Test–retest multiple‐PLD/TI pCASL and PASL data sets were previously acquired.15 , 23 The PASL study was approved by the Hospital da Luz Ethics Committee, and all subjects gave written informed consent in accordance with the Declaration of Helsinki. The pCASL study was carried out under an agreed technical development protocol approved by the Oxford University Clinical Trials and Research Governance office, in accordance with International Electrotechnical Commission and United Kingdom Health Protection Agency guidelines.
In the PASL study, 9 healthy volunteers (22.9 ± 5.6 y, 4 males) were studied on a 3T Siemens Verio whole‐body MRI system (Erlangen, Germany) using a 12‐channel‐receive head RF coil, on 2 sessions separated by ~1 wk.15 In the pCASL study, 8 healthy volunteers (28.3 ± 2.5 y, 6 males) were studied on a 3T Siemens Verio whole‐body MRI system (Erlangen) using a 32‐channel receive head RF coil, on 3 occasions separated by 1 wk and 1 mo.23 A reference image with no labeling or background suppression, TR = 6s, and all other parameters identical to the pCASL scan, was collected for calibration. In both data sets, T1‐weighted structural images were acquired from each subject for tissue segmentation and registration purposes. Acquisition details for both data sets are summarized in Table 2 .
In the PASL study, 9 healthy volunteers (22.9 ± 5.6 y, 4 males) were studied on a 3T Siemens Verio whole‐body MRI system (Erlangen, Germany) using a 12‐channel‐receive head RF coil, on 2 sessions separated by ~1 wk.