Quantitative single breath-hold renal arterial spin labeling imaging at 7T.

PURPOSE: To evaluate the feasibility of quantitative single breath-hold renal arterial spin labeling (ASL) imaging at 7T.
METHODS: A single-shot fast spin echo FAIR (flow-sensitive alternating inversion recovery) method was used to perform two studies. First, a multi-delay perfusion study was performed to estimate the spin labeling temporal bolus width achievable with a local transceiver array coil at 7T. Second, with a conservatively defined bolus width, a quantitative perfusion study was performed using the single subtraction approach. To address issues of B1+ inhomogeneity/efficiency and excessive short-term specific absorption rates, various strategies were used, such as dynamic radiofrequency shimming and optimization.
RESULTS: A conservative temporal bolus width of 600 ms determined from the multi-delay study was applied for single-subtraction imaging to measure the renal blood flow in the cortex and medulla: 303 ± 31.8 and 91.3 ± 15.2 (mL/100 g/min), respectively. The estimated spatial and temporal signal-to-noise ratios of renal perfusion measurements were 3.8 ± 0.7 and 2.4 ± 0.6 for the cortex, and 2.2 ± 0.6 and 1.4 ± 0.2 for the medulla.
CONCLUSION: With proper management of field strength specific challenges, quantitative renal ASL imaging can be achieved at 7T within a single breath-hold. Magn Reson Med 79:815-825, 2018.