Dear ASL experts,
we are measuring multiple TI pcASL on a Siemens 3T Scanner with currently 10 PLDs (0.3,0.6,0.9 ... 3 s) and use asl_gui to create the perfusion maps. We also aquire M0 calibration data with a TR of 5s (5 volumes). The quantification of absolute perfusion values seems to be inaccurate though. There are values of over 100 ml per 100 g per minute for cortical areas and over 60-70 for white matter, which must certainly be too high. Additionally there are relevant variations in CBF values when measuring the same subject multiple times.
I have noticed, that the reference tissue CSF mask created automatically by asl_gui, sometimes doesn't fit the respective voxels in the M0 images. Creating a mask manually doesn't improve the results though.
I hope you can advise me on how to fix these issues.
with kind regards, Julian Schroeder
J. Schroeder, M.D.
Department of Neurology
University Medical Center Hamburg-Eppendorf
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