL metadata fields
+listed for a `grouping suffix` is provided for the data. In addition, conditional
+rules based on the value of a given REQUIRED metada field can be set
+for the description of a derived qMRI application. Note that the value of this
+REQUIRED metadata is fixed across constituent images of a `grouping suffix`. 
+
+For example, if the REQUIRED metadata field of `PulseSequenceType` is SPGR
+for a collection of anatomical images listed by the `VFA` suffix, the data
+qualifies for `DESPOT1` T1 fitting. For the same suffix, if the `PulseSequenceType`
+metadata field has the value of `SSFP`, and the `SpoilingRFPhaseIncrement` is 
+provided as a metadata field, then the dataset becomes eligible for `DESPOT2`
+T2 fitting application. Finally, if the `DESPOT2` data has more than one
+`SpoilingRFPhaseIncrement` field as a metadata field, then the dataset is valid
+for `DESPOT2-FM`. In this case, `rfphase` entity can be used to distinguish inputs. 
+
+Please note that OPTIONAL metadata fields listed in the 
+qMRI applications that can be derived from an existing suffix table](#varianttable) MUST
+also be included in the
+[method sprecific priority levels for qMRI metadata table](#prioritylevels) for the sake of completeness.
+
+Please also note that the rules concerning the presence/value of certain metadata
+fields within the context of `grouping suffix` is not a part of the BIDS
+validation process. Such rules rather constitute a centralized guideline for
+creating interoperable qMRI datasets.
+
+For a dataset with a `grouping suffix`, the BIDS validation is successful if:
+
+* provided NIfTI and JSON file names respect the anatomy imaging dataset template
+* provided suffixes are present in the list of available suffixes
+* sidecar JSON files follow the hierarchy defined for `grouping suffix`.
+
+# Introducing a new qMRI grouping suffix
+
+In the future, novel qMRI applications will be introduced that are not yet
+described by the BIDS. If such applications can not be interpreted as a 
+subset of a pre-existing `grouping suffix`,
+a new grouping suffix can be introduced, but should adhere to the following
+principles:
+
+* All grouping suffixes MUST be capitalized.
+* Grouping suffixes MUST attain a clear description of the qMRI application
+that they relate to. Hyperlinks to example applications and/or more detailed
+descriptions are encouraged whenever possible.
+* Unless the pulse sequence is exclusively associated with a specific qMRI
+application (e.g. `MP2RAGE`), sequence names are NOT used as grouping suffixes.
+* If it is possible to derive a qMRI application from an already existing
+grouping suffix by defining a set of logical conditions over the metadata
+fields, the [table of method-specific priority levels](#prioritylevels) and the
+[table of qMRI applications that can be derived from an existing grouping suffix](#varianttable)
+MUST be expanded instead of introducing a new grouping suffix.
+Please visit the [JSON content for grouping suffixes](#whichmetadata) 
+for further details.
+* Please note that if a structural data has the type of grouped scan collection,
+the use of `_suffix` alone cannot distinguish its members from each other,
+failing to identify their roles as inputs to the calculation of qMRI maps.
+Although such images are REQUIRED to be grouped by a proper grouping suffix,
+they are also RECOMMENDED to include at least one of the `acq`, `part`, `echo`,
+`met`, `inv`-key/value-pairs  to indicate which scanning parameters are 
+systematically altered.
+
+
+# Management of the qMRI maps
+
+All qMRI maps are generated following a set of calculations. Unlike conventional 
+MR images, they are not products of an MRI image reconstruction (from k-space data 
+to structural images). There are two possible options in the way a qMRI map is obtained: 
+
+1. Pre-generated qMRI maps: The qMRI maps are generated immediately after the 
+reconstruction of the multi-contrast input images and made available to the user
+at the scanner console. The acquisition scenarios may include (a) vendor pipelines 
+or (b) open-source pipelines deployed at the scanner site.
+2. Post-generated qMRI maps: The qMRI maps are generated from the multi-contrast
+input images after they are exported outside of the scanner site.
+
+## Where to place qMRI maps? 
+
+**If the provenance record of the qMRI map generation is NOT accessible:**
+
+Although qMRI maps are derivatives by definition, we cannot relate them to their 
+multi-contrast input images in this case. Therefore, qMRI maps lacking provenance
+are directly placed at the `/sub-#/anat` directory.
