Bilateral contrast-enhanced MR angiography of the hand: diagnostic image quality of accelerated MRI using echo sharing with interleaved stochastic trajectories (TWIST)

Objectives To evaluate the image quality of time-resolved contrast-enhanced MRA (tr-MRA) employing echo-sharing with stochastic trajectories for the bilateral examination of the hands. Methods In this institutional review-bord approved study, Tr-MRA was compared with multiphasic contrast-enhanced MRA (mp-MRA) featuring sub-systolic venous compression in 20 healthy volunteers at 3.0 T using the following settings: TR/TE: 2.8/1.2 ms, flip angle: 25°, acceleration factor: 4, effective voxel size: 0.9 × 0.8 × 0.9 cm, acquisition time 4.9 s per 3D volume. Results With tr-MRA the arterial first-pass contrast agent transit is clearly seen. On average the contrast agent arrived 34 s post-injection and reached the proper digital arteries after 44 s. The mean arterio-venous window was 13 s. Bilateral contrast enhancement was asynchronous in 56–62%. On a semiquantitative scale (0 = non-sufficient to 4 = excellent) tr-MRA (mp-MRA) yielded an average ranking of 2.8–3.6 (3.1–3.8) in the greater and intermediate sized segments and 1.3–2.0 (1.6–2.3) in the proper digital arteries. Conclusion Compared with established multiphasic ce-MRA, time-resolved MRA allows a four times faster acquisition. It reflects the natural haemodynamics of the hand arteries with no need for sub-systolic venous compression and may be beneficial in the detection of hand circulation disorders. Image quality is comparable to mp-MRA. In both techniques depiction of the proper digital arteries is limited.