Susceptibility distortion correction: None

Running pilots using fmriprep-docker. Preprocessed data shows no SDC:

Susceptibility distortion correction: None

Created BIDS folders w/ associated .nii/.json using dcm2bids version 2.1.6. When running BIDS validator, receiving no errors. For task pilot MID, the end of BIDS file includes the IntendedFor:

"IntendedFor": [
        "func/sub-01_ses-1_task-mid_run-01_bold.nii.gz",
        "func/sub-01_ses-1_task-mid_run-02_bold.nii.gz"
    ]
}

Complete .json for AP.json file is provided: sub-31_ses-1_dir-AP_epi-mid.txt (2.7 KB)

Below is the folder structure for a given subject (truncating excess tasks/ses). Unclear as to why the fieldmaps are not recognized/utilized.

Sub has two sessions; func has three tasks (mid [2] runs; faces [1] run; resting [1] run)

sub-01
├── ses-1
│   ├── anat
│   │   ├── sub-01_ses-1_T1w.json
│   │   ├── sub-01_ses-1_T1w.nii.gz
│   │   ├── sub-01_ses-1_inplaneT1.json
│   │   └── sub-01_ses-1_inplaneT1.nii.gz
│   ├── fmap
│   │   ├── sub-01_ses-1_dir-AP_epi-faces.json
│   │   ├── sub-01_ses-1_dir-AP_epi-faces.nii.gz
│   │   ├── sub-01_ses-1_dir-AP_epi-mid.json
│   │   ├── sub-01_ses-1_dir-AP_epi-mid.nii.gz
│   │   ├── sub-01_ses-1_dir-AP_epi-resting.json
│   │   ├── sub-01_ses-1_dir-AP_epi-resting.nii.gz
│   │   ├── .....
│   └── func
│       ├── sub-01_ses-1_task-mid_run-01_bold.json
│       ├── sub-01_ses-1_task-mid_run-01_bold.nii.gz
│       ├── sub-01_ses-1_task-mid_run-01_events.tsv
│       ├── sub-01_ses-1_task-mid_run-01_recording-cardiac_physio.json
│       ├── sub-01_ses-1_task-mid_run-01_recording-cardiac_physio.tsv.gz
│       ├── sub-01_ses-1_task-mid_run-01_recording-respiratory_physio.json
│       ├── sub-01_ses-1_task-mid_run-01_recording-respiratory_physio.tsv.gz
│       ├── sub-01_ses-1_task-mid_run-02_bold.json
│       ├── sub-01_ses-1_task-mid_run-02_bold.nii.gz
│       ├── sub-01_ses-1_task-mid_run-02_events.tsv
│       ├── sub-01_ses-1_task-mid_run-02_recording-cardiac_physio.json
│       ├── ...
└── ses-2
    ├── ....```

Hi,

Please refer to the bids specification for the files in fmap/ folder. The suffix should be epi in your case.

1 Like

I’m replying to this thread because the solution above hasn’t worked for me.

I’m running fMRIPrep v25.0.0 locally, which keeps returning output without distortion correction (Susceptibility distortion correction: None). The data set is BIDS-valid. Here is the folder structure for one subject:

sub-010001
|–– ses-02
|   |–– anat
|   |   |–– sub-010001_ses-02_acq-mp2rage_T1w.json
|   |   |__ sub-010001_ses-02_acq-mp2rage_T1w.nii.gz
|   |–– fmap
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-01_magnitude1.json
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-02_magnitude1.json
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-02_magnitude1.nii.gz
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-01_magnitude2.json
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-02_magnitude2.json
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-01_magnitude2.nii.gz
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-02_magnitude2.nii.gz
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-01_phasediff.json
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-02_phasediff.json
|   |   |–– sub-010001_ses-02_acq-GEfmap_run-01_phasediff.nii.gz
|   |   |__ sub-010001_ses-02_acq-GEfmap_run-02_phasediff.nii.gz
|   |–– func
|   |   |–– sub-010001_ses-02_task-rest_acq-AP_run-01_bold.json
|   |   |–– sub-010001_ses-02_task-rest_acq-PA_run-01_bold.json
|   |   |–– sub-010001_ses-02_task-rest_acq-AP_run-01_bold.nii.gz
|   |   |–– sub-010001_ses-02_task-rest_acq-PA_run-01_bold.nii.gz
|   |   |–– sub-010001_ses-02_task-rest_acq-AP_run-02_bold.json
|   |   |–– sub-010001_ses-02_task-rest_acq-PA_run-02_bold.json
|   |   |–– sub-010001_ses-02_task-rest_acq-AP_run-02_bold.nii.gz
|   |   |__ sub-010001_ses-02_task-rest_acq-PA_run-02_bold.nii.gz

As far as I can tell, the fmap json files have the correct fields (including “IntendedFor” fields pointing to the correct subject-relative path). Here is the json file for the phasediff run-01 file above:

