dcmpmap: a library for working with parametric map objects

This module contains classes to create, load, access and store DICOM Parametric Map objects, which have originally been introduced to the DICOM standard with Supplement 172 in 2014.

In the standard, the data inside each Parametric Map object must rely on one of these data types:

• 16 bit unsigned integer
• 16 bit signed integer
• 32 bit floating point
• 64 bit floating point

All of them are supported by the dcmpmap library.

The main class of this module is:

• DPMParametricMapIOD

This module makes heavy use of the dcmiod module for managing common IOD attributes and the dcmfg module for functional group support. Read the "Examples" sections for more explanations.

Examples

The following two examples show:

• How to access and dump information (including the binary data values) from a Parametric Map object
• and how to use the API to create such an object yourself.

Dumping information from Parametric Map

The Parametric Map class uses a template in order to instantiate the correct pixel data type internally, and to offer a dedicated API for that type. Allowed types are Uint16, Sint16, Float32 and Float64.

Since internally the data types are handled in a C++ Variant, the usual concept to "switch" between these types in code is to use a Visitor which overloads the operator "()" for each data type that can occur in the Variant. This concept is also demonstrated below where the type of pixel data is printed.

The rest of the code uses the API of the dcmiod and dcmfg module in order to get basic information about Patient, Study, Series and Instance, as well as functional group information, especially the Real World Value Mapping defined in the file.

#include "dcmtk/config/osconfig.h"    /* make sure OS specific configuration is included first */
#include "dcmtk/dcmpmap/dpmparametricmapiod.h"
 
static void dumpRWVM(const unsigned long frameNumber,
                     FGInterface& fg)
{
  FGRealWorldValueMapping* rw = OFstatic_cast(FGRealWorldValueMapping*, fg.get(frameNumber, DcmFGTypes::EFG_REALWORLDVALUEMAPPING));
  if (rw)
  {
    size_t numMappings = rw->getRealWorldValueMapping().size();
    COUT << "  Number of Real World Value Mappings defined: " << numMappings << OFendl;
    for (size_t m = 0; m < numMappings; m++)
    {
      FGRealWorldValueMapping::RWVMItem* item = rw->getRealWorldValueMapping()[m];
      OFString label, expl;
      item->getLUTLabel(label);
      item->getLUTExplanation(expl);
      COUT << "    RWVM Mapping #" << m << ":" << OFendl;
      COUT << "      LUT Label: << " << label << OFendl;
      COUT << "      LUT Explanation: " << expl << OFendl;
      COUT << "      Measurement Units Code: " << item->getMeasurementUnitsCode().toString() << OFendl;
      size_t numQuant = item->getEntireQuantityDefinitionSequence().size();
      if (numQuant > 0)
      {
        COUT << "    Number of Quantities defined: " << numQuant << OFendl;
        for (size_t q = 0; q < numQuant; q++)
        {
          ContentItemMacro* macro = item->getEntireQuantityDefinitionSequence()[q];
          COUT << "      Quantity #" << q << ": " << macro->toString() << OFendl;
        }
      }
    }
  }
  else
  {
    CERR << "  Error: No Real World Value Mappings defined for frame #" << frameNumber << OFendl;
  }
}
 
class DumpFramesVisitor
{
public:
 
  DumpFramesVisitor(DPMParametricMapIOD* map,
                    const unsigned long numPerFrame)
  : m_Map(map)
  , m_numPerFrame(numPerFrame)
  {
  }
 
  template<typename T>
  OFBool operator()(DPMParametricMapIOD::Frames<T>& frames)
  {
    dumpDataType(frames);
    for (unsigned long f = 0; f < m_Map->getNumberOfFrames(); f++)
    {
      COUT << "Dumping info of frame #" << f << ":" << OFendl;
      FGInterface& fg = m_Map->getFunctionalGroups();
      dumpRWVM(f, fg);
      COUT << "Dumping data for frame #" << f << ": " << OFendl;
      T* frame = frames.getFrame(f);
      for (unsigned long p = 0; p < m_numPerFrame; p++)
      {
        COUT << frame[p] << " ";
      }
      COUT << OFendl << OFendl;
    }
    return 0;
  }
 
