Siemens Diffusion Phase Encoding Directionality #12
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By @ neurolabusc on October 27, 2021, 4:23pm Since you refer to the CSA header, I assume this Prisma is running V* (e.g. VE11C) not X* (e.g. XA30). You can get DICOMs for validating phase encoding polarity here. Specifically, the last characters of the protocol name reveal phase encoding direction (e.g. dcm2niix uses the CSA tag You can use the logorrheic vebosity (-v 2) to see how dcm2niix sees the DICOM header. This is very extensive, so you may want to apply it to a single DICOM file rather than an entire sessions. The minimal call would be For Siemens X* series (enhanced DICOM, without the CSA header), you will want to read the private DICOM tag PhaseEncodingDirectionPositiveSiemens 0021,111C. See dcm_qa_enh for sample datasets. |
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By @ baratzz on October 27, 2021, 3:11pm
Hi all,
I'm trying to determine the phase encoding directionality for some diffusion-weighted scans acquired by a Siemens Prisma scanner. dcm2niix (@ neurolabusc) seems to determine phase encoding smoothly, however, looking at the private tags, I couldn't find the private tag (0019, 100e) or any other tag that adequately differentiates the two.
Looking deeper into the Series' CSA header revealed some differences under the "Diffusion" tag, however, I could not determine with confidence which of these differences is a reliable source for deducing the directionality. E.g. for an AP-encoded series:
and for a PA-encoded series:
Any help figuring this out will be greatly appreciated!
Best,
Zvi
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