{
    "RepetitionTime": 0.68,
    "EchoTime1": 0.00519,
    "EchoTime2": 0.00765,
    "MagneticFieldStrength": 3,
    "FlipAngle": 60,
    "PhaseEncodingDirection": "i-",
    "ManufacturersModelName": "Verio",
    "IntendedFor": [
        "ses-02/func/sub-010001_ses-02_task-rest_acq-AP_run-01_bold.nii.gz",
        "ses-02/func/sub-010001_ses-02_task-rest_acq-PA_run-01_bold.nii.gz"
    ],
    "ImageType": [
        "ORIGINAL",
        "PRIMARY",
        "P",
        "ND"
    ],
    "Manufacturer": "Siemens",
    "SkullStripped": false,
    "B0PhaseIdentifier": "phasediff_fmap0"
}

Here is the fmriprep command I’ve been running. Notably, I’m skipping skull-stripping because I’ve already skull-stripped the T1 anatomical volumes using SynthStrip.

fmriprep \
	${root_dir}/nordic \
	${root_dir}/fmriprep \
	participant \
	--participant_label ${subj} \
	--fs-no-reconall \
	--skull-strip-t1w skip \
	--output-spaces MNI152NLin2009cAsym \
	--clean-workdir \
	--work-dir ${root_dir}/fmriprep/work

Is there some minor formatting error that is preventing fMRIPrep from running distortion correction? Could it be a problem with using the pre-skull-stripped anatomical? Thanks in advance for the help getting distortion correction to run correctly.

Hi @Phil, and welcome to neurostars!

If not using a container, you should use a container.

It looks like you also tried to specify the B0FieldIdentifier/Source but included a typo (Phase instead of Field).

If you specify both the IntendedFor and B0Field* methods, fmriprep will ignore the IntendedFor. Perhaps first try making sure you correctly specify your B0FieldSource/B0FieldIdentifier pairs.

In your phasediff jsons, have "B0FieldIdentifier": "whatever_you_want_to_name_fmap"

In your BOLD jsons, include "B0FieldSource": "whatever_you_named_corresponding_fmap"

Also, it is recommended to not include --fs-no-reconall.

The BIDS validator output would also be useful in seeing if there are other errors.

Best,
Steven

Hi @Steven, thanks so much for the quick response. fMRIPrep is still not performing susceptibility distortion correction, even after I changed the B0FieldIdentifier and B0FieldSource fields as you recommended. Do I also need to add B0FieldIdentifier to the magnitude1 json file?

Here is my new json file for the phasediff run-01 file:

{
    "RepetitionTime": 0.68,
    "EchoTime1": 0.00519,
    "EchoTime2": 0.00765,
    "MagneticFieldStrength": 3,
    "FlipAngle": 60,
    "PhaseEncodingDirection": "i-",
    "ManufacturersModelName": "Verio",
    "IntendedFor": [
        "ses-02/func/sub-010001_ses-02_task-rest_acq-AP_run-01_bold.nii.gz",
        "ses-02/func/sub-010001_ses-02_task-rest_acq-PA_run-01_bold.nii.gz"
    ],
    "ImageType": [
        "ORIGINAL",
        "PRIMARY",
        "P",
        "ND"
    ],
    "Manufacturer": "Siemens",
    "SkullStripped": false,
    "B0FieldIdentifier": "phasediff_run-01"
}

And here is a corresponding BOLD json:

{
    "EchoTime": 0.0394,
    "RepetitionTime": 1.4,
    "PartialFourier": 0.75,
    "MagneticFieldStrength": 3,
    "FlipAngle": 69,
    "CogAtlasID": "http://www.cognitiveatlas.org/task/rest_eyes_open",
    "SliceTiming": [
        0,
        0.615,
        1.23,
        0.44,
        1.055,
        0.2625,
        0.8775,
        0.0875,
        0.7025,
        1.3175,
        0.5275,
        1.1425,
        0.3525,
        0.965,
        0.175,
        0.79,
        0,
        0.615,
        1.23,
        0.44,
        1.055,
        0.2625,
        0.8775,
        0.0875,
        0.7025,
        1.3175,
        0.5275,
        1.1425,
        0.3525,
        0.965,
        0.175,
        0.79,
        0,
        0.615,
        1.23,
        0.44,
        1.055,
        0.2625,
        0.8775,
        0.0875,
        0.7025,
        1.3175,
        0.5275,
        1.1425,
        0.3525,
        0.965,
        0.175,
        0.79,
        0,
        0.615,
        1.23,
        0.44,
        1.055,
        0.2625,
        0.8775,
        0.0875,
        0.7025,
        1.3175,
        0.5275,
        1.1425,
        0.3525,
        0.965,
        0.175,
        0.79
    ],
    "PulseSequenceType": "Multiband gradient echo EPI",
    "PhaseEncodingDirection": "j-",
    "MultibandAccelerationFactor": 4,
    "EffectiveEchoSpacing": 0.000669986,
    "ManufacturersModelName": "Verio",
    "ReceiveCoilName": "Siemens 32-channel phased-array",
    "TaskName": "Rest",
    "Instructions": "Eyes open",
    "ImageType": [
        "ORIGINAL",
        "PRIMARY",
        "M",
        "ND",
        "MOSAIC"
    ],
    "Manufacturer": "Siemens",
    "SkullStripped": false,
    "B0FieldSource": "phasediff_run-01"
}

Also, here is the BIDS validator output (broken up into two posts):

	[WARNING] SIDECAR_KEY_RECOMMENDED A data file's JSON sidecar is missing a key listed as recommended.
		Description
		/CHANGES - Field description: Free-form natural language description.

