# Diagnostic performance of non-contrast quiescent-interval slice-selective (QISS) magnetic resonance angiography for evaluation of the renal arterial vasculature compared to computed tomography angiography (CTA) as reference standard

## TL;DR

This study compares non-contrast QISS MRA with CTA for evaluating renal arteries and finds that QISS MRA has similar diagnostic quality and detects most anatomical variants.

## Contribution

The study evaluates QISS MRA's diagnostic performance for renal arteries against CTA, focusing on anatomical variant detection.

## Key findings

- QISS MRA showed excellent diagnostic accuracy in detecting 19 out of 20 anatomical variants in renal artery branching patterns.
- CTA had significantly higher signal-to-noise ratio than QISS MRA, but QISS MRA had higher contrast-to-noise ratio.
- Both QISS MRA and CTA provided similar vessel diameters and high diagnostic confidence.

## Abstract

To evaluate the diagnostic quality and detection of anatomical variants in branching patterns of the renal arteries for non-contrast quiescent-interval slice-selective (QISS) MR Angiography (MRA) compared to CT Angiography (CTA).

Patients who underwent a QISS MRA of the renal arteries as well as CTA as reference standard were included in this retrospective study. Signal-to-noise ratio (SNR), contrast-to-noise ratio (SNR), and vessel diameter were determined in the left and right renal arterial systems. Image quality and diagnostic confidence were assessed with a standardized five-point Likert scale. Sensitivity, specificity and accuracy for the detection of anatomical variants in branching patterns (accessory renal artery, aberrant renal artery and early branching) of the renal arterial system were determined compared to CTA as reference standard.

30 patients (59 renal arteries) were included in this retrospective study. CTA reached significantly higher median SNR compared to QISS MRA (10.96, inter-quartile range (IQR) 6.70–16.11 vs. 5.65, IQR 4.38–8.76, respectively, p < 0.001). Median CNR was significantly higher in QISS MRA (16.75, IQR 13.09–20.96) compared to CTA (13.22, IQR 7.49–18.57), p = 0.006. Diameters of the renal arteries were similar between QISS MRA and CTA (5.8 mm, IQR 4.90–6.60 versus 5.8 mm, IQR 4.75, 6.70, p = 0.893). Diagnostic confidence was rated excellent for both, though significantly higher for CTA (5, IQR 5–5,) compared to QISS MRA (5, IQR 4–5), p = 0.003). 19 of 20 variants in branching pattern could be detected successfully by QISS.

QISS MRA offers similar diagnostic confidence and image quality to CTA as reference standard. Further, QISS MRA demonstrates excellent diagnostic accuracy in detecting anatomical variants of branching patterns of the renal arterial vasculature.