饮水排尿再充盈延迟显像在膀胱病灶PET／CT检查中的价值

Value of delayed PET/CT on diluted and filled bladder for the detection of bladder cancer

目的探讨提高SUVmax显示阈值结合大量饮水排尿后充盈膀胱延迟显像在^18F—FDGPET／CT诊断膀胱病灶中的价值。方法回顾性分析2007年7月至2012年10月因可疑膀胱占位和膀胱肿瘤治疗后（保留膀胱）行^18F—FDGPET／CT显像的患者63例[男55例，女8例，平均年龄69．1岁]，常规显像后患者饮水1500～2000ml，觉憋尿时排尿，重复3次后再次充盈膀胱行盆腔延迟显像。对常规显像图进行2次阅片分析，第2次是对提高SUVmax显示阈值（从6—8至8～20）后的显像图再分析。所有患者经病理活组织检查或随访（〉6个月）确诊。观察常规显像与延迟显像尿液SUVmax及膀胱病灶^18F—FDG代谢的变化。采用配对样本t检验分析数据。结果常规显像和延迟显像尿液的SUVmax分别为15．11±11．11和4．73±2．00，差异有统计学意义（t=4．15，P〈0．01）。经病理及临床随访，63例患者中，发现膀胱病变18例（恶性15例，良性3例），均为PET／CT检出，3例PET／CT假阳性中，2例无^18F—FDG代谢增高（良性），1例为炎性反应。余45例PET／CT显像膀胱未见明显异常的患者经临床影像学随访6个月以上均未发现病变。16个病灶（16例患者）表现为^18F—FDG代谢增高，其中15例为膀胱癌原发或复发病灶，1例为炎性反应。16例PET显像高代谢病灶中，常规显像SUVmax显示阈值范围下分析，有18．8％（3／16）为阳性；提高SUVmax显示阈值范围后43．8％（7／16）为阳性。结论提高SUVmax显示阈值结合大量饮水排尿后再次充盈膀胱行延迟显像用于可疑膀胱肿瘤及膀胱肿瘤治疗后的^18F—FDGPET／CT显像，可有效提高膀胱病灶的检出率和诊断准确性。

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, ^18F-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, ^18F-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±1811.11 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.