Peripheral magnetic resonance angiography (MRA) with continuous table movement at 3.0 T - Initial experience compared with step-by-step MRA

Purpose: To compare a standard step-by-step and a newly developed continuous table movement (CTM) technique for peripheral magnetic resonance angiography (MRA) at a 3.0-Tesla MR system equipped with a matrix coil system. Materials and Methods: We included 14 consecutive patients referred for peripheral MRA with clinical symptoms of peripheral arterial occlusive disease Fontaines stages II-IV. All of them underwent both step-by-step MRA and CTM-MRA in one session. Patients with impaired renal function (calculated glomerular filtration rate <30 mL/min) were not included. All examinations were performed on a 3.0-Tesla MR system. Maximal contrast agent volume was 31.5 mL (1.5 mL testbolus, 15 mL/MRA technique). For both techniques the same biphasic CA injection protocol was used, first 8 mL were injected at a flow rate of 1.5 mL/s directly followed by 7 mL at 0.8 mL/s again followed by 25 mL of saline also at 0.8 mL/s. Spatial resolution of the CTM-MRA datasets was technically limited to 1.2 mm(3), step-by-step MRA reached 1.4 x 1.1 x 1.2 mm(3) in the abdominal station, 0.9 x 0.9 x 0.9 mm(3) in the most distal calf station. First CTM-MRA datasets were read and findings thereafter correlated with the step-by-step MRA datasets. Examination time of both examinations were recorded and compared. Results: All datasets could be evaluated. The first 4 CTM-MRA cases were limited by incorrect timing in the most distal vessels obscuring distinct atherosclerotic changes of those vessels. Because of the absence of multiple localizers and subtraction masks examination time was considerably shorter when using the CTM-MRA technique. Relevant findings that were detected by the step-by-step MRA were also detected by CTM-MRA. Conclusion: MRA with CTM is an easy applicable technique for imaging peripheral vessels without the need for planning different steps and field of view positioning, thereby reducing examination time considerably. However, the slightly reduced spatial resolution compared with standard step-by-step MRA is a drawback especially in the most distal calf vessels.