  OFBool operator()(OFCondition& cond)
  {
    // Avoid compiler warning
    (void)cond;
    CERR << "Type of data samples not supported" << OFendl;
    return OFFalse;
  }
 
  OFBool dumpHeader(DPMParametricMapIOD::Frames<Float32>& frames)
  {
    // Avoid compiler warning
    (void)frames;
    COUT << "File has 32 Bit float data" << OFendl;
    return OFFalse;
  }
 
  OFBool dumpHeader(DPMParametricMapIOD::Frames<Uint16>& frames)
  {
    // Avoid compiler warning
    (void)frames;
    COUT << "File has 16 Bit unsigned integer data" << OFendl;
    return OFFalse;
  }
 
  OFBool dumpHeader(DPMParametricMapIOD::Frames<Sint16>& frames)
  {
    // Avoid compiler warning
    (void)frames;
    COUT << "File has 16 Bit signed integer data" << OFendl;
    return OFFalse;
  }
 
  OFBool dumpHeader(DPMParametricMapIOD::Frames<Float64>& frames)
  {
    // Avoid compiler warning
    (void)frames;
    COUT << "File has 64 Bit float data" << OFendl;
    return OFTrue;
  }
 
  template<typename T>
  OFBool dumpDataType(DPMParametricMapIOD::Frames<T>& frames)
  {
    // Avoid compiler warning
    (void)frames;
    CERR << "Type of data samples not supported" << OFendl;
    return OFFalse;
  }
 
  DPMParametricMapIOD* m_Map;
  unsigned long m_numPerFrame;
 
};
 
 
static void dumpGeneral(DPMParametricMapIOD& map)
{
  OFString patName, patID, studyUID, studyDate, seriesUID, modality, sopUID;
  map.getPatient().getPatientName(patName);
  map.getPatient().getPatientID(patID);
  map.getStudy().getStudyInstanceUID(studyUID);
  map.getStudy().getStudyDate(studyDate);
  map.getSeries().getSeriesInstanceUID(seriesUID);
  map.getSeries().getModality(modality);
  map.getSOPCommon().getSOPInstanceUID(sopUID);
  COUT << "Patient Name       : " << patName << OFendl;
  COUT << "Patient ID         : " << patID << OFendl;
  COUT << "Study Instance UID : " << studyUID << OFendl;
  COUT << "Study Date         : " << studyDate << OFendl;
  COUT << "Series Instance UID: " << seriesUID << OFendl;
  COUT << "SOP Instance UID   : " << sopUID << OFendl;
  COUT << "---------------------------------------------------------------" << OFendl;
  OFBool isPerFrame;
  map.getFunctionalGroups().get(0, DcmFGTypes::EFG_REALWORLDVALUEMAPPING, isPerFrame);
  if (isPerFrame)
  {
    COUT << "Real World Value Mapping: Defined per-frame" << OFendl;
  }
  else
  {
    COUT << "Real World Value Mapping: Defined shared (i.e. single definition for all frames):" << OFendl;
  }
  COUT << "---------------------------------------------------------------" << OFendl;
}
 
 
int main (int argc, char* argv[])
{
  // OFLog::configure(OFLogger::DEBUG_LOG_LEVEL);
  OFString inputFile;
  if (argc < 2)
  {
    CERR << "Usage: dump_pmp <input-file>" << std::endl;
    return 1;
  }
  else
  {
    inputFile = argv[1];
    if (!OFStandard::fileExists(inputFile))
    {
      CERR << "Input file " << inputFile << " does not exist " << OFendl;
      return 1;
    }
  }
 
