Feasibility Study Of For One-stop Assessment Of Living Renal Donors Before Transplantation With Non-contrast-enhanced MR

Objective To investigate the feasibility and accuracy of non-contrast enhanced magnetic resonance for one-stop assessment of living renal donors before transplantation,and to explore the consistency between non-contrast-enhanced MR and CTA and intraoperative evaluation results.Methods From May in 2018 to December in 2019,thirty donors undergoing parental kidney transplantation were prospectively collected and underwent abdominal CTA examination.All subjects were supine in the Philips Ingenia 3.0T MR scanner for routine MR,cross-sectional non-contrast-enhanced MRA（NCE-MRA）examination and coronary MRU examination.SSFP sequence was used for artery scan and PC sequence for vein scan.The image quality of original and reconstructed NCE-MRA images were scored by two radiologists independently.NCE-MRA and CTA were scored for the display of different graded branches of renal arteries,renal veins,and display of renal vein branches.The signal-to-noise ratio（SNR）of the renal vessels on NCE-MRA and CTA,the contrast-to-noise ratio(CNR_RA-RP,CNR_RV-RP)of renal artery（RA）and renal vein（RV）to renal parenchyma（RP）,and the contrast-to-noise ratio(CNR_RA-ST,CNR_RV-ST)of renal artery and renal veins and paravertebral muscles（ST）were measured on NCE-MRA and CTA.The diameters and lengths of renal arteries and veins in the NCE-MRA and CTA were measured.The sensitivity,specificity,accuracy,positive predictive value（PPV）and negative predictive value（NPV）of NCE-MRA and CTA to display renal artery variation and renal vein variation were calculated based on renal vessels.Kappa test was used to analyze the consistency of vascular scores between the two physicians.Wilcoxon test was used to compare the display scores of renal vascular branches and left renal vein branches.Wilcoxon test was used to compare the renal vessels SNR,CNR_RA-RP,CNR_RV-RP,CNR_RA-ST and CNR_RV-ST between the left and right renal vessels and NCE-MRA and CTA.The diameters and lengths of renal arteries and veins trunk on NCE-MRA and CTA images were compared by paired sample t test.Kappa test was used to test the consistency of NCE-MRA and CTA compared with the intraoperative diagnosis results.Results NCE-MRA showed acceptable image quality for both renal arteries and renal veins.The results of image quality score for renal artery and renal vein were highly consistent between the two physicians（P<0.001）.There was no significant difference in the scores of renal arterial and venous branches between NCE-MRA and CTA（P=0.157）.PC MRA showed the number of left renal vein branches was less than CTA（P<0.001）.There were no statistically significant differences in SNR,CNR_RA-RP,CNR_RV-RP,CNR_RA-ST and CNR_RV-ST in left and right renal arteries and renal veins（all P>0.05）.The SNR,CNR_RA-RP and CNR_RV-ST of renal artery measured by SSFP MRA were higher than that of CTA（P<0.001）.The SNR,CNR_RV-RP and CNR_RV-ST of PC MRA renal vein were all 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.The diagnosis of accessory renal artery by SSFP MRA was consistent with the intraoperative results（K=0.933,P<0.001）.PC MRA and CTA showed good consistency between the anatomical variation of renal vein and the intraoperative diagnosis（K>0.81,P<0.001）.A total of 3 renal cysts were detected in this study,and no abnormalities were found in the collection system and ureter of all subjects.Conclusion Non-contrast enhanced MR can safety,non-invasive,clear display of renal parenchyma,vascular system and collection system with no contrast agent and high accuracy,can be used for one-stop preoperative assessment of living kidney transplant donors.