Non-contrast-enhanced MR angiography for detecting arteriovenous fistula dysfunction in haemodialysis patients

Abstract

To assess the diagnostic value of non-contrast-enhanced magnetic resonance angiography (NCE-MRA), using time-of-flight and black-blood MRA, in the evaluation of arteriovenous fistulas in haemodialysis patients in comparison to multidetector computed tomography angiography (MDCTA). NCE-MRA and MDCTA were performed on the same day in 21 patients on maintenance haemodialysis with dysfunctional arteriovenous fistulas. The fistulas included three segments: arterial inflow, anastomosis, and venous outflow. Two experienced observers, who were blinded to the results of the NCE-MRA, recorded in consensus the significant stenoses (≥50%) seen on CTA. Two other experienced observers, unaware of the results of CTA, independently recorded significant stenoses (≥50%) in the NCE-MRA. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of NCE-MRA were calculated, with MDCTA as the standard reference. Sixty-three vascular segments in the 21 patients were clearly displayed. For the two observers of NCE-MRA, the accuracy was 98% and 95.4%; sensitivity 96.4% and 96.4%; specificity 97.1% and 94.3%; positive predictive value 96.4% and 93.1%; and, negative predictive value 97.1% and 97.1%. Inter-/intra-observer agreement for detecting stenosis was excellent for NCE-MRA, with a weighted kappa of 0.968 (95% confidence interval [CI], 0.874-1) and 0.936 (95% CI, 0.848-1). Non-contrast-enhanced MRA, using time-of-flight and black-blood MRA, is a reproducible and reliable imaging technique for detecting ≥50% stenosis in dysfunctional haemodialysis arteriovenous fistulas.