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Just as a follow up (sorry for spamming): After a bit more digging, I suspect the value comes from the private Siemens DICOM tag (0019, 1013), which for our dataset was (0,0,-1175). Other people online seem to quote theirs to be (0,0,~-1250). To hazard a guess, I think it might be the distance between the isocentre of the magnet and the end of the bed. The small difference between 1175 and 1250 could be because the spatial calibration phantom sits a little bit further up the bed than the head would be for a head scan. Kind regards, Richard On 14 Feb 2019, at 15:06, Brown, Richard <[log in to unmask]<mailto:[log in to unmask]>> wrote: Hi David, Johannes, I was trying to wrap my head around ISMRMRD geometry metadata. I re-stumbled across patient_table_position, which for the spatial calibration phantom was (0,0,11750). Looking through the siemens_to_ismrmrd source code, there are two relevant lines of code (in main.cpp): Line 1671: ismrmrd_acq->patient_table_position()[2] = (float)scanhead.lPTABPosZ; Where scanhead.lPTABPosZ is calculated here: Line 1455: scanhead.lPTABPosZ = mdh.ushPTABPosNeg;//TODO: Modify calculation The "//TODO: Modify calculation” doesn't inspire much confidence... I’ve created an issue to try and figure out if it’s a bug or actually means something: https://github.com/ismrmrd/siemens_to_ismrmrd/issues/42 Kind regards, Richard ________________________________ To unsubscribe from the CCP-PETMR-DEVEL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP-PETMR-DEVEL&A=1 ######################################################################## To unsubscribe from the CCP-PETMR-DEVEL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP-PETMR-DEVEL&A=1