High-resolution Lower Extremity Arterial MR Angiography with Parallel Acquisition and Automatic Table-moving Techniques

Objective To evaluate the diagnostic performance of high resolution lower extremity arterial MR angiography with parallel acquisition technique.Materials and Methods 80 patients were performed moving table high resolution 3D contrast enhanced MR angiography(3D CE MRA) of the lower extremity arteries. Three 3D CE MRA stations were acquired successively through automatic table moving. For analysis, the imaged arterial system was divided into 23 segments. Overall image quality of each arterial segment was scored. Early venous contamination in each scan station was scored too. The presence of arterial disease was evaluated and classified into the following: vessel irregularity with stenosis 10%; mild stenosis 50%; significant stenosis ≥50%; occlusion; and aneurysm formation. 3D CE MRA findings were also compared to other imaging modalities in 7 patients.Results 3D CE MRA of the lower extremity arteries was successfully performed in all patients. Our study identified all 1840 arterial segments in all subjects (100%) with mean visibility score of 3.78. Venous contamination was rated as none or minimal in all three stations and never interfered with arterial diagnosis with mean score of 0.25. The results showed lesions in 1458 arterial segments including 608 segments with irregularity; 498 segments with mild stenosis; 312 segments with significant stenosis; 38 segments with occlusion and 2 segments with aorta aneurysm formation. In 19 of 69 patients with PAOD, 3D CE MRA showed additional vascular narrowing involving the renal artery. It could also show the patency of the bypass graft. In cases with other imaging techniques available, the demonstration of vascular pathology all agreed by 3D CE MRA.Conclusion High resolution lower extremity arterial MR angiography with parallel acquisition technique has extended scan coverage, reduce imaging time, improve spatial resolution, and depict the lower extremity arteries clearly, it is very valuable for a comprehensive evaluation of lower extremity arterial diseases.