idc-index-data / mr_index_schema.json
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idc-index-data 24.2.2
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{
"table_description": "This table contains one row per MR Image Storage (SOPClassUID 1.2.840.10008.5.1.4.1.1.4) DICOM series in IDC, capturing MR acquisition and sequence parameters that are not included in the main idc_index table. The index can be joined to idc_index on SeriesInstanceUID to combine universal series metadata with MR-specific acquisition parameters. EchoTime and DiffusionBValue are reported as arrays of all distinct per-instance values because they legitimately differ across instances within multi-echo and diffusion-weighted series respectively. All other attributes are aggregated with ANY_VALUE (one representative instance).",
"columns": [
{
"name": "SeriesInstanceUID",
"type": "STRING",
"mode": "NULLABLE",
"description": "DICOM SeriesInstanceUID \u2014 unique identifier of the MR series; use to join with idc_index"
},
{
"name": "MagneticFieldStrength",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "static magnetic field strength in Tesla as defined in DICOM MagneticFieldStrength attribute; constant across instances within a series \u2014 aggregated with ANY_VALUE"
},
{
"name": "ScanningSequence",
"type": "STRING",
"mode": "REPEATED",
"description": "pulse sequence type as defined in DICOM ScanningSequence attribute (SE = Spin Echo, GR = Gradient Recalled, IR = Inversion Recovery, EP = Echo Planar); may contain multiple values; constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "SequenceVariant",
"type": "STRING",
"mode": "REPEATED",
"description": "variant of the scanning sequence as defined in DICOM SequenceVariant attribute (SK = Segmented k-Space, MTC = Magnetization Transfer Contrast, SS = Steady State, TRSS = Time Reversed Steady State, SP = Spoiled, MP = MAG Prepared, OSP = Oversampling Phase, NONE = No sequence variant); may contain multiple values; constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "MRAcquisitionType",
"type": "STRING",
"mode": "NULLABLE",
"description": "whether the acquisition is 2D or 3D as defined in DICOM MRAcquisitionType attribute; constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "EchoTime",
"type": "FLOAT",
"mode": "REPEATED",
"description": "distinct echo times in ms present in the series, derived from DICOM EchoTime attribute; aggregated as ARRAY_AGG(DISTINCT) across all instances because EchoTime legitimately varies in multi-echo sequences; single-element array for single-echo series, multi-element array for multi-echo series (e.g., [2.46, 4.92, 7.38])"
},
{
"name": "RepetitionTime",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "repetition time in ms as defined in DICOM RepetitionTime attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "EchoTrainLength",
"type": "INTEGER",
"mode": "NULLABLE",
"description": "number of echoes in the echo train as defined in DICOM EchoTrainLength attribute; constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "FlipAngle",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "flip angle in degrees as defined in DICOM FlipAngle attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "PixelBandwidth",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "receiver bandwidth per pixel in Hz as defined in DICOM PixelBandwidth attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "ImagingFrequency",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "Larmor resonance frequency in MHz as defined in DICOM ImagingFrequency attribute; proportional to MagneticFieldStrength (42.577 MHz/T for proton); constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "ImagedNucleus",
"type": "STRING",
"mode": "NULLABLE",
"description": "nucleus used for imaging as defined in DICOM ImagedNucleus attribute (e.g., 1H for proton, 31P, 23Na); constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "PixelSpacing_row_mm",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "in-plane pixel spacing along the row direction in mm, derived from DICOM PixelSpacing[0]; MR pixel spacing is isotropic in almost all series in IDC; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "PixelSpacing_col_mm",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "in-plane pixel spacing along the column direction in mm, derived from DICOM PixelSpacing[1]; MR pixel spacing is isotropic in almost all series in IDC; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "Rows",
"type": "INTEGER",
"mode": "NULLABLE",
"description": ""
},
{
"name": "Columns",
"type": "INTEGER",
"mode": "NULLABLE",
"description": ""
},
{
"name": "SliceThickness",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "nominal slice thickness in mm as defined in DICOM SliceThickness attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "InversionTime",
"type": "FLOAT",
"mode": "NULLABLE",
"description": "inversion time in ms as defined in DICOM InversionTime attribute; populated only for inversion recovery sequences, NULL otherwise; constant across instances \u2014 aggregated with ANY_VALUE"
},
{
"name": "ReceiveCoilName",
"type": "STRING",
"mode": "NULLABLE",
"description": "name of the receiver coil used as defined in DICOM ReceiveCoilName attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "SequenceName",
"type": "STRING",
"mode": "NULLABLE",
"description": "manufacturer-specific pulse sequence name as defined in DICOM SequenceName attribute (e.g., *tfl* for Siemens FLASH, *ep_b1000* for Siemens EPI diffusion); aggregated with ANY_VALUE \u2014 constant across instances within a series"
},
{
"name": "DiffusionBValue",
"type": "FLOAT",
"mode": "REPEATED",
"description": "distinct diffusion b-values in s/mm\u00b2 present in the series, derived from DICOM DiffusionBValue attribute; aggregated as ARRAY_AGG(DISTINCT) across all instances because DiffusionBValue legitimately varies across instances in diffusion-weighted series; empty array for non-DWI series; multi-element for DWI (e.g., [0.0, 1000.0])"
},
{
"name": "NumberOfTemporalPositions",
"type": "INTEGER",
"mode": "NULLABLE",
"description": "number of temporal positions (time frames) in the series as defined in DICOM NumberOfTemporalPositions attribute; populated for dynamic (DCE-MRI) series; NULL otherwise; constant across instances \u2014 aggregated with ANY_VALUE"
}
]
}