		/README - Field description: Free-form natural language description.


		3894 more files with the same issue

		DeviceSerialNumber
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The serial number of the equipment that produced the measurements.
A pseudonym can also be used to prevent the equipment from being
identifiable, so long as each pseudonym is unique within the dataset.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The serial number of the equipment that produced the measurements.
A pseudonym can also be used to prevent the equipment from being
identifiable, so long as each pseudonym is unique within the dataset.


		2910 more files with the same issue

		StationName
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Institution defined name of the machine that produced the measurements.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Institution defined name of the machine that produced the measurements.


		2910 more files with the same issue

		SoftwareVersions
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Manufacturer's designation of software version of the equipment that produced
the measurements.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Manufacturer's designation of software version of the equipment that produced
the measurements.


		2910 more files with the same issue

		ReceiveCoilName
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Information describing the receiver coil.
Corresponds to DICOM Tag 0018, 1250 `Receive Coil Name`,
although not all vendors populate that DICOM Tag,
in which case this field can be derived from an appropriate
private DICOM field.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Information describing the receiver coil.
Corresponds to DICOM Tag 0018, 1250 `Receive Coil Name`,
although not all vendors populate that DICOM Tag,
in which case this field can be derived from an appropriate
private DICOM field.


		2132 more files with the same issue

		ReceiveCoilActiveElements
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Information describing the active/selected elements of the receiver coil.
This does not correspond to a tag in the DICOM ontology.
The vendor-defined terminology for active coil elements can go in this field.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Information describing the active/selected elements of the receiver coil.
This does not correspond to a tag in the DICOM ontology.
The vendor-defined terminology for active coil elements can go in this field.


		2910 more files with the same issue

		GradientSetType
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: It should be possible to infer the gradient coil from the scanner model.
If not, for example because of a custom upgrade or use of a gradient
insert set, then the specifications of the actual gradient coil should be
reported independently.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: It should be possible to infer the gradient coil from the scanner model.
If not, for example because of a custom upgrade or use of a gradient
insert set, then the specifications of the actual gradient coil should be
reported independently.


		2910 more files with the same issue

		MRTransmitCoilSequence
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: This is a relevant field if a non-standard transmit coil is used.
Corresponds to DICOM Tag 0018, 9049 `MR Transmit Coil Sequence`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: This is a relevant field if a non-standard transmit coil is used.
Corresponds to DICOM Tag 0018, 9049 `MR Transmit Coil Sequence`.


		2910 more files with the same issue

		MatrixCoilMode
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: (If used)
A method for reducing the number of independent channels by combining in
analog the signals from multiple coil elements.
There are typically different default modes when using un-accelerated or
accelerated (for example, `"GRAPPA"`, `"SENSE"`) imaging.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: (If used)
A method for reducing the number of independent channels by combining in
analog the signals from multiple coil elements.
There are typically different default modes when using un-accelerated or
accelerated (for example, `"GRAPPA"`, `"SENSE"`) imaging.


		2910 more files with the same issue

		CoilCombinationMethod
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Almost all fMRI studies using phased-array coils use root-sum-of-squares
(rSOS) combination, but other methods exist.
The image reconstruction is changed by the coil combination method
(as for the matrix coil mode above),
so anything non-standard should be reported.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Almost all fMRI studies using phased-array coils use root-sum-of-squares
(rSOS) combination, but other methods exist.
The image reconstruction is changed by the coil combination method
(as for the matrix coil mode above),
so anything non-standard should be reported.


		2910 more files with the same issue

		PulseSequenceType
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: A general description of the pulse sequence used for the scan.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: A general description of the pulse sequence used for the scan.


		2132 more files with the same issue

		ScanningSequence
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Description of the type of data acquired.
Corresponds to DICOM Tag 0018, 0020 `Scanning Sequence`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Description of the type of data acquired.
Corresponds to DICOM Tag 0018, 0020 `Scanning Sequence`.


		2910 more files with the same issue

		SequenceVariant
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Variant of the ScanningSequence.
Corresponds to DICOM Tag 0018, 0021 `Sequence Variant`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Variant of the ScanningSequence.
Corresponds to DICOM Tag 0018, 0021 `Sequence Variant`.


		2910 more files with the same issue

		ScanOptions
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Parameters of ScanningSequence.
Corresponds to DICOM Tag 0018, 0022 `Scan Options`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Parameters of ScanningSequence.
Corresponds to DICOM Tag 0018, 0022 `Scan Options`.


