Depiction Of Transplant Renal Vascular Anatomy And Complications:Non-contrast Enhanced MR Angiography Using Spatial Labeling With Multiple Inversion Pulses

Part1Depiction of Transplant Renal Vascular Anatomy:Non-contrast Enhanced MR angiography Using Spatial Labeling with Multiple Inversion PulsesPurpose:To prospectively evaluate the performance of a non-contrast enhanced MR angiography using spatial labeling with multiple inversion pulses, to depict transplant renal vascular anatomy in comparison to color Doppler ultrasonography (CDUS).Materials and Methods:This study was approved by the institutional review board (IRB), and all patients gave written informed consent before examination.75patients with renal transplant were examined with non-contrast enhanced MRA using SLEEK and CDUS. The ability to present transplant renal vascular anatomy with SLEEK was evaluated in consensus by two experienced radiologists, and to compare the results with operative notes. The ability of SLEEK detected accessory artery was analyzed using the Chi-square test.Results:A total of75patients underwent renal transplantation were examined with CDUS and SLEEK. There were3patients with two renal transplant and9patients with nine accessory renal arteries. Image quality of all patients was acceptable. The image quality was categorized as excellent in85%(66of78), good in10%(8of78) and moderate in5%(4of78) of the patients. Significantly more of accessory renal arteries were detected with SLEEK than with CDUS (P<0.05).Conclusions:Non-contrast enhanced MRA using SLEEK was preliminarily proven to be a reliable diagnostic method for depicting the anatomy of transplant renal vascular. It’s likely to serve as a choice for imaging evaluation of the patients with renal transplantation, in particular with renal insufficiency. Part2Depiction of Transplant Renal Vascular Complications: Non-contrast Enhanced MR angiography Using Spatial Labeling with Multiple Inversion PulsesPurpose:To prospectively evaluate the performance of a non-contrast enhanced MR angiography using spatial labeling with multiple inversion pulses, to depict transplant renal vascular complications in comparison to color Doppler ultrasonography (CDUS), digital subtraction angiography (DSA) and intraoperative findings.Materials and Methods:This study was approved by the institutional review board (IRB), and all patients gave written informed consent before examination.23patients with renal transplant were examined with non-contrast enhanced MRA using SLEEK and CDUS. The ability to present transplant renal vascular complications with SLEEK was evaluated in consensus by two experienced radiologists, and to compare the results with CDUS, DSA and intraoperative findings.Results:23patients were diagnosed with transplant renal vascular complications, including14with arterial stenosis (3with arterial occlusion),3with arterial kinking,2with arteriovenous fistulas,2with venous stenosis, lwith pseudoaneurysms and1with fibromuscular dysplasia. The ability of SLEEK found vascular complications is superior to CDUS, but there were no statistically significant differences between them (P>0.05).Conclusions:Non-contrast enhanced MRA using SLEEK was preliminarily proven to be a reliable diagnostic method for depicting the complications of transplant renal vascular. It’s likely to serve as a choice for imaging evaluation of the patients with renal transplantation, in particular with renal insufficiency. Part3Depiction of Transplant Renal Arterial Stenosis:Non-contrast Enhanced MR angiography Using Spatial Labeling with Multiple Inversion Pulses versus DSAPurpose:To prospectively evaluate the performance of a non-contrast enhanced MR angiography using spatial labeling with multiple inversion pulses, to depict transplant renal arterial stenosis in comparison to digital subtraction angiography (DSA).Materials and Methods:This study was approved by the institutional review board (IRB), and all patients gave written informed consent before examination.11patients with renal transplant arterial stenosis were examined with non-contrast enhanced MRA using SLEEK and DSA. The ability to present transplant renal arterial stenosis with SLEEK was evaluated in consensus by two experienced radiologists, and to compare the results with DSA.Results:11patients were diagnosed with transplant renal arterial stenosis. With SLEEK, only one grade1stenosis on DSA was evaluated as grades3stenosis. The correlation between SLEEK and DSA was found in presenting the degree of TRAS (r=0.96; p<0.05). With SLEEK, a slight overestimation of the degree of stenosis was observed (median,57.5%; range,35-76%; mean,56.3%±13.6%), compared with the degree of stenosis estimated with DSA (median,56.5%; range,30-75%; mean,53.1%±13.8%), but there was no significant difference between them (Wilcoxon signed-rank test, P=0.57). The Bland-Altman plot showed very low bias in assessment of the degree of stenosis by using SLEEK (mean bias,3.2%±7.3%). The sensitivity of SLEEK for identifying a significant stenosis (>50%narrowing) was100%, and the specificity was75%. The positive predictive value was87.5%, the negative predictive value was100%, and the accuracy was90.9%.Conclusions:Non-contrast enhanced MRA using SLEEK was preliminarily proven to be a reliable diagnostic method for depicting the transplant renal arterial stenosis. It’s likely to serve as a choice for imaging evaluation of the patients with renal transplantation, in particular with renal insufficiency. Part4Parameter Optimization for Blood Suppression Inversion Time (BSP TI):Non-Contrast Enhanced MR Angiography using Spatial Labeling with Multiple Inversion Pulses of Transplant Renal ArteryPurpose:To evaluate non-contrast enhanced MR angiography using spatial labeling with multiple inversion pulses visualization of the transplant renal artery, and explore the optimization of BSP TI Materials and Methods:20volunteers with renal transplantation were examined under different BSP TI (500,800,1100,1400ms), and the vessel-to-renal parenchyma contrast ratio of the transplant renal arteries were measured.Results:Non-contrast-enhanced MRA images of transplant renal arteries were obtained successfully in all20volunteers. The signal intensity of transplant renal arterial branches gradually increased when BSP TI increased from500ms to1400ms, and the highest vessel-to-renal parenchyma contrast ratio occurred when TI was800ms and1100ms.Conclusion:Non-contrast enhanced MR angiography of the transplant renal artery can be successfully achieved at1.5T high field MRI. Fixed BSP TI of800ms and1100ms are preferable.