  OFvariant<OFCondition,DPMParametricMapIOD*> result = DPMParametricMapIOD::loadFile(inputFile);
  if (OFget<DPMParametricMapIOD*>(&result))
  {
    DPMParametricMapIOD* map = *OFget<DPMParametricMapIOD*>(&result);
    dumpGeneral(*map);
    COUT << "Dumping #" << map->getNumberOfFrames() << " frames of file " << inputFile << OFendl;
    Uint16 rows, cols = 0;
    map->getRows(rows);
    map->getColumns(cols);
    unsigned long numPerFrame = rows * cols;
    DPMParametricMapIOD::FramesType frames = map->getFrames();
    OFvisit<OFBool>(DumpFramesVisitor(map, numPerFrame), frames);
  }
  else
  {
    CERR << "Could not load parametric map: " << (*OFget<OFCondition>(&result)).text() << OFendl;
    exit(1);
  }
  exit(0);
}

Creation of Parametric Maps

The Parametric Map class uses a template in order to instantiate the correct pixel data type internally, and to offer a dedicated API for that type. Allowed types are Uint16, Sint16, Float32 and Float64. The example below demonstrates that the API use is generally the same for all types.

The procedure in the example (and most of it applies for the general case) is as follows:

• The main() routine calls test_pmap() four times, each time using a different Image Pixel Module as template parameter which makes sure that the right pixel data type is used within the created Parametric Map.
• test_pmap() demonstrates the overall steps to create the map:
• Create a new Parametric Map by calling DPMParametricMapIOD::create() (via create_pmap()), and then
• add shared functional groups,
• add dimensions,
• and add frames with the related per-frame functional groups to the object.
• Finally, general data regarding Patient and Study is set.
• Note that the order of these steps in test_pmap() does not matter.

Per default, DPMParametricMapIOD::create() creates a new DICOM instance, within a brand-new DICOM Series that belongs to a brand-new DICOM Study. All minimal information for Patient, Study and Series will be set (e.g. Study, Series and SOP Instance UID as well as other information that is handed over to the create() call, like Series Number). Patient Name and ID are left empty per default.

Of course, often you might want to put the new instance into an existing Series instead, or place the brand-new Series into an existing Study or at least assign it to an existing Patient. The easiest way to to do that is to use the call import() that imports Patient or even Study, Series and Frame of Reference information from an existing file, i.e. place it under an existing Patient, Study and/or Series.

When adding information to the Parametric Map using the public API, some basic checks are usually performed on the data. Finally, when calling saveFile(), some further checks take place, e.g. validating the structure of the functional groups or making sure that all required element values are set.

#include "dcmtk/config/osconfig.h"    /* make sure OS specific configuration is included first */
 
#include "dcmtk/ofstd/oftest.h"
#include "dcmtk/dcmiod/iodutil.h"
#include "dcmtk/dcmpmap/dpmparametricmapiod.h"
#include "dcmtk/dcmfg/fgpixmsr.h"
#include "dcmtk/dcmfg/fgplanpo.h"
#include "dcmtk/dcmfg/fgplanor.h"
#include "dcmtk/dcmfg/fgfracon.h"
#include "dcmtk/dcmfg/fgframeanatomy.h"
#include "dcmtk/dcmfg/fgidentpixeltransform.h"
#include "dcmtk/dcmfg/fgframevoilut.h"
#include "dcmtk/dcmfg/fgrealworldvaluemapping.h"
#include "dcmtk/dcmfg/fgparametricmapframetype.h"
 
const size_t NUM_FRAMES = 10;
const Uint16 ROWS = 10;
const Uint16 COLS = 10;
const unsigned long NUM_VALUES_PER_FRAME = ROWS * COLS;
 
 
// Set Patient and Study example data
static void setGenericData(DPMParametricMapIOD& map)
{
  map.getPatient().setPatientName("Onken^Michael");
  map.getPatient().setPatientID("007");
  map.getStudy().setStudyDate("20160721");
  map.getStudy().setStudyTime("111200");
  map.getStudy().setStudyID("4711");
}
 
 
// Create Parametric Map
template<typename ImagePixel>
static OFvariant<OFCondition,DPMParametricMapIOD> create_pmap()
{
  return DPMParametricMapIOD::create<ImagePixel>
  (
    "MR",                 // Modality
    "1",                  // Series Number
    "1",                  // Instance Number
    ROWS,
    COLS,
    IODEnhGeneralEquipmentModule::EquipmentInfo("Open Connections GmbH", "make_pmp", "SN_0815", "0.1"),
    ContentIdentificationMacro("1", "PARAMAP_LABEL", "Example description from test program", "Onken^Michael"),
    "VOLUME",             // Image Flavor
    "MTT",                // Derived Pixel Contrast
    DPMTypes::CQ_RESEARCH // Content Qualification
  );
}
 