		2910 more files with the same issue

		SequenceName
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Manufacturer's designation of the sequence name.
Corresponds to DICOM Tag 0018, 0024 `Sequence Name`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Manufacturer's designation of the sequence name.
Corresponds to DICOM Tag 0018, 0024 `Sequence Name`.


		2910 more files with the same issue

		PulseSequenceDetails
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Information beyond pulse sequence type that identifies the specific pulse
sequence used (for example,
`"Standard Siemens Sequence distributed with the VB17 software"`,
`"Siemens WIP ### version #.##,"` or
`"Sequence written by X using a version compiled on MM/DD/YYYY"`).

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Information beyond pulse sequence type that identifies the specific pulse
sequence used (for example,
`"Standard Siemens Sequence distributed with the VB17 software"`,
`"Siemens WIP ### version #.##,"` or
`"Sequence written by X using a version compiled on MM/DD/YYYY"`).


		2910 more files with the same issue

		MTState
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Boolean stating whether the magnetization transfer pulse is applied.
Corresponds to DICOM Tag 0018, 9020 `Magnetization Transfer`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Boolean stating whether the magnetization transfer pulse is applied.
Corresponds to DICOM Tag 0018, 9020 `Magnetization Transfer`.


		2910 more files with the same issue

		SpoilingState
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Boolean stating whether the pulse sequence uses any type of spoiling
strategy to suppress residual transverse magnetization.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Boolean stating whether the pulse sequence uses any type of spoiling
strategy to suppress residual transverse magnetization.


		2910 more files with the same issue

		NumberShots
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The number of RF excitations needed to reconstruct a slice or volume
(may be referred to as partition).
Please mind that this is not the same as Echo Train Length which denotes the
number of k-space lines collected after excitation in a multi-echo readout.
The data type array is applicable for specifying this parameter before and
after the k-space center is sampled.
Please see
[`"NumberShots"` metadata field]\
(SPEC_ROOT/appendices/qmri.md#numbershots-metadata-field)
in the qMRI appendix for corresponding calculations.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The number of RF excitations needed to reconstruct a slice or volume
(may be referred to as partition).
Please mind that this is not the same as Echo Train Length which denotes the
number of k-space lines collected after excitation in a multi-echo readout.
The data type array is applicable for specifying this parameter before and
after the k-space center is sampled.
Please see
[`"NumberShots"` metadata field]\
(SPEC_ROOT/appendices/qmri.md#numbershots-metadata-field)
in the qMRI appendix for corresponding calculations.


		2910 more files with the same issue

		ParallelReductionFactorInPlane
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The parallel imaging (for instance, GRAPPA) factor in plane.
Use the denominator of the fraction of k-space encoded for each slice.
For example, 2 means half of k-space is encoded.
Corresponds to DICOM Tag 0018, 9069 `Parallel Reduction Factor In-plane`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The parallel imaging (for instance, GRAPPA) factor in plane.
Use the denominator of the fraction of k-space encoded for each slice.
For example, 2 means half of k-space is encoded.
Corresponds to DICOM Tag 0018, 9069 `Parallel Reduction Factor In-plane`.


		2910 more files with the same issue

		ParallelReductionFactorOutOfPlane
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The parallel imaging (for instance, GRAPPA) factor in the second phase encoding dimension of 3D sequences.
Use the denominator of the fraction of k-space encoded in the second phase encoding dimension.
For example, 2 means half of k-space is encoded.
Will typically be 1 for 2D sequences, as each slice in a 2D acquisition is usually fully encoded.
`ParallelReductionFactorOutOfPlane` should not be confused with `MultibandAccelerationFactor`,
as they imply different methods of accelerating the acquisition.
Corresponds to DICOM Tag 0018, 9155 `Parallel Reduction Factor out-of-plane`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The parallel imaging (for instance, GRAPPA) factor in the second phase encoding dimension of 3D sequences.
Use the denominator of the fraction of k-space encoded in the second phase encoding dimension.
For example, 2 means half of k-space is encoded.
Will typically be 1 for 2D sequences, as each slice in a 2D acquisition is usually fully encoded.
`ParallelReductionFactorOutOfPlane` should not be confused with `MultibandAccelerationFactor`,
as they imply different methods of accelerating the acquisition.
Corresponds to DICOM Tag 0018, 9155 `Parallel Reduction Factor out-of-plane`.


		2910 more files with the same issue

		ParallelAcquisitionTechnique
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The type of parallel imaging used (for example `"GRAPPA"`, `"SENSE"`).
Corresponds to DICOM Tag 0018, 9078 `Parallel Acquisition Technique`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The type of parallel imaging used (for example `"GRAPPA"`, `"SENSE"`).
Corresponds to DICOM Tag 0018, 9078 `Parallel Acquisition Technique`.


		2910 more files with the same issue

		PartialFourier
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The fraction of partial Fourier information collected.
Corresponds to DICOM Tag 0018, 9081 `Partial Fourier`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The fraction of partial Fourier information collected.
Corresponds to DICOM Tag 0018, 9081 `Partial Fourier`.


