Acceleration of Magnetic Resonance Cholangiopancreatography Using Compressed Sensing at 1.5 and 3 T: A Clinical Feasibility Study.

Abstract

Magnetic resonance cholangiopancreatography (MRCP) is an established technique in routine magnetic resonance examination. By applying the compressed sensing (CS) acceleration technique to conventional MRCP sequences, scan time can be markedly reduced. With promising results at 3 T, there is a necessity to evaluate the performance at 1.5 T due to wide scanner availabilities. Aim of this study is to test the feasibility of accelerated 3-dimensional (3D) MRCP with extended sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) using CS in navigator triggering and in a single breath-hold in a clinical setting at 1.5 T and 3 T and compare it with a conventional navigator-triggered 3D SPACE-MRCP. Phantom measurements were performed to adapt sequence parameters. Conventional 3D SPACE-MRCP in navigator triggering (STD_MRCP) as well as CS-accelerated 3D SPACE-MRCP acquired in navigator triggering and in a single breath-hold (CS_MRCP and CS_BH_MRCP) was performed in 66 patients undergoing clinically induced MRI of the pancreatobiliary system at 1.5 T and 3 T. Image quality evaluation was performed by 2 independent radiologists. Dedicated statistics were performed (P < 0.05 considered significant). In patient imaging, CS_MRCP was superior to STD_MRCP and CS_BH_MRCP in aspects of overall image quality at 1.5 T (P = 0.01; P < 0.001) and 3 T (P = 0.002; P = 0.013). Overall image quality in CS_BH_MRCP was inferior compared with STD_MRCP and CS_MRCP at 1.5 T. At 3 T, overall image quality in CS_BH_MRCP was superior to STD_MRCP (P = 0.001). Scan time was reduced by 25% to 46% covering 5% of k-space (CS_MRCP at 1.5 and 3 T) and 97% covering 3.6% of k-space (CS_BH_MRCP at 1.5 and 3 T). Compressed sensing-accelerated MRCP is feasible in clinical routine at 1.5 and 3 T offering major reduction of acquisition time. When applying a single breath-hold CS imaging, field strengths of 3 T are recommended.