Hemodialysis access imaging: comparison of flow-interrupted contrast-enhanced MR angiography and digital subtraction angiography.

Abstract

To compare flow-interrupted contrast material-enhanced magnetic resonance (MR) angiography with conventional digital subtraction angiography (DSA) for hemodialysis access imaging. Twenty-two accesses (14 arteriovenous grafts [AVGs], eight arteriovenous fistulas [AVFs]) in 18 consecutive patients were imaged with flow-interrupted contrast-enhanced MR angiography and subsequent conventional DSA. MR image quality was assessed as excellent, good, or nondiagnostic. Anastomotic diameters in AVGs and postanastomotic diameters in AVFs were measured in consideration of an adjacent normal segment. Reductions in the diameter of the lumen and interobserver differences were analyzed with method comparison as described by Bland and Altman and expressed as the mean difference with its 95% confidence limits (CLs) (mean +/- 2 SDs). Image quality obtained with flow-interrupted contrast-enhanced MR angiography was considered excellent in 73% (16 of 22) and good in 23% (5 of 22). Method comparison analysis between MR angiography and DSA indicated a mean difference of 3.2% (95% CLs: -26.7%, 33.1%) for observer 1 and 4.1% (95% CLs: -23.8%, 32.1%) for observer 2. Interobserver analysis at MR angiography indicated a mean difference of 3.2% (95% CLs: -28.8%, 35.2%), and that at DSA indicated a mean difference of 3.6% (95% CLs: -9.4%, 16.7%). Image quality and anatomic depiction with flow-interrupted contrast-enhanced MR angiography and with DSA were comparable.