		2132 more files with the same issue

		PartialFourierDirection
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The direction where only partial Fourier information was collected.
Corresponds to DICOM Tag 0018, 9036 `Partial Fourier Direction`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The direction where only partial Fourier information was collected.
Corresponds to DICOM Tag 0018, 9036 `Partial Fourier Direction`.


		2910 more files with the same issue

		MixingTime
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: In the context of a stimulated- and spin-echo 3D EPI sequence for B1+ mapping
or a stimulated-echo MRS sequence,
corresponds to the interval between spin- and stimulated-echo pulses.
In the context of a diffusion-weighted double spin-echo sequence,
corresponds to the interval between two successive diffusion sensitizing
gradients, specified in seconds.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: In the context of a stimulated- and spin-echo 3D EPI sequence for B1+ mapping
or a stimulated-echo MRS sequence,
corresponds to the interval between spin- and stimulated-echo pulses.
In the context of a diffusion-weighted double spin-echo sequence,
corresponds to the interval between two successive diffusion sensitizing
gradients, specified in seconds.


		2910 more files with the same issue

		InversionTime
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The inversion time (TI) for the acquisition, specified in seconds.
Inversion time is the time after the middle of inverting RF pulse to middle
of excitation pulse to detect the amount of longitudinal magnetization.
Corresponds to DICOM Tag 0018, 0082 `Inversion Time`
(please note that the DICOM term is in milliseconds not seconds).

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The inversion time (TI) for the acquisition, specified in seconds.
Inversion time is the time after the middle of inverting RF pulse to middle
of excitation pulse to detect the amount of longitudinal magnetization.
Corresponds to DICOM Tag 0018, 0082 `Inversion Time`
(please note that the DICOM term is in milliseconds not seconds).


		2910 more files with the same issue

		DwellTime
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: Actual dwell time (in seconds) of the receiver per point in the readout
direction, including any oversampling.
For Siemens, this corresponds to DICOM field 0019, 1018 (in ns).
This value is necessary for the optional readout distortion correction of
anatomicals in the HCP Pipelines.
It also usefully provides a handle on the readout bandwidth,
which isn't captured in the other metadata tags.
Not to be confused with `"EffectiveEchoSpacing"`, and the frequent mislabeling
of echo spacing (which is spacing in the phase encoding direction) as
"dwell time" (which is spacing in the readout direction).

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: Actual dwell time (in seconds) of the receiver per point in the readout
direction, including any oversampling.
For Siemens, this corresponds to DICOM field 0019, 1018 (in ns).
This value is necessary for the optional readout distortion correction of
anatomicals in the HCP Pipelines.
It also usefully provides a handle on the readout bandwidth,
which isn't captured in the other metadata tags.
Not to be confused with `"EffectiveEchoSpacing"`, and the frequent mislabeling
of echo spacing (which is spacing in the phase encoding direction) as
"dwell time" (which is spacing in the readout direction).


		2910 more files with the same issue

		MultibandAccelerationFactor
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The multiband factor, for multiband acquisitions.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The multiband factor, for multiband acquisitions.


		2132 more files with the same issue

		B0FieldIdentifier
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The presence of this key states that this particular 3D or 4D image MAY be
used for fieldmap estimation purposes.
Each `"B0FieldIdentifier"` MUST be a unique string within one participant's tree,
shared only by the images meant to be used as inputs for the estimation of a
particular instance of the *B<sub>0</sub> field* estimation.
It is RECOMMENDED to derive this identifier from DICOM Tags, for example,
DICOM tag 0018, 1030 `Protocol Name`, or DICOM tag 0018, 0024 `Sequence Name`
when the former is not defined (for example, in GE devices.)

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The presence of this key states that this particular 3D or 4D image MAY be
used for fieldmap estimation purposes.
Each `"B0FieldIdentifier"` MUST be a unique string within one participant's tree,
shared only by the images meant to be used as inputs for the estimation of a
particular instance of the *B<sub>0</sub> field* estimation.
It is RECOMMENDED to derive this identifier from DICOM Tags, for example,
DICOM tag 0018, 1030 `Protocol Name`, or DICOM tag 0018, 0024 `Sequence Name`
when the former is not defined (for example, in GE devices.)


		1934 more files with the same issue

		InstitutionName
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The name of the institution in charge of the equipment that produced the
measurements.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The name of the institution in charge of the equipment that produced the
measurements.


		2910 more files with the same issue

		InstitutionAddress
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The address of the institution in charge of the equipment that produced the
measurements.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The address of the institution in charge of the equipment that produced the
measurements.


		2910 more files with the same issue

		InstitutionalDepartmentName
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz - Field description: The department in the institution in charge of the equipment that produced
the measurements.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The department in the institution in charge of the equipment that produced
the measurements.