+
+**If the provenance record of the qMRI map generation is available:**
+
+In this case, qMRI maps SHOULD be stored in the `derivatives` folder, but MAY
+be symbolic linked to the corresponding raw data directory to facilitate the
+easy use of these images as inputs to the processing workflows implemented as
+BIDS-apps. For example:
+
+```diff
+ ds-example/
+ ├── derivatives/
+ |   └── qMRI-software/
+ |       └── sub-01/
+ |           └── anat/
+ |               ├── sub-01_T1map.nii.gz ─────────┐ S
+ |               ├── sub-01_T1map.json   ───────┐ | Y
+ |               ├── sub-01_MTsat.nii.gz ─────┐ | | M
+ |               └── sub-01_MTsat.json   ───┐ | | | L 
+ └── sub-01/                                | | | | I
+     └── anat/                              | | | | N
+         ├── sub-01_T1w.nii.gz              | | | | K
+         ├── sub-01_T1w.json                | | | | 
+         ├── sub-01_fa-1_mt-on_MTS.nii.gz   | | | | T
+         ├── sub-01_fa-1_mt-on_MTS.json     | | | | O 
+         ├── sub-01_fa-1_mt-off_MTS.nii.gz  | | | | 
+         ├── sub-01_fa-1_mt-off_MTS.json    | | | | A
+         ├── sub-01_fa-2_mt-off_MTS.nii.gz  | | | | N
+         ├── sub-01_fa-2_mt-off_MTS.json    | | | | A
+         ├── sub-01_T1map.nii.gz ◀──────────├─├─├─┘ T
+         ├── sub-01_T1map.json   ◀──────────├─├─┘   
+         ├── sub-01_MTsat.nii.gz ◀──────────├─┘
+         └── sub-01_MTsat.json   ◀──────────┘ 
+```
+
+In the example above, outputs of the `MTS` that are placed under the `derivatives`
+folder are symbolic linked to the respective `anat` folder. This way, an
+application can easily pick up a qMRI map along with other anatomical images.
+
+## <a name="whichmetadata">Which metadata fields should a qMRI map contain?</a>
+
+**If the provenance record of the qMRI map generation is NOT accessible:**
+
+JSON content is confined to the metadata made available for the pre-generated
+qMRI map.
+
+**If the provenance record of the qMRI map generation is available:**
+
+JSON file of the qMRI map MUST inherit metadata from its parent images (typically a grouped scan 
+collection) by adhering to the following rules:
+* All the acquisition parameters that are unchanged across constituents of
+a `grouped scan collection` are added to the JSON file of the resultant
+qMRI map.
+* Relevant acquisition parameters that vary across constituents of a
+`grouped scan collection` are added to the JSON file of the resultant
+qMRI map **`in array form`**. 
+ > To find out which varying scan parameters are
+ relevant to a given `grouped scan collection`, please see the
+[method-specific priority levels for qMRI metadata](#prioritylevels) above.
+* The JSON file accompanying a qMRI map which is obtained by
+using open-source software MUST include all the metadata fields listed
+in the following table for the sake of provenance.
+
+| Field name                  | Definition                                                     |
+| :-------------------------- | :------------------------------------------------------------- |
+| BasedOn | List of files grouped by an `grouping suffix` to generate the map. Fieldmaps are also listed, if involved in the processing. |
+| EstimationReference | Reference to the study/studies on which the implementation is based.|
+| EstimationAlgorithm | Type of algoritm used to perform fitting (e.g. linear, non-linear, LM etc.)|
+| EstimationSoftwareName | The name of the open-source tool used for fitting (e.g. [qMRLab](https://qmrlab.org), [QUIT](https://github.com/spinicist/QUIT), [hMRI-Toolbox](https://hmri-group.github.io/hMRI-toolbox/) etc.)|
+| EstimationSoftwareVer | Version of the open-source tool used for fitting (e.g. v2.3.0 etc.)|
+| EstimationSoftwareLang | Language in which the software is natively developed (e.g. MATLAB R2018b, C++17, Python 3.6 etc.)|
+| EstimationSoftwareEnv | Operation system on which the application was run (e.g. OSX 10.14.3, Ubuntu 18.04, Win10 etc.)|
+
+Example:
+
+```Text
+sub-01_T1map.nii.gz
+sub-01_T1map.json
+```
+
+```
+sub-01_T1map.json
+{
+
+<<Parameter injected by the software for provenance recording>>
+
+"BasedOn":["anat/sub-01_fa-1_VFA.nii.gz",
+           "anat/sub-01_fa-2_VFA.nii.gz",
+           "anat/sub-01_fa-3_VFA.nii.gz",
+           "anat/sub-01_fa-4_VFA.nii.gz",
+           "fmap/sub-01_TB1map.nii.gz"],
+
+<<Parameters that are constant across members of VFA grouping suffix>>
+
+“MagneticFieldStrength”: “3”,
+“Manufacturer”: “Siemens”,
+“ManufacturerModelName”: “TrioTim”,
+“InstitutionName”: “xxx”,
+“PulseSequenceType”: “SPGR”,
+“PulseSequenceDetails”: “Information beyond the sequence type that identifies
