Value of delayed PET/CT on diluted and filled bladder for the detection of bladder cancer / 中华核医学与分子影像杂志

ABSTRACT

Objective To evaluate the value of increased threshold of SUVmax and delayed imaging on diluted and filled bladder for improving the detection of bladder cancer with 18F-FDG PET/CT.Methods From July 2007 to October 2012,18 F-FDG PET/CT was performed on 63 suspected or treated (with bladder preserved) bladder cancer patients (55 males,8 females,average age 69.1 years).After routine imaging,all patients were given 1 500-2 000 ml of water orally three times and voided three times.Then they underwent delayed pelvic imaging at a full bladder status.The routine images were reanalyzed with increased SUVmax threshold (from 6-8 to 8-20).The final diagnosis was confirmed by pathology or follow-up (＞6 months).The differences of SUVmax in urine,18 F-FDG metabolism in lesions between routine and delayed imaging were compared.Paired t test was used to compare their differences.Results The SUVmax of urine on routine and delayed imaging was 15.11±11.11 and 4.73±2.00 respectively (t=4.15,P＜0.01).Among the 63 patients,there were 15 malignant and 3 benign cases confirmed by pathology,and 45 patients without obvious abnormality during follow-up.All 18 cases were detected by 18F-FDG PET/CT including the 3 benign false positive cases (2 were positive by CT though negative by PET,and 1 FDG-avid cystitis).All 15 true positive cases were confirmed as primary or recurrent bladder carcinoma and 1 false positive case as inflammation.The detection rates of early imaging with routine and increased display threshold of SUVmax were 18.8％(3/16) and 43.8％(7/16),respectively.Conclusion Increased SUVmax threshold for display and delayed imaging with diluted urine under full bladder status could effectively improve the detection rate of primary or recurrent bladder cancer with 18F-FDG PET/CT.