		2910 more files with the same issue

		EffectiveEchoSpacing
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: The "effective" sampling interval, specified in seconds,
between lines in the phase-encoding direction,
defined based on the size of the reconstructed image in the phase direction.
It is frequently, but incorrectly, referred to as "dwell time"
(see the `"DwellTime"` parameter for actual dwell time).
It is required for unwarping distortions using field maps.
Note that beyond just in-plane acceleration,
a variety of other manipulations to the phase encoding need to be accounted
for properly, including partial fourier, phase oversampling,
phase resolution, phase field-of-view and interpolation.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-02_phasediff.nii.gz - Field description: The "effective" sampling interval, specified in seconds,
between lines in the phase-encoding direction,
defined based on the size of the reconstructed image in the phase direction.
It is frequently, but incorrectly, referred to as "dwell time"
(see the `"DwellTime"` parameter for actual dwell time).
It is required for unwarping distortions using field maps.
Note that beyond just in-plane acceleration,
a variety of other manipulations to the phase encoding need to be accounted
for properly, including partial fourier, phase oversampling,
phase resolution, phase field-of-view and interpolation.


		1356 more files with the same issue

		TotalReadoutTime
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz - Field description: This is actually the "effective" total readout time,
defined as the readout duration, specified in seconds,
that would have generated data with the given level of distortion.
It is NOT the actual, physical duration of the readout train.
If `"EffectiveEchoSpacing"` has been properly computed,
it is just `EffectiveEchoSpacing * (ReconMatrixPE - 1)`.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-02_phasediff.nii.gz - Field description: This is actually the "effective" total readout time,
defined as the readout duration, specified in seconds,
that would have generated data with the given level of distortion.
It is NOT the actual, physical duration of the readout train.
If `"EffectiveEchoSpacing"` has been properly computed,
it is just `EffectiveEchoSpacing * (ReconMatrixPE - 1)`.


		2134 more files with the same issue

		EchoTime
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-02_phasediff.nii.gz - Field description: The echo time (TE) for the acquisition, specified in seconds.
Corresponds to DICOM Tag 0018, 0081 `Echo Time`
(please note that the DICOM term is in milliseconds not seconds).
The data type number may apply to files from any MRI modality concerned with
a single value for this field, or to the files in a
[file collection](SPEC_ROOT/appendices/file-collections.md)
where the value of this field is iterated using the
[`echo` entity](SPEC_ROOT/appendices/entities.md#echo).

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_phasediff.nii.gz - Field description: The echo time (TE) for the acquisition, specified in seconds.
Corresponds to DICOM Tag 0018, 0081 `Echo Time`
(please note that the DICOM term is in milliseconds not seconds).
The data type number may apply to files from any MRI modality concerned with
a single value for this field, or to the files in a
[file collection](SPEC_ROOT/appendices/file-collections.md)
where the value of this field is iterated using the
[`echo` entity](SPEC_ROOT/appendices/entities.md#echo).


		580 more files with the same issue

		Manufacturer
		/sub-010114/ses-02/anat/sub-010114_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Manufacturer of the equipment that produced the measurements.

		/sub-010113/ses-02/anat/sub-010113_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Manufacturer of the equipment that produced the measurements.


		193 more files with the same issue

		ManufacturersModelName
		/sub-010114/ses-02/anat/sub-010114_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Manufacturer's model name of the equipment that produced the measurements.

		/sub-010113/ses-02/anat/sub-010113_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Manufacturer's model name of the equipment that produced the measurements.


		193 more files with the same issue

		MagneticFieldStrength
		/sub-010114/ses-02/anat/sub-010114_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Nominal field strength of MR magnet in Tesla.
Corresponds to DICOM Tag 0018, 0087 `Magnetic Field Strength`.

		/sub-010113/ses-02/anat/sub-010113_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Nominal field strength of MR magnet in Tesla.
Corresponds to DICOM Tag 0018, 0087 `Magnetic Field Strength`.


		193 more files with the same issue

		PhaseEncodingDirection
		/sub-010114/ses-02/anat/sub-010114_ses-02_acq-mp2rage_T1w.nii.gz - Field description: The letters `i`, `j`, `k` correspond to the first, second and third axis of
the data in the NIFTI file.
The polarity of the phase encoding is assumed to go from zero index to
maximum index unless `-` sign is present
(then the order is reversed - starting from the highest index instead of
zero).
`PhaseEncodingDirection` is defined as the direction along which phase is was
modulated which may result in visible distortions.
Note that this is not the same as the DICOM term
`InPlanePhaseEncodingDirection` which can have `ROW` or `COL` values.

		/sub-010113/ses-02/anat/sub-010113_ses-02_acq-mp2rage_T1w.nii.gz - Field description: The letters `i`, `j`, `k` correspond to the first, second and third axis of
the data in the NIFTI file.
The polarity of the phase encoding is assumed to go from zero index to
maximum index unless `-` sign is present
(then the order is reversed - starting from the highest index instead of
zero).
`PhaseEncodingDirection` is defined as the direction along which phase is was
modulated which may result in visible distortions.
Note that this is not the same as the DICOM term
`InPlanePhaseEncodingDirection` which can have `ROW` or `COL` values.