+ specific pulse sequence used (VB version, if not standard, Siemens WIP XXX
+ ersion ### sequence written by xx using a version compiled on mm/dd/yyyy/)”,
+"RepetitionTimeExcitation": "35",
+"EchoTime": "2.86",
+"SliceThickness": "5",
+
+<<Relevant parameters that vary across members of VFA grouping suffix>>
+
+"FlipAngle": ["5","10","15","20"],
+
+<<Additional parameters injected by the software for provenance recording>>
+
+"EstimationPaper":"Deoni et. al.MRM, 2015",
+"EstimationAlgorithm":"Linear",
+“EstimationSoftwareName”: “qMRLab”,
+“EstimationSoftwareLanguage”: “Octave”,
+“EstimationSoftwareVersion”: “2.3.0”,
+“EstimationSoftwareEnv”: “Ubuntu 16.04”
+}
+```
+
+# Radiofrequency (RF) field mapping 
+
+Most qMRI methods are susceptible to nonuniformities in the transmit (B1<sup>+</sup>)
+and/or receive (B1<sup>-</sup>) radiofrequency (RF) fields. Various (acquisition based)
+methods are available to derive maps of spatial variations in the B1<sup>+</sup>
+and B1<sup>-</sup> fields. These maps are commonly used for the correction of qMRI
+estimation errors arising from the imperfections in the respective RF field.
+
+An approach similar to that used in anatomical MR images to group a set of input images
+intended for qMRI application (`grouping suffix`) is applied for the inputs of
+B1<sup>+</sup> and B1<sup>-</sup> RF field mapping. Note that these images do not
+convey substantial structural information by design. Therefore, both inputs and
+outputs of RF field maps are stored in the `fmap` folder.
+
+## Grouping suffixes for RF field mapping 
+
+| Name                                       | Suffix  | Type     | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|--------------------------------------------|---------|----------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Double-angle B1<sup>+</sup> mapping                    | TB1DAM   | RF Grouping | Groups images for B1<sup>+</sup> field mapping ([Insko and Bolinger 1993](https://www.sciencedirect.com/science/article/abs/pii/S1064185883711332)). Double angle method is based on the calculation of the actual angles from signal ratios, collected by two acquisitions at different nominal excitation flip angles. Common sequence types for this application include spin echo and echo planar imaging. _Associated output suffixes_: `TB1map`                                                                                                                                                      |
+| B1<sup>+</sup> mapping with 3D EPI            | TB1EPI   | RF Grouping | Groups images for B1<sup>+</sup> field mapping ([Jiru and Klose 2006](https://dx.doi.org/10.1002/mrm.21083)). This method is based on two EPI readouts to acquire spin echo (SE) and stimulated echo (STE) images at multiple flip angles in one sequence, used in the calculation of deviations from the nominal flip angle. _Associated output suffixes_: `TB1map`                                                                                                                                                      |
+| Actual Flip Ange Imaging (AFI)             | TB1AFI   | RF Grouping | Groups images for B1<sup>+</sup> field mapping ([Yarnykh 2007](https://dx.doi.org/10.1002/mrm.21120)). This method calculates a B1<sup>+</sup> map from two images acquired at interleaved (two) TRs with identical RF pulses using a steady-state sequence. _Associated output suffixes_: `TB1map`                                                                                                                                                      |
+| Siemens `tfl_b1_map`             | TB1TFL   | RF Grouping | Groups images acquired using `tfl_b1_map` product sequence by Siemens based on the method by [Chung et al. (2010)](https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.22423). The sequence generates one ~anatomical image and one scaled flip angle map._Associated output suffixes_: `TB1map`                                                                                                                                                      |
+| Siemens `rf_map`             | TB1RFM   | RF Grouping | Groups images acquired using `rf_map` product sequence by Siemens, using a method combining SE and STE images with EPI readout similar to that by ([Jiru and Klose 2006](https://dx.doi.org/10.1002/mrm.21083)). The sequence generates one ~anatomical image and one scaled flip angle map. _Associated output suffixes_: `TB1map`                                                                                                                                                      |
