Harkirat S, Anand Ss, Jacob Mj
Department of Nuclear Medicine and PET/CT Facility, Army Hospital (R and R), New Delhi, India.
Indian J Radiol Imaging. 2010 Feb;20(1):13-9. doi: 10.4103/0971-3026.59746.
The results of (18)F-fluorodeoxyglucose (FDG)-PET imaging carried out with the current standard techniques for assessment of urinary tract cancers have been reported to be less than satisfactory because of the urinary excretion of the tracer.
To investigate the role of dual-phase FDG-PET/CT in the restaging of invasive cancers of the urinary bladder, with delayed imaging after forced diuresis and oral hydration as the scanning protocol.
FDG-PET has been considered to be of limited value for the detection of urinary tract cancers because of interference by the FDG excreted in urine. We investigated the efficacy of delayed FDG-PET/CT in the restaging of invasive bladder cancer, with imaging performed after intravenous (IV) administration of a potent diuretic and oral hydration.
Twenty-nine patients with invasive cancer of the urinary bladder were included in this study. Patients were divided into two groups: Group I (22 patients) included cases with invasive bladder cancer who had not undergone cystectomy and group II (seven patients) included cases with invasive bladder cancer who had undergone cystectomy and urinary diversion procedure. All patients underwent FDG-PET/CT scan from the skull base to the mid-thighs 60 min after IV injection of 370 mega-Becquerel (MBq) of FDG. Additional delayed images were acquired 60-90 min after IV furosemide and oral hydration. PET/CT data were analyzed as PET and CT images studied separately as well as fused PET/CT images and the findings were recorded. The imaging findings were confirmed by cystoscopy, biopsy or follow-up PET/CT.
The technique was successful in achieving adequate washout of urinary FDG and overcame the problems posed by the excess FDG in the urinary tract. Hypermetabolic lesions could be easily detected by PET and precisely localized to the bladder wall, perivesical region and pelvic lymph nodes. PET/CT delayed images were able to demonstrate 16 intravesical lesions (in 13 patients), with excellent clarity. Lymph node metastases were detected in a total of six patients. Of these, in two patients, FDG-avid lymph nodes were evident only in the delayed images. The information provided by the postdiuretic delayed images changed the PET/CT interpretation in 14 patients of invasive bladder cancer: Recurrent bladder lesions were identified in 12 patients, pelvic lymph node metastasis (only) in one patient and bladder lesion as well as lymph node metastasis in one patient. Distant metastases were detected by PET/CT in two cases. CT scan was false-negative for early recurrence in the bladder wall for seven of 16 lesions. CT also showed two false-positive lesions. There were no false-positives with PET.
Detection of recurrent disease in cases of invasive bladder cancer can be significantly improved by using FDG-PET/CT, with delayed imaging following forced diuresis and oral hydration. Composite PET/CT is superior to CT alone for the restaging of invasive bladder cancers.
据报道，采用当前评估尿路癌的标准技术进行的（18）F-氟脱氧葡萄糖（FDG）-PET成像结果并不理想，原因是示踪剂会经尿液排出。
以强制利尿和口服补液后延迟成像作为扫描方案，研究双期FDG-PET/CT在膀胱浸润性癌再分期中的作用。
由于尿液中排出的FDG产生干扰，FDG-PET被认为对尿路癌的检测价值有限。我们研究了延迟FDG-PET/CT在膀胱浸润性癌再分期中的疗效，成像在静脉注射强效利尿剂和口服补液后进行。
本研究纳入了29例膀胱浸润性癌患者。患者分为两组：第一组（22例患者）包括未接受膀胱切除术的膀胱浸润性癌病例，第二组（7例患者）包括接受膀胱切除术和尿流改道术的膀胱浸润性癌病例。所有患者在静脉注射370兆贝可勒尔（MBq）FDG后60分钟，接受从头颅底部至大腿中部的FDG-PET/CT扫描。在静脉注射速尿和口服补液后60 - 90分钟获取额外的延迟图像。PET/CT数据分别作为PET图像、CT图像以及融合后的PET/CT图像进行分析，并记录结果。成像结果通过膀胱镜检查、活检或随访PET/CT得以证实。
该技术成功实现了尿液中FDG的充分清除，克服了尿路中过量FDG带来的问题。PET能够轻松检测到高代谢病变，并精确将其定位到膀胱壁、膀胱周围区域和盆腔淋巴结。PET/CT延迟图像能够清晰显示16例膀胱内病变（13例患者）。总共6例患者检测到淋巴结转移。其中，2例患者仅在延迟图像中出现FDG摄取阳性的淋巴结。利尿后延迟图像提供的信息改变了14例膀胱浸润性癌患者的PET/CT解读：12例患者发现复发性膀胱病变，1例患者发现盆腔淋巴结转移（仅），1例患者发现膀胱病变以及淋巴结转移。PET/CT检测到2例远处转移。对于16个病变中的7个，CT扫描对膀胱壁早期复发呈假阴性。CT还显示了2例假阳性病变。PET未出现假阳性。
通过使用FDG-PET/CT并结合强制利尿和口服补液后的延迟成像，可显著提高膀胱浸润性癌病例中复发性疾病的检测率。对于膀胱浸润性癌的再分期，复合PET/CT优于单独的CT。