		193 more files with the same issue

BIDS validator output (continued):

		FlipAngle
		/sub-010114/ses-02/anat/sub-010114_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Flip angle (FA) for the acquisition, specified in degrees.
Corresponds to: DICOM Tag 0018, 1314 `Flip Angle`.
The data type number may apply to files from any MRI modality concerned with
a single value for this field, or to the files in a
[file collection](SPEC_ROOT/appendices/file-collections.md)
where the value of this field is iterated using the
[`flip` entity](SPEC_ROOT/appendices/entities.md#flip).

		/sub-010113/ses-02/anat/sub-010113_ses-02_acq-mp2rage_T1w.nii.gz - Field description: Flip angle (FA) for the acquisition, specified in degrees.
Corresponds to: DICOM Tag 0018, 1314 `Flip Angle`.
The data type number may apply to files from any MRI modality concerned with
a single value for this field, or to the files in a
[file collection](SPEC_ROOT/appendices/file-collections.md)
where the value of this field is iterated using the
[`flip` entity](SPEC_ROOT/appendices/entities.md#flip).


		193 more files with the same issue

		NumberOfVolumesDiscardedByScanner
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: Number of volumes ("dummy scans") discarded by the scanner
(as opposed to those discarded by the user post hoc)
before saving the imaging file.
For example, a sequence that automatically discards the first 4 volumes
before saving would have this field as 4.
A sequence that does not discard dummy scans would have this set to 0.
Please note that the onsets recorded in the `events.tsv` file should always
refer to the beginning of the acquisition of the first volume in the
corresponding imaging file - independent of the value of
`"NumberOfVolumesDiscardedByScanner"` field.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: Number of volumes ("dummy scans") discarded by the scanner
(as opposed to those discarded by the user post hoc)
before saving the imaging file.
For example, a sequence that automatically discards the first 4 volumes
before saving would have this field as 4.
A sequence that does not discard dummy scans would have this set to 0.
Please note that the onsets recorded in the `events.tsv` file should always
refer to the beginning of the acquisition of the first volume in the
corresponding imaging file - independent of the value of
`"NumberOfVolumesDiscardedByScanner"` field.


		776 more files with the same issue

		NumberOfVolumesDiscardedByUser
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: Number of volumes ("dummy scans") discarded by the user before including the
file in the dataset.
If possible, including all of the volumes is strongly recommended.
Please note that the onsets recorded in the `events.tsv` file should always
refer to the beginning of the acquisition of the first volume in the
corresponding imaging file - independent of the value of
`"NumberOfVolumesDiscardedByUser"` field.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: Number of volumes ("dummy scans") discarded by the user before including the
file in the dataset.
If possible, including all of the volumes is strongly recommended.
Please note that the onsets recorded in the `events.tsv` file should always
refer to the beginning of the acquisition of the first volume in the
corresponding imaging file - independent of the value of
`"NumberOfVolumesDiscardedByUser"` field.


		776 more files with the same issue

		DelayTime
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: User specified time (in seconds) to delay the acquisition of data for the
following volume.
If the field is not present it is assumed to be set to zero.
Corresponds to Siemens CSA header field `lDelayTimeInTR`.
This field is REQUIRED for sparse sequences using the `"RepetitionTime"` field
that do not have the `"SliceTiming"` field set to allowed for accurate
calculation of "acquisition time".
This field is mutually exclusive with `"VolumeTiming"`.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: User specified time (in seconds) to delay the acquisition of data for the
following volume.
If the field is not present it is assumed to be set to zero.
Corresponds to Siemens CSA header field `lDelayTimeInTR`.
This field is REQUIRED for sparse sequences using the `"RepetitionTime"` field
that do not have the `"SliceTiming"` field set to allowed for accurate
calculation of "acquisition time".
This field is mutually exclusive with `"VolumeTiming"`.


		776 more files with the same issue

		AcquisitionDuration
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: Duration (in seconds) of volume acquisition.
Corresponds to DICOM Tag 0018, 9073 `Acquisition Duration`.
This field is mutually exclusive with `"RepetitionTime"`.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: Duration (in seconds) of volume acquisition.
Corresponds to DICOM Tag 0018, 9073 `Acquisition Duration`.
This field is mutually exclusive with `"RepetitionTime"`.


		776 more files with the same issue

		DelayAfterTrigger
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: Duration (in seconds) from trigger delivery to scan onset.
This delay is commonly caused by adjustments and loading times.
This specification is entirely independent of
`"NumberOfVolumesDiscardedByScanner"` or `"NumberOfVolumesDiscardedByUser"`,
as the delay precedes the acquisition.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: Duration (in seconds) from trigger delivery to scan onset.
This delay is commonly caused by adjustments and loading times.
This specification is entirely independent of
`"NumberOfVolumesDiscardedByScanner"` or `"NumberOfVolumesDiscardedByUser"`,
as the delay precedes the acquisition.


		776 more files with the same issue

		TaskDescription
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: Longer description of the task.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: Longer description of the task.