 
// Add those functional groups that are common for all frames
static OFCondition addSharedFunctionalGroups(DPMParametricMapIOD& map)
{
  FGPixelMeasures pixelMeasures;
  pixelMeasures.setPixelSpacing("1\\1");
  pixelMeasures.setSliceThickness("0.1");
  pixelMeasures.setSpacingBetweenSlices("0.1");
  FGPlaneOrientationPatient planeOrientPatientFG;
  planeOrientPatientFG.setImageOrientationPatient("1", "0", "0", "0", "1", "0");
  FGFrameAnatomy frameAnaFG;
  frameAnaFG.setLaterality(FGFrameAnatomy::LATERALITY_UNPAIRED);
  frameAnaFG.getAnatomy().getAnatomicRegion().set("T-A0100", "SRT", "Brain");
  FGIdentityPixelValueTransformation idTransFG;
  FGParametricMapFrameType frameTypeFG;
  frameTypeFG.setFrameType("DERIVED\\PRIMARY\\VOLUME\\MTT");
 
  // Add groups to Parametric Map
  OFCondition result;
  if ((result = map.addForAllFrames(pixelMeasures)).good())
  if ((result = map.addForAllFrames(planeOrientPatientFG)).good())
  if ((result = map.addForAllFrames(frameAnaFG)).good())
  if ((result = map.addForAllFrames(idTransFG)).good())
    result = map.addForAllFrames(frameTypeFG);
 
  return result;
}
 
 
// Add a single dimension for demonstration purposes based on "Image Position Patient"
static OFCondition addDimensions(DPMParametricMapIOD& map)
{
  IODMultiframeDimensionModule& mod = map.getIODMultiframeDimensionModule();
  OFString dimUID = DcmIODUtil::createUID(0);
  OFCondition result = mod.addDimensionIndex(DCM_ImagePositionPatient, dimUID, DCM_RealWorldValueMappingSequence, "Frame position");
  return result;
}
 
 
// Add one frame to parametric map. Frame number is used to compute some
// varying example data values differing from frame to frame
template <typename PixelType>
static OFCondition addFrame(DPMParametricMapIOD& map,
                            const unsigned long frameNo)
{
  // Create example data
 
  OFVector<PixelType> data(NUM_VALUES_PER_FRAME);
  for (size_t n=0; n < data.size(); ++n)
  {
    data[n] = (n*frameNo+n) + (0.1 * (frameNo % 10));
  }
 
  Uint16 rows, cols;
  OFCondition cond = map.getImagePixel().getRows(rows);
  cond = map.getImagePixel().getColumns(cols);
 
  // Create functional groups
  OFVector<FGBase*> groups;
  OFunique_ptr<FGPlanePosPatient> fgPlanePos(new FGPlanePosPatient);
  OFunique_ptr<FGFrameContent > fgFracon(new FGFrameContent);
  OFunique_ptr<FGRealWorldValueMapping> fgRVWM(new FGRealWorldValueMapping());
  FGRealWorldValueMapping::RWVMItem* rvwmItemSimple = new FGRealWorldValueMapping::RWVMItem();
  if (!fgPlanePos  || !fgFracon || !fgRVWM || !rvwmItemSimple )
    return EC_MemoryExhausted;
 
