sup 11^C-Choline PET for Evaluation of Renal Tubular Function

Purpose: The aim of this study is to evaluate renal cortical choline activity on 11C-Choline PET/CT as a potential noninvasive biomarker for renal tubular function. METHOD AND MATERIALS. An IRB approved retrospective chart review was performed of 1602 consecutive male patients that had 11C-Choline PET/CT according to standard protocol for prostate cancer between 1/3/2017 and 10/30/2017. Standard protocol includes imaging from mid thighs to orbits beginning 5 minutes after injection of the radiotracer. All scans were reconstructed with standard 3D OSEM. Patients with renal function data in their medical record within 6 months of the PET/CT testing that included serum creatinine and eGFR (Modification of Diet in Renal Disease equation) and a urinalysis with predicted 24 hour protein were screened. Those with serum creatinine of 0.8-1.3 mg/dL, eGFR >60 mL/min/1.73m2, and a predicted 24-hour protein 1.3 mg/dL, eGFR ≤45 mL/min/1.73m2, and a predicted 24-hour protein >1000 mg/24hr were defined as an "abnormal renal function" group. Standard uptake values (SUV) were determined from volumetric regions of interest (5-10 mL in volume) in the renal cortex of each kidney. Data was collected and analyzed using GE Advantage Workstations, GE Picture Archiving Communication System (PACS), and MIM Version 6.6.7 DICOM Viewing and Storage software. Statistical analyses were completed using commercial software (JMP) and a student’s t-test for continuous variables and the chi-square test for categorical variables. RESULTS. In this pilot study, 7 men with abnormal renal function were compared to 20 age and sex matched men with normal renal function (average age 75.1±7.8 vs 72.3±6.2 yrs). Abnormal renal function patients had a SUVmean in the right and left renal cortex of 9.6±2.6 and 9.9±1.8, respectively. In the normal renal function group SUVmean was 15.7±5.0 and 15.0±4.2 in the right and left renal cortex, respectively. Thus, renal cortical uptake of 11C-Choline was 39% (p