不同高b值小视野扩散加权成像对非肌层与肌层浸润性膀胱癌的鉴别价值

摘要

Objective To analyze the different signs between non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC), to explore the diagnostic value of reduced field-of-view (rFOV) diffusion weighted imaging (DWI) with different high b value at 3.0T magnetic resonance imaging (MRI) on NMIBC and MIBC. Methods Clinical and MRI data of 65 patients with bladder cancer (109 cancer focus, including 72 cases of NMIBC and 37 casesof MIBC) confirmed by surgery and pathology from October 2014 to July 2017 were collected from the Frist People's Hospital of Yibin. The patients were divided into NMIBC group and MIBC group. Different signs of rFOV DWI in preoperative conventional MRI with b value of 800 s/mm2, 1500 s/mm2, 2000 s/mm2 were analyzed. The apparent diffusion coefficient (ADC value) was compared between the two groups when b value is 1500 s/mm2. The ADC value of bladder tissue from 50 normal volunteers were compared with those of two groups. Results The DWI signs of"horseshoe sign", low signal below tumor, reduced tumor volume, decreased tumor signal and high signal of bladder wall below tumor showed significant difference between the NMIBC group and MIBC group (P<0.05). The signs of NMIBC were"horseshoe sign", low signal below tumor, reduced tumor volume and decreased tumor signal, with the positive rates of 88.89%, 83.33%, 59.72%, 61.11%, respectively. The signs of MIBC was high signal of bladder wall below tumor, whose positive rate was 86.49%. There were significant differences in ADC mean values between NMIBC, MIBC and normal bladder wall (P<0.05). Conclusion There are significant differences between NMIBC and MIBC in rFOV DWI imaging with different high b value, and ADC value is helpful to distinguish NMIBC and MIBC when the b value is 1500 s/mm2. Comparative observation of rFOV DWI images with different high b values has important value in distinguishing between NMIBC and MIBC.%目的 分析非肌层浸润性膀胱癌(NMIBC)和肌层浸润性膀胱癌(MIBC)的征象差异,探究磁共振(MRI)采用不同高b值小视野(rFOV)扩散加权成像(DWI)对两者的鉴别价值.方法 收集宜宾市第一人民医院2014年10月至2017年7月经手术病理证实的65例膀胱癌患者(109个癌灶,其中NMIBC 72个,MIBC 37个)的临床和MRI资料,并分为NMIBC组和MIBC组,分析其术前常规MRI中b值为800 s/mm2、1500 s/mm2,2000 s/mm2时rFOV DWI图像的不同征象,以及b值为1500 s/mm2时两组的表观扩散系数(ADC值)比较,另选50例正常志愿者膀胱壁与两者做ADC值比较.结果 两组间"马蹄征"、肿瘤下方低信号、肿瘤体积缩小、肿瘤信号减低、肿瘤下方膀胱壁高信号5项DWI征象比较差异均有统计学意义(P<0.05);NMIBC征象为"马蹄征"、肿瘤下方低信号、肿瘤体积缩小、肿瘤信号减低,其阳性率分别为88.89%、83.33%、59.72%%、61.11%;MIBC征象为肿瘤下方膀胱壁高信号,阳性率为86.49%;NMIBC、MIBC和正常膀胱壁的ADC平均值间比较差异均有统计学意义(P<0.05).结论 NMIBC和MIBC在rFOV不同高b值DWI成像时的征象存在明显差异,b值为1500 s/mm2时的ADC值有助于两者鉴别.不同高b值rFOV DWI图像对比观察在两者鉴别中具有重要价值.