ct_index_schema.json

{
  "table_description": "This table contains one row per CT Image Storage (SOPClassUID 1.2.840.10008.5.1.4.1.1.2) DICOM series in IDC, capturing acquisition and reconstruction 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 CT-specific acquisition parameters. For XRayTubeCurrent, Exposure, and ExposureTime \u2014 which vary across instances within a series due to dose modulation \u2014 both min and max values are reported. 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 CT series; use to join with idc_index"
    },
    {
      "name": "ImageType",
      "type": "STRING",
      "mode": "REPEATED",
      "description": "image type values as defined in DICOM ImageType attribute (e.g., ORIGINAL/DERIVED, PRIMARY/SECONDARY, AXIAL/LOCALIZER); aggregated with ANY_VALUE \u2014 constant across instances within a series"
    },
    {
      "name": "PixelSpacing_row_mm",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "in-plane pixel spacing along the row direction in mm, derived from DICOM PixelSpacing[0]; a subset of CT series have anisotropic spacing where this differs from PixelSpacing_col_mm; 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]; a subset of CT series have anisotropic spacing where this differs from PixelSpacing_row_mm; 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 reconstructed slice thickness in mm as defined in DICOM SliceThickness attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
    },
    {
      "name": "KVP",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "peak kilovoltage of the X-ray tube in kV as defined in DICOM KVP attribute; constant across instances \u2014 aggregated with ANY_VALUE"
    },
    {
      "name": "ScanOptions",
      "type": "STRING",
      "mode": "REPEATED",
      "description": "acquisition scan options as defined in DICOM ScanOptions attribute (e.g., HELICAL MODE, AXIAL MODE, SCOUT MODE); may contain multiple values; aggregated with ANY_VALUE \u2014 constant across instances within a series"
    },
    {
      "name": "ConvolutionKernel",
      "type": "STRING",
      "mode": "REPEATED",
      "description": "reconstruction convolution kernel as defined in DICOM ConvolutionKernel attribute; vendor-specific string (e.g., B30f, STANDARD, LUNG); may contain multiple values; aggregated with ANY_VALUE \u2014 constant across instances within a series"
    },
    {
      "name": "GantryDetectorTilt",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "nominal angle of the scanning gantry in degrees as defined in DICOM GantryDetectorTilt attribute; non-zero for gantry-tilted acquisitions; constant across instances \u2014 aggregated with ANY_VALUE"
    },
    {
      "name": "XRayTubeCurrent_min",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "minimum X-ray tube current in mA across all instances in the series, derived from DICOM XRayTubeCurrent attribute; equals XRayTubeCurrent_max for fixed-current acquisitions; lower than XRayTubeCurrent_max for dose-modulated acquisitions (MIN across all instances)"
    },
    {
      "name": "XRayTubeCurrent_max",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "maximum X-ray tube current in mA across all instances in the series, derived from DICOM XRayTubeCurrent attribute; equals XRayTubeCurrent_min for fixed-current acquisitions; higher than XRayTubeCurrent_min for dose-modulated acquisitions (MAX across all instances)"
    },
    {
      "name": "FilterType",
      "type": "STRING",
      "mode": "NULLABLE",
      "description": "type of filter used in the acquisition as defined in DICOM FilterType attribute (e.g., WEDGE, BUTTERFLY, FLAT); constant across instances \u2014 aggregated with ANY_VALUE"
    },
    {
      "name": "Exposure_min",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "minimum exposure in mAs across all instances in the series, derived from DICOM Exposure attribute; equals Exposure_max for fixed-exposure acquisitions; lower than Exposure_max for dose-modulated acquisitions (MIN across all instances)"
    },
    {
      "name": "Exposure_max",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "maximum exposure in mAs across all instances in the series, derived from DICOM Exposure attribute; equals Exposure_min for fixed-exposure acquisitions; higher than Exposure_min for dose-modulated acquisitions (MAX across all instances)"
    },
    {
      "name": "ExposureTime_min",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "minimum duration of the X-ray exposure in ms across all instances in the series, derived from DICOM ExposureTime attribute (MIN across all instances)"
    },
    {
      "name": "ExposureTime_max",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "maximum duration of the X-ray exposure in ms across all instances in the series, derived from DICOM ExposureTime attribute (MAX across all instances)"
    },
    {
      "name": "DataCollectionDiameter",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "diameter of the region over which data were collected in mm as defined in DICOM DataCollectionDiameter attribute; constant across instances \u2014 aggregated with ANY_VALUE"
    },
    {
      "name": "ReconstructionDiameter",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "diameter of the reconstruction field of view in mm as defined in DICOM ReconstructionDiameter attribute; aggregated with ANY_VALUE \u2014 constant across instances within a series"
    },
    {
      "name": "SpiralPitchFactor",
      "type": "FLOAT",
      "mode": "NULLABLE",
      "description": "ratio of the beam pitch for helical CT as defined in DICOM SpiralPitchFactor attribute; NULL for non-helical (sequential/axial) acquisitions; constant across instances \u2014 aggregated with ANY_VALUE"
    }
  ]
}