乳腺黏液腺癌MRI表现特征及其与病理对照研究

目的 探讨乳腺黏液腺癌MR平扫、动态增强(DCE)及DWI表现特征及其与病理表现的相关性.方法 MR枪查采用1.5 T MR扫描仪及乳腺专用线圈,包括MR平扫、3D DCE-MRI以及b值分别为500和1000 s/mm2的DWI.对8例行乳腺MR检查并经手术病理证实的乳腺黏液腺癌,依据乳腺影像报告和数据系统(BI-RADS)MRI标准,回顾性分析病变形态学、T1WI及T2WI信号强度、肿块内部强化特征及动态增强曲线类型、DWI上ADC值表现,并与病理对照,乳腺黏液腺癌病理诊断依据2003年WHO乳腺肿瘤病理学标准.结果 8例乳腺黏液腺癌(5例单纯黏液腺癌,3例混合型黏液腺癌)的黏液含昔为60%～90%.8例在MRI上均表现为肿块,平扫T1WI呈低信号,T2WI呈高和明显高信号.动态增强后,1例表现为不均匀轻微强化,2例表现为内部欠均匀的渐进性强化,其余5例于动态增强早期时相均表现为边缘明显强化,肿块内部结构呈渐进性强化,强化方式呈由边缘强化向中心渗透趋势.于DWI上病变均表现为明显高信号,平均ADC值在b值500 s/mm2时为(2.41±0.28)×10-3mm2/s,b值1000 s/mm2时为(2.06±0.14)×10-3mm2/s,分别高于正常乳腺组织的(1.71±0.32)×10-3和(1.43±0.24)×10-3mm2/s.结论 乳腺黏液腺癌在MR平扫T2WI、DEC及DWI表现均不同于常见的浸润性导管癌,这些特征性表现反映了其特殊的病理类型,MR多种成像序列相结合可对乳腺黏液腺癌在术前作出正确诊断.

MRI features of mucinous carcinoma of the breast: correlation with histopathology

Objective To characterize the features of breast mucinous carcinoma on T2WI, dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion weighted imaging (DWI) and correlate the MR features with histopathology. Methods MR imaging in 8 women (aged 33--65 years old) with mncinous carcinoma of the breast verified histopathologically was performed on 1.5 T scanner with T1WI, FS T2 WI, 3D DCE-MRI using volume imaging for breast assessment(VIBRANT) sequence, DWI with b value of 500 and 1000 s/mm2 by single-shot EPI sequence. According to the lexicon of BI-RADS-MRI designed by ACR, the MR findings were retrospectively studied, including morphology, signal intensity on T1WI and FS T2WI, mass enhancement, the patterns of dynamic enhancement curve, and the mean ADC on DWI. The pathologic diagnosis was made according to the standard criteria by the World Health Organization Classification of Tumors. Results Five patients were pure mucinous carcinoma and 3 patients were the mixed. The amount of mucus ranged from 60% to 90%. All 8 tumors presented as a mass on MRI with low signal intensity on T1WI, high or strongly high signal intensity on FS T2WI and high signal on DWI. The tumor size ranged from 1.3 to 3. 2 cm in diameter. Five tumors showed rim enhancement in early phase and the central part was gradually enhanced in delayed phase. One tumor presented slightly heterogeneous enhancement. Two tumors showed progressively heterogeneous enhancement. The mean ADC values of tumor were (2.41±0.28) ×10-3 mm2/s with b value of 500 s/mm2 and (2.06 ±0. 14) × 10-3 mm2/s with b value of 1000 s/mm2, and higher than that of the normal breast tissue ( 1.71 ±0. 32) × 10-3 and ( 1.43 ± 0. 24) × 10-3 mm2/s]. Conclusions The MR features of breast mucinous carcinoma on T1WI, DCE-MRI, and DWI are different from that of invasive ductal carcinomas and may reflect its distinct histological type. The combination of these MR sequences may lead to a pre-operative diagnosis of this tumor.