ORIGINAL RESEARCH n VASCULAR AND INTERVENTIONAL RADIOLOGY Radiology: Volume 283: Number 1—April 2017 n radiology.rsna.org 293 1 From the Departments of Radiology (B.L., M.O., M.F., J.L., M.K., J.B., F.C., A.L., T.J.W.) and Biostatistics (J.P.), Florida Hospital, 601 E Rollins St, Orlando, FL 32803. Received April 19, 2016; revision requested June 28; revision received July 19; accepted August 8; final version accepted August 28. Address correspondence to T.J.W. (e-mail: thomasjward@gmail.com). q RSNA, 2016 Purpose: To review a single-center experience with the cortical tangential approach during computed tomography (CT)- guided native medical renal biopsy and to evaluate its ef- ficacy and safety compared with those of a non–cortical tangential approach. Materials and Methods: This retrospective study received institutional review board approval, with a waiver of the HIPAA requirement for informed consent. The number of cores, glomeruli, and complications were reviewed in 431 CT-guided medi- cal renal biopsies performed between July 2007 and Sep- tember 2015. A biopsy followed a cortical tangential ap- proach if the needle path was parallel to the renal cortical surface, at a depth closer to the renal capsule than the renal pelvic fat. A sample was considered adequate if the biopsy yielded at least 10 glomeruli at light microscopy, one glomerulus at immunofluorescence microscopy, and one glomerulus at electron microscopy. The x 2 test, the t test, the Mann-Whitney test, and logistic regression mod- eling of sample adequacy were performed. Results: One hundred fifty-six (36%) of 431 biopsies were per- formed with the cortical tangential approach. More cores were obtained for the cortical tangential group (2.6 vs 2.4, P = .001); biopsy needle gauge was not significantly differ- ent (P = .076). More adequate samples were obtained in the cortical tangential group (66.7% vs 49.8%, P = .001), with more glomeruli (23 vs 16, P = .014). Results were sig- nificant after controlling for needle gauge and number of cores (P = .008). The cortical tangential group had fewer complications (1.9% vs 7.3%, P = .018). Conclusion: The cortical tangential approach, when applied to CT- guided native medical renal biopsies, results in higher rates of sample adequacy and lower rates of postproce- dural complications. q RSNA, 2016 Bo Liu, MD Matthew O’Dell, MD Miguel Flores, MD Joseph Limback, MD Melissa Kendall, BS Julie Pepe, PhD Jeremy R. Burt, MD Francisco Contreras, MD Andrew R. Lewis, MD Thomas J. Ward, MD CT-guided Native Medical Renal Biopsy: Cortical Tangential versus Non-Tangential Approaches—A Comparison of Efficacy and Safety 1 This copy is for personal use only. To order printed copies, contact reprints@rsna.org