3.0T磁共振成像在接受过经尿道膀胱肿瘤切除术膀胱癌中诊断肌层浸润的应用

目的: 评价3.0T 磁共振成像(magnetic resonance imaging, MRI)在接受过经尿道膀胱肿瘤切除术(transurethral resection of bladder tumor, TURBT)膀胱癌中诊断肌层浸润情况的应用价值。方法: 选择2012年9月至2019年4月在郑州大学附属肿瘤医院收治的接受过TURBT两周后行3.0T MRI的膀胱癌患者病例资料进行回顾性分析,共收集到病例55例。由具有10年以上阅片经验的放射科医师协商诊断,通过MRI的T2加权像(T2 weighted imaging, T2WI)和/或扩散加权成像(diffusion-weighted imaging, DWI)判定膀胱癌是否存在肌层浸润,并与全膀胱切除术后的病理诊断相比较,评估3.0T MRI诊断膀胱癌肌层浸润情况(≥T2期)的敏感度、特异度和准确度。结果: 纳入的 55例患者,平均年龄60.76岁(42~82岁),男性48例,女性7例。MRI检查前均接受过TURBT(其中郑州大学附属肿瘤医院 16例,外院39例);所有患者MRI检查和TURBT间隔时间均大于2周,所有患者均在MRI检查后1个月内行根治性全膀胱切除术,且MRI检查后至根治性全膀胱切除期间未行放疗或化疗。术后病理诊断证实未见肿瘤残留2例;非肌层浸润性膀胱癌16例,其中13例分期为T1,3例分期为Ta期;肌层浸润性膀胱癌37例,其中19例分期为T2, 14例分期为T3, 4例分期为T4。放射诊断使用T2WI序列、DWI序列、T2WI+DWI序列诊断肌层浸润性膀胱癌的敏感度分别为94.59%、83.78%、91.89%,特异度分别为66.67%、77.78%、72.22%,准确度分别为85.45%、81.82%、85.45%。结论: T2WI序列拥有良好的软组织分辨率,有利于可疑病灶的发现及定位;DWI序列可以帮助医师区分膀胱癌和瘢痕纤维化;3.0T MRI T2WI+DWI序列在接受过TURBT的膀胱癌中对诊断肌层浸润情况拥有较高的准确度,具有一定的应用价值。

Bladder cancer local staging about muscle invasion: 3.0T MRI performance following transurethral resection

Objective: To evaluate the performance of 3.0T magnetic resonance imaging examination (MRI) for the local detecting of muscle invasive bladder cancer following transurethral resection of bladder tumor (TURBT). Methods: Retrospective study identified 55 patients with pathology-proven bladder cancer who underwent transurethral resection of bladder tumor followed by 3.0T magnetic resonance imaging between September 2012 and April 2019 in our hospital. Two radiologists reviewed pelvic magnetic resonance imaging together and judged muscle invasive bladder cancer. Sensitivity, specificity and accuracy were calculated for the presence of muscle invasion by T2 weighted imaging (T2WI) only, diffusion-weighted imaging (DWI) only and T2WI+DWI compared with the findings at radical cystectomy as the reference standard. Results: Of the 55 patients with pathological results from radical cystectomy, 3.64% (2/55) had no residual disease; 29.09% (16/55) were non-muscle invasive bladder cancer on pathology, including 13 cases in T1 and 3 cases in Ta; 34.55% (19/55) were in stage T2 depending on pathology, 25.45% (14/55) in T3, and 7.27% (4/55) in T4. The average age was 60.76 years, ranging from 42 to 82 years. There were 48 males and 7 females in our study. Before pelvic MRI examination, all the patients received transurethral resection of bladder tumor, including 16 cases taking the operation in our hospital and 39 cases in other hospitals. The interval between the pelvic MRI examination and transurethral resection of bladder tumor was more than 2 weeks in all the patients. They all underwent radical cystectomy within 1 month after the pelvic MRI examination, and no patient underwent radiotherapy or chemotherapy in our study during the interval between the MRI examination and radical cystectomy. T2WI only, DWI only, and T2WI+DWI of 3.0T magnetic resonance imaging for readers were with sensitivity: 94.59%, 83.78%, 91.89%; with specificity: 66.67%, 77.78%, 72.22% and with accuracy: 85.45%, 81.82%, 85.45%, respectively. Conclusion: 3.0T MRI may have a role in diagnosing muscle invasive bladder cancer following TURBT. T2WI has the advantage of detecting the location of bladder tumor, and DWI has the advantage of differentiating between the benign and malignant lesion. 3.0T MRI T2WI+DWI has a good utility in the detection of muscle invasive bladder cancer following TURBT with satisfied accuracy.