  // Fill in functional group values
 
  // Real World Value Mapping
  rvwmItemSimple->setRealWorldValueSlope(10);
  rvwmItemSimple->setRealWorldValueIntercept(0);
  rvwmItemSimple->setDoubleFloatRealWorldValueFirstValueMapped(0.12345);
  rvwmItemSimple->setDoubleFloatRealWorldValueLastValueMapped(98.7654);
  rvwmItemSimple->getMeasurementUnitsCode().set("{counts}/s", "UCUM", "Counts per second");
  rvwmItemSimple->setLUTExplanation("We are mapping trash to junk.");
  rvwmItemSimple->setLUTLabel("Just testing");
  CodeSequenceMacro* qCodeName = new CodeSequenceMacro("G-C1C6", "SRT", "Quantity");
  CodeSequenceMacro* qSpec = new CodeSequenceMacro("110805", "SRT", "T2 Weighted MR Signal Intensity");
  ContentItemMacro* quantity = new ContentItemMacro;
  if (!quantity || !qSpec || !quantity)
    return EC_MemoryExhausted;
  quantity->getEntireConceptNameCodeSequence().push_back(qCodeName);
  quantity->getEntireConceptCodeSequence().push_back(qSpec);
  rvwmItemSimple->getEntireQuantityDefinitionSequence().push_back(quantity);
  quantity->setValueType(ContentItemMacro::VT_CODE);
  fgRVWM->getRealWorldValueMapping().push_back(rvwmItemSimple);
 
  // Plane Position
  OFStringStream ss;
  ss << frameNo;
  OFSTRINGSTREAM_GETOFSTRING(ss, framestr) // convert number to string
  fgPlanePos->setImagePositionPatient("0", "0", framestr);
 
  // Frame Content
  OFCondition result = fgFracon->setDimensionIndexValues(frameNo+1 /* value within dimension */, 0 /* first dimension */);
 
  // Add frame with related groups
  if (result.good())
  {
    // Add frame
    groups.push_back(fgPlanePos.get());
    groups.push_back(fgFracon.get());
    groups.push_back(fgRVWM.get());
    groups.push_back(fgPlanePos.get());
    DPMParametricMapIOD::FramesType frames = map.getFrames();
    result = OFget<DPMParametricMapIOD::Frames<PixelType> >(&frames)->addFrame(&*data.begin(), NUM_VALUES_PER_FRAME, groups);
  }
 
  return result;
}
 
 
// Main routine that creates Parametric Maps
template<typename ImagePixel>
static OFCondition test_pmap(const OFString& saveDestination)
{
  OFvariant<OFCondition,DPMParametricMapIOD> obj = create_pmap<ImagePixel>();
  if (OFCondition* pCondition = OFget<OFCondition>(&obj))
    return *pCondition;
 
  DPMParametricMapIOD& map = *OFget<DPMParametricMapIOD>(&obj);
 
  OFCondition result;
  if ((result = addSharedFunctionalGroups(map)).good())
  if ((result = addDimensions(map)).good())
  {
    // Add frames (parametric map data), and per-frame functional groups
    for (unsigned long f = 0; result.good() && (f < NUM_FRAMES); f++)
      result = addFrame<OFTypename ImagePixel::value_type>(map, f);
  }
 
  // Set some generic data (keep dciodvfy happy on DICOMDIR warnings)
  if (result.good())
  {
    setGenericData(map);
  }
 
  // Save
  if (result.good())
  {
    return map.saveFile(saveDestination.c_str());
  }
  else
  {
    return result;
  }
}
 
 
int main (int argc, char* argv[])
{
  OFString outputDir;
  if (argc < 2)
  {
    CERR << "Usage: make_pmp <output-dir>" << std::endl;
    return 1;
  }
  else
  {
    outputDir = argv[1];
    if (!OFStandard::dirExists(outputDir))
    {
      CERR << "Output directory " << outputDir << " does not exist " << OFendl;
      return 1;
    }
  }
 
  //OFLog::configure(OFLogger::DEBUG_LOG_LEVEL);
 
  // Test all possible parametric map types (signed and unsigned integer, floating point
  // and double floating point)
 
  test_pmap<IODImagePixelModule<Uint16> >(outputDir + "/uint_paramap.dcm");
  test_pmap<IODImagePixelModule<Sint16> >(outputDir + "/sint_paramap.dcm");
  test_pmap<IODFloatingPointImagePixelModule>(outputDir + "/float_paramap.dcm");
  test_pmap<IODDoubleFloatingPointImagePixelModule>(outputDir + "/double_paramap.dcm");
 
  return 0;
}