PMC

Perfusion images registered to standard space with corresponding s.d. maps reflecting regional perfusion variability within and between imaging sessions. CASL, continuous arterial spin labeling; p-CASL, pseudo-continuous arterial spin labeling; s.d., standard deviation; TI PASL, inversion time pulsed arterial spin labeling.

Arterial spin labeling obtained on admission. Arterial spin labeling signals increased in the giant aneurysm (arrowheads) and decreased in the left hemisphere.

A‐C, Contour map of the simulated weighted mean labeling efficiency (LE) (weighted average of each /B₀ condition) for RF duration = 300 us, 500 us, and 800 us, respectively. The highest weighted‐mean LE in the (RF duration, , and ) 3D parameter space was achieved with (300 us, 0.3 mT/m, and 11). The red asterisk mark in (A) indicates “labeling 3,” which was determined as the final optimal 7T pseudo‐continuous arterial spin labeling (pCASL) later. D‐F, Simulated LE versus and B₀ for labeling 0, labeling 1, and labeling 3, respectively. Compared with labeling 0 (D), labeling 1 (E) and labeling 3 (F) showed increased robustness to B₀ offset. Compared with labeling 1, labeling 3 showed increased optimal amplitude and lower LE when amplitude was low (< 70%) due to increased

(A) Schematic pulse sequence diagrams of the different arterial spin labeling methods, where L_A is the acceleration-selective labeling module, L_V is the velocity-selective labeling module, and C is the control module and I is imaging. (B) Schematic depiction of the radio frequency (RF) pulses and gradients (G) in the labeling modules of acceleration-selective arterial spin labeling (AccASL), velocity-selective ASL (VS-ASL), and in the control (C) condition. pCASL, pseudo-continuous ASL.