+|Saturation‐prepared with 2 rapid Gradient Echoes (SA2RAGE) B1<sup>+</sup> mapping | TB1SRGE | RF Grouping |Groups images for  B1+ field mapping ([Eggenschwiler et al. 2011](https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.23145)). SA2RAGE uses a ratio of two saturation recovery images with different time delays, and a simulated look-up table to estimate B1+. This sequence can also be used in conjunction with MP2RAGE T1 mapping to iteratively improve B1+ and T1 map estimation ([Marques & Gruetter 2013](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0069294)). Associated output suffixes: TB1map                                                                                                                                                     |
+| B1<sup>-</sup> field correction          | RB1COR   | RF Grouping | Groups low resolution images acquired by the body coil (in the gantry of the scanner) and the head coil using identical acquisition parameters to generate a combined sensitivity map as described in [Papp et al. (2016)](https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.26058). _Associated output suffixes_: `RB1map`                                                                                                                                                      |
+
+
+## Entity specifications for RF field mapping grouping suffixes
+
+### `TB1DAM` 
+
+The `fa` entity MUST be used to distinguish images with this suffix: 
+
+```
+└── sub-01/
+     └── fmap/
+         ├── sub-01_fa-1_TB1DAM.nii.gz
+         ├── sub-01_fa-1_TB1DAM.json
+         ├── sub-01_fa-2_TB1DAM.nii.gz
+         └── sub-01_fa-2_TB1DAM.json
+```
+
+### `TB1EPI`
+
+The `fa` and `echo` entities MUST be used to distinguish images with this suffix.
+The use of `fa` follows the default convention. However, this suffix defines a
+specific use case for the `echo` entity:
+
+|`echo-1`|`echo-2`|
+|:--|:----|
+|Lower `EchoTime` | Higher `EchoTime`                  |
+|Spin Echo (SE) image|Stimulated Echo (STE) image|
+
+At each `FlipAngle`, the `TB1EPI` suffix lists two images acquired at two echo times.
+The first echo is a spin echo (SE) formed by the pulses alpha-2alpha. However, the 
+second echo in this method is generated in a different fashion compared to a typical
+MESE acquisition. The second echo is a stimulated echo (STE) that is formed by an 
+additional alpha pulse (i.e., alpha-2alpha-alpha).
+
+The `FlipAngle` value corresponds to the nominal flip angle value of the STE pulse. 
+The nominal FA value of the SE pulse is twice this value.
+
+Note that the following metadata fields MUST be defined in the accompanying JSON 
+files:
+
+| Field name         | Definition |
+| :----------------- | :--------- |
+| `TotalReadoutTime` |   The effective readout length defined as `EffectiveEchoSpacing * PEReconMatrix`, with `EffectiveEchoSpacing = TrueEchoSpacing / PEacceleration`         |
+| `MixingTime`       |  Time interval between the SE and STE pulses          |
+
+To properly identify constituents of this particular method, values of the `echo`
+entity MUST index the images as follows:  
+
+```
+└── sub-01/
+     └── fmap/
+         ├── sub-01_fa-1_echo-1_TB1EPI.nii.gz (SE)
+         ├── sub-01_fa-1_echo-1_TB1EPI.json
+         ├── sub-01_fa-1_echo-2_TB1EPI.nii.gz (STE)
+         ├── sub-01_fa-1_echo-2_TB1EPI.json
+         ├── sub-01_fa-2_echo-1_TB1EPI.nii.gz (SE)
+         ├── sub-01_fa-2_echo-1_TB1EPI.json
+         ├── sub-01_fa-2_echo-2_TB1EPI.nii.gz (STE)
+         └── sub-01_fa-2_echo-2_TB1EPI.json
+```
+
+### `TB1AFI`
+
+This method calculates a B1<sup>+</sup> map from two images acquired at two
+interleaved excitation repetition times (TR). Note that there is not an entity 
+for the TR and its definition depends on the modality (`functional` or `anatomical`)
+in the specification. 
+
+Therefore, to properly identify constituents of this particular method, values of 
+the `acq` entity SHOULD begin with either `tr1` (lower TR) or `tr2` (higher TR) 
+and MAY be followed by freeform entries:  
+
+|First `TR`|Second `TR`|Use case|
+|:--|:----| :----| 
+|`_acq-tr1`|`_acq-tr2`|Single acquisition|
+|`_acq-tr1Test`|`_acq-tr2Test`|Acquisition `Test`|
+|`_acq-tr1Retest`|`_acq-tr2Retest`|Acquisition `Retest`|
+
+```
+└── sub-01/
+     └── fmap/
+         ├── sub-01_acq-tr1_TB1AFI.nii.gz
+         ├── sub-01_acq-tr1_TB1AFI.json
+         ├── sub-01_acq-tr2_TB1AFI.nii.gz
+         └── sub-01_acq-tr2_TB1AFI.json
+```
+
+### `TB1TFL` and `TB1RMF`
+
+These suffixes describe two outputs generated by Siemens `tfl_b1_map` and `rf_map`
+product sequences, respectively. Both sequences output two images. The first image
+appears like an anatomical images and the second output is a scaled flip angle map.
