Functional MRI evaluation of blood oxygen dependent (BOLD) in renal allograft dysfunction: a prospective study.

BACKGROUND: Blood oxygen level dependent-magnetic resonance imaging (BOLD-MRI) is a non-invasive functional imaging technique that can be used to assess renal allograft dysfunction. PURPOSE: To evaluate the diagnostic performance of BOLD-MRI using a 3-T scanner in discriminating causes of renal allograft dysfunction in the post-transplant period. MATERIAL AND METHODS: This prospective study was conducted on 112 live donor-renal allograft recipients: 53 with normal graft function, as controls; 18 with biopsy-proven acute rejection (AR); and 41 with biopsy-proven acute tubular necrosis (ATN). Multiple fast-field echo sequences were performed to obtain T2*-weighted images. Cortical R2* (CR2*) level, medullary R2* (MR2*) level, and medullary over cortical R2* ratio (MCR) were measured in all participants. RESULTS: The mean MR2* level was significantly lower in the AR group (20.8 ± 2.8/s) compared to the normal group (24 ± 2.4/s, P <0.001) and ATN group (27.4 ± 1.7/s, P <0.001). The MCR was higher in ATN group (1.47 ± 0.18) compared to the AR group (1.18 ± 0.17) and normal functioning group (1.34 ± 0.2). Both MR2* (area under the curve [AUC] = 0.837, P <0.001) and MCR (AUC = 0.727, P = 0.003) can accurately discriminate ATN from AR, however CR2* (AUC = 0.590, P = 0.237) showed no significant difference between both groups. CONCLUSION: In early post-transplant renal dysfunction, BOLD-MRI is a valuable non-invasive diagnostic technique that can differentiate between AR and ATN by measuring changes in intra-renal tissue oxygenation.

Renal arterial embolization: Indications, angiographic findings, and outcomes in a series of 170 patients.

Background: The lack of overall experience and reporting on angiographic findings in previously published studies of renal arterial embolization (RAE) compelled us to report our overall experience on a series of patients. Materials and methods: A retrospective study was performed analyzing data of patients enrolled for RAE between 2010 and 2019. History, physical examination, and laboratory data were reviewed for all patients. Abdominal ultrasound was the initial imaging study, and all patients underwent subsequent computed tomography or magnetic resonance imaging. The outcome of RAE was determined based on radiographic and clinical findings. Results: Data from 202 patients were analyzed, with a mean age of 45 ± 15 years, and 71.3% of patients were male. Iatrogenic injury was the most common indication for RAE (54%), followed by renal tumors, trauma, and spontaneous, in 27.7%, 10.4%, and 8.4% of patients, respectively. Renal angiography revealing pseudoaneurysm alone or with other pathology in the lower pole of the kidney was the most common finding (40.6%), whereas no lesions were identified on angiography in 32 patients (15.8%), after which RAE was subsequently aborted. Renal arterial embolization was successful in 158 of 170 patients (92.9%) after 1 or more trials (maximum of 4). Microcoil alone or with other embolic materials was the most commonly used material for embolization (85%). Conclusions: Iatrogenic injury was the most common indication for RAE. Pseudoaneurysm alone or with other lesions was the most common lesion on renal angiography; however, angiography showed a negative result in 16% of patients, even those with symptoms. When lesions are present on angiography, the overall success of repeated trials of RAE reached 92.9%.

Predictors of renal angioembolization outcome: A retrospective analysis with 148 patients at a tertiary urology institute.

Objective: The aim of this study was to evaluate the predictor of unsuccessful outcome of renal angioembolization (RAE). Knowing those predictors may help in avoiding unnecessary RAE procedures and their associated side effects, while helping to prepare for an alternate procedure and improving patient's overall satisfaction. Methods: A retrospective analysis between January 2006 and December 2018 was performed, and the indications for RAE were classified into post-traumatic, iatrogenic, renal tumors, and spontaneous. Patients who underwent RAE prior to nephrectomy were eliminated. Computed tomography angiography was performed in patients with normal renal function and those who had no contrast allergy, otherwise magnetic resonance angiography was performed. For the purpose of statistical analysis, we stratified patients into two main categories based on the final outcome-successful or failed. Results: Of 180 patients, 32 with negative angiography were eliminated, leaving 148 patients; 136 (91%) had successful outcomes after one or more trials and 12 had unsuccessful outcomes. The mean age was 45±15 years, and 105 (71%) were male. Neither gender, side of the lesion, presence of hematuria, indication for RAE, nor the type of lesion affected the outcome. On the other hand, renal anatomy with presence of accessory artery was the only predictor to failed RAE (p=0.001). Failed RAE trial was a predictor for nephrectomy as a secondary procedure (p=0.03). Conclusion: No pre-procedural predictors could anticipate the RAE outcome, and different indications can be scheduled to RAE, which is equally effective. The presence of accessory renal artery on diagnostic angiography is the only factor that may predict the failure of the procedure.