Osmanuddin Ahmed MD, Presenter: Nothing to Disclose

Yonglin Pu MD, PhD, Abstract Co-Author: Nothing to Disclose

Maryellen L. Giger PhD, Abstract Co-Author: Stockholder, Hologic, Inc Shareholder, Quantitative Insights, Inc Royalties, Hologic, Inc Royalties, General Electric Company Royalties, MEDIAN Technologies Royalties, Riverain Medical Royalties, Mitsubishi Corporation Royalties, Toshiba Corporation Researcher, Koninklijke Philips Electronics NV Researcher, U-Systems, Inc

Alexandre Rosen MD, Abstract Co-Author: Nothing to Disclose

Shelby James Bennett MD, Abstract Co-Author: Nothing to Disclose

Hui Li PhD, Abstract Co-Author: Nothing to Disclose

John M. Collins MD, Abstract Co-Author: Nothing to Disclose

Bill C. Penney PhD, Abstract Co-Author: Nothing to Disclose

Mohan Gundeti, Abstract Co-Author: Nothing to Disclose

Current evaluation of patients with suspected urinary tract obstruction is retrospective, and requires loss of progressive renal function for diagnosis. Furthermore, prospective studies such as diuretic renal scintigraphy (DRS) using half-time (T ½) of tracer clearance have shown low positive predictive value. The objective of this study is to assess the utility of renal pelvic appearance time (PAT) to diagnose ureteropelvic junction (UPJ) obstruction that would benefit from surgical intervention.

An IRB-approved retrospective review was performed on 55 patients with clinically-suspected UPJ obstruction treated with pyeloplasty. Each patient had undergone a pre and post surgical DRS. The pre-surgical split kidney function (SKF), T ½ tracer clearance, and PAT were calculated on each patient. The ability of the PAT difference in seconds between the affected and contra-lateral kidneys in predicting improvement in post-surgical renal function was determined using the gold standard of split kidney function improvement > 5%. Area under the Receiver Operating Characteristic (ROC) curve (AUC) was used to assess the performance in distinguishing between patients with improved renal function and those without post surgery. The AUC of the PAT difference was compared with the T1/2 and SKF of the affected kidney.

Of the 55 patients who underwent pyeloplasty, 10 patients demonstrated a SKF improvement greater than 5% on the affected surgical side and 8 patients demonstrated a SKF decrease greater than 5%. AUC values for predicting improvement of renal function greater than 5% in the PAT difference between the affected and contra-lateral kidneys as well as the SKF and T ½ tracer clearance of the affected kidney were found to be 0.73 (SE=0.07), 0.68 (SE=0.09), and 0.63 (SE=0.14) respectively. AUC values for these same variables in predicting decline of SKF greater than 5% was found to be 0.74 (SE=0.11), 0.55 (SE=0.11), and 0.77 (SE=0.13) respectively.

This study shows the potential of PAT in patients with clinically suspected UPJ obstruction by predicting which patients would show improvement or decline in SKF following surgical pyeloplasty.

PAT may help clinicians determine which patients with suspected UPJ obstruction will benefit from pyeloplasty, and could potentially decrease unnecessary surgeries as well as time to treatment.

Ahmed, O, Pu, Y, Giger, M, Rosen, A, Bennett, S, Li, H, Collins, J, Penney, B, Gundeti, M, Improving Patient Selection for Pyeloplasty in Suspected UPJ Obstruction by Using Renal Pelvic Appearance Time on Renal Scintigraphy..  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12033541.html