Regional perfusion imaging using pTILT

Purpose To demonstrate the feasibility that the pseudo‐continuous transfer insensitive labeling technique (pTILT) sequence can be modified to achieve regional perfusion imaging by either vessel‐encoded or vessel‐selective pTILT, similar to the regional perfusion imaging sequences using pseudo‐continuous arterial spin labeling (pCASL). Materials and Methods Static phantom experiments were carried out to investigate the selectivity and efficiency of region‐specific labeling by pTILT. The ability of the modified pTILT sequences to separate perfusion territories was also examined at two levels of the arterial tree on four healthy subjects: (i) the left and right internal carotid arteries (ICAs) and (ii) individual vascular territories of arteries above the circle of Willis (anterior cerebral artery [ACA], left and right middle cerebral arteries [MCAs]). Results In the phantom study, compared with non–region‐specific pTILT, a labeling efficiency of 0.92 and 0.88 was measured at the target vessels using vessel‐encoded and vessel‐selective pTILT, respectively. In human studies, the perfusion territories of ACA, left and right MCA branches with estimated CBF of 74.5 ± 26.1, 65.9 ± 7.2, and 72.3 ± 14.5 mL/100 g/min, respectively, as well as more general left/right end territories (76.8 ± 12.7 and 72.8 ± 7.2 mL/100 g/min), were clearly delineated by the modified pTILT sequences for regional perfusion imaging. Conclusion Two regional perfusion imaging modules (vessel‐encoded and vessel‐selective) used in pCASL can also be adapted into the pTILT sequence, and our results confirmed that the region‐specific pTILT sequence is capable of regional perfusion imaging to separate perfusion territories of major cerebral arteries. J. Magn. Reson. Imaging 2014;40:192–199 . © 2013 Wiley Periodicals, Inc .