		776 more files with the same issue

		CogPOID
		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-PA_run-02_bold.nii.gz - Field description: [URI](SPEC_ROOT/common-principles.md#uniform-resource-indicator)
of the corresponding [CogPO](http://www.cogpo.org/) term.

		/sub-010114/ses-02/func/sub-010114_ses-02_task-rest_acq-AP_run-01_bold.nii.gz - Field description: [URI](SPEC_ROOT/common-principles.md#uniform-resource-indicator)
of the corresponding [CogPO](http://www.cogpo.org/) term.


		776 more files with the same issue

	Please visit https://neurostars.org/search?q=SIDECAR_KEY_RECOMMENDED for existing conversations about this issue.

	[WARNING] TOO_FEW_AUTHORS The 'Authors' field of 'dataset_description.json' should contain an array of values -
with one author per value.
This was triggered based on the presence of only one author field.
Please ignore if all contributors are already properly listed.

		/dataset_description.json

	Please visit https://neurostars.org/search?q=TOO_FEW_AUTHORS for existing conversations about this issue.

	[WARNING] NO_AUTHORS The Authors field of dataset_description.json should contain an array of fields -
with one author per field. This was triggered because there are no authors, which
will make DOI registration from dataset metadata impossible.

		Authors
		/dataset_description.json - Field description: List of individuals who contributed to the creation/curation of the dataset.


	Please visit https://neurostars.org/search?q=NO_AUTHORS for existing conversations about this issue.

	[WARNING] TSV_ADDITIONAL_COLUMNS_UNDEFINED A TSV file has extra columns which are not defined in its associated JSON sidecar
		gender
		/participants.tsv

		age..5.year.bins.
		/participants.tsv

	Please visit https://neurostars.org/search?q=TSV_ADDITIONAL_COLUMNS_UNDEFINED for existing conversations about this issue.

	[WARNING] GZIP_HEADER_MTIME The gzip header contains a non-zero timestamp.
This may leak sensitive information or indicate a non-reproducible conversion process.

		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-SEfmap02_dir-AP_epi.nii.gz
		/sub-010114/ses-02/fmap/sub-010114_ses-02_acq-GEfmap_run-01_magnitude1.nii.gz

		2046 more files with the same issue

	Please visit https://neurostars.org/search?q=GZIP_HEADER_MTIME for existing conversations about this issue.


          Summary:                           Available Tasks:        Available Modalities:
          5828 Files, 256 GB                 Rest                    MRI                  
          196 - Subjects 1 - Sessions                                                     

	If you have any questions, please post on https://neurostars.org/tags/bids.

Hi @Phil,

It doesn’t look like you have TotalReadoutTime defined in your jsons.

Best,
Steven

Thanks, @Steven. I was able to resolve this issue without defining the TotalReadoutTime in the jsons. (I might be able to calculate TotalReadoutTime if needed, but I’m not 100% sure I have all the parameters for the calculations. Stopped looking when I resolved the distortion correction issue.)

Here’s what I did.

  1. Based on this thread, I changed the DatasetType from “derivative” to “raw” in dataset_description.json. This didn’t solve the issue for me right away, but it’s possible it interacted with the following steps to solve the issue.

  2. I added the B0FieldIdentifer field to the fmap phasediff json files and B0FieldSource to the corresponding BOLD json file (as described above). This was a necessary step, but did not solve the issue on its own.

  3. I added the --use-syn-sdc and --force syn-sdc flags to the fmriprep command. This solved the issue! And notably, when the B0FieldIdentifer and B0FieldSource fields were properly set in the json files, the distortion correction method applied was not the synthetic field map-less method but the phase difference method. For example, I ran one subject with the syn-sdc flags but without the B0Field fields set. For this subject, fMRIPrep used the synthetic method (with ‘auto’ field maps). In contrast, I also ran several subjects with the syn-sdc flags and with the B0Field fields set. For these subjects, fMRIPrep used the phase difference method (with ‘phasediff’ field maps). Also notably, fMRIPrep only ran distortion correction when I used both the --use-syn-sdc and --force syn-sdc flags, but not when I only used the --use-syn-sdc flag. I’m not sure why this is, but that’s the way it worked out.

I’m using fMRIPrep v25.0.0.

Thanks again for your prompt help, @Steven!

Hi @Phil,

This might be related to @gerardyu’s issue (fMRIPrep 25.0.0 failed to use fmaps in ds004630), looks like 25.0.0 phasediff fmaps are not being incorporated correclty.

Best,
Steven

Good to know I’m not the only one. Thanks again.

We’ve opened an issue here: fmaps ignored in ds004630 · Issue #490 · nipreps/sdcflows · GitHub

Hi @Phil,

So we made some discoveries on @gerardyu 's related issue, maybe they’ll apply to you?

Make sure your phasediff and magnitude jsons ALL have the SAME B0FieldIdentifier tag within a subject. So each of them might be something like sub-x_phasediff_fmap.

Best,
Steven