Repeatability of Quantitative FDG-PET/CT and Contrast-Enhanced CT in Recurrent Ovarian Carcinoma: Test–Retest Measurements for Tumor FDG Uptake, Diameter, and Volume

Abstract

Purpose: Repeatability of baseline FDG-PET/CT measurements has not been tested in ovarian cancer. This dual-center, prospective study assessed variation in tumor 2[18F]fluoro-2-deoxy-D-glucose (FDG) uptake, tumor diameter, and tumor volume from sequential FDG-PET/CT and contrast-enhanced computed tomography (CECT) in patients with recurrent platinum-sensitive ovarian cancer.Experimental Design: Patients underwent two pretreatment baseline FDG-PET/CT (n ¼ 21) and CECT (n ¼ 20) at two clinical sites with different PET/CT instruments. Patients were included if they had at least one target lesion in the abdomen with a standardized uptake value (SUV) maximum (SUVmax) of !2.5 and a long axis diameter of !15 mm. Two independent reading methods were used to evaluate repeatability of tumor diameter and SUV uptake: on site and at an imaging clinical research organization (CRO). Tumor volume reads were only performed by CRO. In each reading set, target lesions were independently measured on sequential imaging.Results: Median time between FDG-PET/CT was two days (range 1-7). For site reads, concordance correlation coefficients (CCC) for SUVmean, SUVmax, and tumor diameter were 0.95, 0.94, and 0.99, respectively. Repeatability coefficients were 16.3%, 17.3%, and 8.8% for SUVmean, SUVmax, and tumor diameter, respectively. Similar results were observed for CRO reads. Tumor volume CCC was 0.99 with a repeatability coefficient of 28.1%.Conclusions: There was excellent test-retest repeatability for FDG-PET/CT quantitative measurements across two sites and two independent reading methods. Cutoff values for determining change in SUVmean, SUVmax, and tumor volume establish limits to determine metabolic and/or volumetric response to treatment in platinum-sensitive relapsed ovarian cancer. Clin Cancer Res; 20(10); 2751-60. Ó2014 AACR.

Repeatability of SUV in Oncologic 18F-FDG PET

“…Table 1 shows the articles that were identified and included in this review. Sixteen papers (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), published between 1995 and 2016, met the inclusion criteria. All were reports on original research, although there was some overlap in the source data: Nakamoto et al (22) (28) performed a metaanalysis pooling data from 5 previously published cohorts.…”

“…Each of these studies involved a careful test-retest protocol with two repeated imaging sessions using the same protocol and scanner system for each patient. Four of the publications (25,(31)(32)(33) included data acquired at multiple centers, although, to be clear, individual patients were always scanned on the same system. The remaining reports were on single-center studies.…”

“…Careful adherence to maintaining consistent uptake periods was a feature of most studies. For example, Rockall et al (32) reported that, for a given patient, the difference in the uptake periods between scan 1 and scan 2 averaged 1.9 min. Such careful control of uptake periods was important for optimizing repeatability but may not be typical of clinical conditions.…”

“…In general, there have been 3 different VOI approaches, with their corresponding SUVs being SUV max (22,23,(25)(26)(27)(29)(30)(31)(32)(33)(34)(35), SUV mean (21,(23)(24)(25)(26)(27)(29)(30)(31)34,35), and SUV peak (20,22,23,25,27,(32)(33)(34)(35). As is usual, SUV max was derived from the single tumor voxel with the highest uptake.…”

“…The most common approach was to analyze a single tumor per patient (20)(21)(22)24,25,29,31,33,34). Another approach allowed for the inclusion of a variable number of tumors per patient, analyzing all tumors collectively (21,23,26,27,30,35) or averaging the tumor SUVs for an individual patient and assessing the repeatability of the average SUV (25,32,33,35). Inclusion criteria in terms of minimum tumor size or SUV were not always specified.…”