Howto: Load File Meta-Header
Here's an example that shows how to load the File Meta Information Header of a DICOMfile without reading the dataset. This could be useful if you are e.g. only interested in theSOP Class UID and Transfer Syntax UID of the file.
There are three different approaches:
-
Use the
loadFile()
method of theDcmMetaInfo
class. -
Use the
loadFile()
method of theDcmFileFormat
class with read modeERM_metaOnly
. -
Use the
read()
method of theDcmFileFormat
class in order to successively load the meta-header and the dataset.
The third approach allows for reading the dataset only if certain criteria (based on the data elements in the meta-header) are met. Please note that in this case the same input stream is used and that the meta-header is only read once.
Source Code
#include "dcmtk/config/osconfig.h" #include "dcmtk/dcmdata/dctk.h" #include "dcmtk/dcmdata/dcistrmf.h" int main(int argc, char *argv[]) { OFCondition status; /* approach 1 */ DcmMetaInfo metainfo; status = metainfo.loadFile("test.dcm"); if (status.good()) { OFString sopClassUID, xferUID; if (metainfo.findAndGetOFString(DCM_MediaStorageSOPClassUID, sopClassUID).good()) COUT << "SOP Class UID: " << sopClassUID << OFendl; if (metainfo.findAndGetOFString(DCM_TransferSyntaxUID, xferUID).good()) COUT << "Transfer Syntax UID: " << xferUID << OFendl; metainfo.print(COUT); } /* approach 2 */ DcmFileFormat fileformat; status = fileformat.loadFile("test.dcm", EXS_Unknown, EGL_noChange, DCM_MaxReadLength, ERM_metaOnly); if (status.good()) { OFString sopClassUID, xferUID; if (fileformat.getMetaInfo()->findAndGetOFString(DCM_MediaStorageSOPClassUID, sopClassUID).good()) COUT << "SOP Class UID: " << sopClassUID << OFendl; if (fileformat.getMetaInfo()->findAndGetOFString(DCM_TransferSyntaxUID, xferUID).good()) COUT << "Transfer Syntax UID: " << xferUID << OFendl; fileformat.print(COUT); } /* approach 3 */ fileformat.clear(); DcmInputFileStream fileStream("test.dcm"); status = fileStream.status(); if (status.good()) { /* first, read meta-header */ fileformat.setReadMode(ERM_metaOnly); fileformat.transferInit(); status = fileformat.read(fileStream); if (status.good()) { OFString sopClassUID, xferUID; if (fileformat.getMetaInfo()->findAndGetOFString(DCM_MediaStorageSOPClassUID, sopClassUID).good()) COUT << "SOP Class UID: " << sopClassUID << OFendl; if (fileformat.getMetaInfo()->findAndGetOFString(DCM_TransferSyntaxUID, xferUID).good()) COUT << "Transfer Syntax UID: " << xferUID << OFendl; /* then read dataset if certain criteria are met */ if (sopClassUID == UID_SecondaryCaptureImageStorage) { fileformat.setReadMode(ERM_autoDetect); status = fileformat.read(fileStream); if (status.good()) { fileformat.print(COUT); } } } fileformat.transferEnd(); } return 0; }
Note
Please note that the above sample code requires DCMTK 3.5.5 (20100608 or newer).