+
+To properly identify constituents of this particular method, values of 
+the `acq` entity SHOULD begin with either `anat` or `famp` and MAY be followed 
+by freeform entries:
+
+|Anatomical (like) image|Scaled FA map|Use case|
+|:--|:----| :----| 
+|`_acq-anat`|`_acq-famp`|Single acquisition|
+|`_acq-anatTest`|`_acq-fampTest`|Acquisition `Test`|
+|`_acq-anatRetest`|`_acq-fampRetest`|Acquisition `Retest`|
+
+```
+└── sub-01/
+     └── fmap/
+         ├── sub-01_acq-anat_TB1TFL.nii.gz 
+         ├── sub-01_acq-anat_TB1TFL.json
+         ├── sub-01_acq-famp_TB1TFL.nii.gz
+         └── sub-01_acq-famp_TB1TFL.json
+```
+
+The example above applies to the `TB1RFM` suffix as well. 
+
+### `RB1COR`
+
+This method generates a sensitivity map by combining two low resolution images
+collected by two transmit coils (the body and the head coil) upon subsequent scans
+with identical acquisition parameters.
+
+To properly identify constituents of this particular method, values of the `acq`
+entity SHOULD begin with either `body` or `head` and MAY be followed by freeform
+entries:  
+
+|Body coil|Head coil|Use case|
+|:--|:----| :----| 
+|`_acq-body`|`_acq-head`|Single acquisition|
+|`_acq-bodyMTw`|`_acq-headMTw`|`MTw` for `MPM`|
+|`_acq-bodyPDw`|`_acq-headPDw`|`PDw` for `MPM`|
+|`_acq-bodyT1w`|`_acq-headT1w`|`T1w` for `MPM`|
+
+```
+└── sub-01/
+     └── fmap/
+         ├── sub-01_acq-body_RB1COR.nii.gz (Body coil)
+         ├── sub-01_acq-body_RB1COR.json
+         ├── sub-01_acq-head_RB1COR.nii.gz (Head coil)
+         └── sub-01_acq-head_RB1COR.json
+```
+
+## Where to place RF field maps? 
+
+**If the provenance record of the RF field map generation is NOT accessible:**
+
+RF field maps lacking provenance are directly placed at the `/sub-#/fmap` directory.
+
+**If the provenance record of the RF rield map generation is available:**
+
+RF field maps SHOULD be stored in the `derivatives` folder, but MAY
+be symbolic linked to the corresponding raw data directory to facilitate the
+easy use of these images as input to processing workflows implemented as
+BIDS-apps. For example:
+
+```diff
+ ds-example/
+ ├── derivatives/
+ |   └── qMRI-software/
+ |       └── sub-01/
+ |           └── fmap/
+ |               ├── sub-01_acq-PDw_RB1map.nii.gz        ─────────┐ 
+ |               ├── sub-01_acq-PDw_RB1map.json          ───────┐ | 
+ |               ├── sub-01_TB1map.nii.gz                ─────┐ | | 
+ |               └── sub-01_TB1map.json                  ───┐ | | | 
+ └── sub-01/                                                | | | | S
+     └── fmap/                                              | | | | Y
+         ├── sub-01_acq-bodyPDw_RB1COR.nii.gz               | | | | M
+         ├── sub-01_acq-bodyPDw_RB1COR.json                 | | | | L
+         ├── sub-01_acq-headPDw_RB1COR.nii.gz               | | | | I
+         ├── sub-01_acq-headPDw_RB1COR.json                 | | | | N
+         ├── sub-01_fa-1_TB1DAM.nii.gz                      | | | | K
+         ├── sub-01_fa-1_TB1DAM.json                        | | | | 
+         ├── sub-01_fa-2_TB1DAM.nii.gz                      | | | | T
+         ├── sub-01_fa-2_TB1DAM.json                        | | | | O
+         ├── sub-01_acq-PDw_RB1map.nii.gz      ◀────────────├─├─├─┘
+         ├── sub-01_acq-PDw_RB1map.json        ◀────────────├─├─┘
+         ├── sub-01_TB1map.nii.gz              ◀────────────├─┘
+         └── sub-01_TB1map.json                ◀────────────┘
+
+```