Dear BASIL experts,
We have acquired single PLD, pcasl data on a large number of elderly adults (healthy and with Alzheimer’s). The data is in accordance with the white paper and the following parameters were used.
12 interleaved pairs of control-tagged images (total of 24)
Voxel size = 1.9 x 1.9 x 4 mm
TR = 4.6 s
Suppression mode = Gray-white-strong
Bolus duration = 1.5 s
Inversion time = 3.5 s
PLD = 2 s
Separate M0 scan, TR = 4s
T1 blood = 1.65 s
Labeling efficiency = 0.85
The intensity ranges of the control-tagged pairs, M0 and the subtracted (perfusion) images in one of the controls are 0 - 2222, 0 - 1549, 0 - 73, respectively. Leaving cgain to the default value, generates perfusion_calib files with unexpectedly high values (range = 0 – 1819). As such, I have set this option to 10 in oxford_asl command. The output, mean partial volume corrected gray matter perfusion is less than 50 ml/100g/min for all subjects. There are also some controls whose white matter perfusion is slightly higher than GM. My questions are:
What is the average range of total CBF (pvc) in GM for healthy controls?
Is it normal to have slightly higher CBF for WM in some subjects?
Is a gain factor of 10 an optimal value for the analyses? Any help would be greatly appreciated.
Kind regards,
Khazar
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