Comparison of CASL Perfusion Signal with & without Velocity Dependent Labeling RF Power Modulation

S. L. Talagala¹, W-M. Luh², H. Merkle³

Velocity dependent labeling RF power modulation (VDLM) has been proposed as a possible method to achieve a high labeling efficiency throughout the cardiac cycle with minimum power deposition. Here, we investigate if real-time application of VDLM could be employed to increase the CASL signal when using a neck labeling coil. Current data indicate that the perfusion signal is dependent on the particular VDLM employed. When using the same average power, 3.5/1.5W VDLM was found to yield slightly higher perfusion signal compared to constant labeling. Further studies are needed to optimize VDLM in terms of perfusion signal. However, since VDLM can be used to reduce power deposition from the labeling pulse, it should prove useful for CASL perfusion MRI at higher magnetic field strengths.