One-stop preoperative assessment of renal vessels for living donors with 3.0 T non-contrast-enhanced magnetic resonance angiography: compared with computerized tomography angiography and surgical results

Abstract

Objective: The study was to investigate the feasibility and accuracy of assessment for living renal donors before transplantation by using 3.0 T non-contrast-enhanced magnetic resonance angiography (NCE-MRA).

Methods: 30 renal donors were investigated and underwent computed tomography angiography (CTA) and 3.0 T NCE-MRA before nephrectomy. Two radiologists independently assessed arterial and venous anatomy and potential kidney lesions. The image quality score, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diameters and lengths of renal arteries and veins were compared between CTA and NCE-MRA. Imaging findings were compared with the surgical results served as reference standard. Agreement was assessed using κ test. The Wilcoxon test and paired sample t test were used for statistically significant differences.

Results: The results of image quality score for renal arteries and veins were highly consistent between the two radiologists in NCE-MRA (p < 0.001). There was no significant difference in the scores of renal arterial and venous branches between NCE-MRA and CTA (p > 0.05). The SNR and CNR of renal vessels were higher than CTA (p < 0.001). There were no statistically significant differences in the length of renal vessels measured by the two methods (p > 0.05), and the diameter was smaller than that of CTA (p < 0.05). The detection of normal renal arteries and early branches by both examination techniques was consistent with intraoperative findings. Both methods showed good consistency between the anatomical variation of renal vein and the intraoperative diagnosis (p < 0.001).

Conclusion: 3.0 T NCE-MRA can be used for evaluation of main renal arteries and veins with high accuracy for anatomy and variation classification, and can be used for pre-operative vascular evaluation of living donor kidney transplantation.

Advances in knowledge: 3.0 T NCE-MRA can be used for evaluation of main renal arteries and veins with high accuracy for anatomy and variation classification, and can be used for pre-operative vascular evaluation of living donor kidney transplantation.

Figure 1.

NCE-MRA was used to evaluate the quality standard of renal angiography, taking arteries as an example. 1 point, undiagnosable (a); 2 points, medium (b); 3 points, good (c); 4 points, excellent (d). NCE-MRA, non-contrast-enhanced magnetic resonance angiography

Figure 2.

(a) Comparison of SNR_RA, CNR_RA-RP and CNR_RA-ST in renal artery of two methods. ***: p < 0.001; (b) Comparison of SNR_RV, CNR_RV-RP and CNR_RV-ST in renal veins of the two methods. ***: p < 0.001. CNR, contrast-to-noise ratio; SNR, signal-to-noise ratio

Figure 3.

Post-processing images of renal artery anatomy and variation. SSFP MRA (a) and CTA (b) showed normal renal vein anatomy. SSFP MRA (c) and CTA (d) could display right renal accessory artery (arrow). SSFP MRA (e) and CTA (f) showed early branches of left renal artery (arrow). CTA, computed tomography angiography; MRA, magnetic resonance angiography; SSFP, steady-state free precession.

Figure 4.

Post-processing images of renal vein anatomy and variation. PC MRA (a) and CTA (b) showed normal renal vein anatomy. Both PC MRA (c) and CTA (d) can display right kidney accessory renal vein (arrow); Both PC MRA (e) and CTA (f) showed late right renal vein anastomosis (arrow). MPR images of PC MRA (g) and CTA (h) showed posterior abdominal aortic left renal vein (arrow). CTA, computed tomography angiography; MRA, magnetic resonance angiography; PC, phase contrast.