Analysis of breast cancer extension using new imaging technology, 3-D MRI

[引言]现在，随着保乳治疗被接受为治疗选择之一，癌症扩展的定义变得更加重要。本研究的目的是阐明磁共振成像（MRI）的能力，在定义乳腺癌的扩展，在与病理发现所创建的标本的亚连续切片。[材料与方法] 34例乳腺癌患者术前均行MRI检查，采用最大密度投影（MIP）法对肿瘤的范围进行三维评估。每个3-D MIP与通过亚序列映射获得的癌的相应病理分布进行比较。[结果和讨论]获得了三种成像模式，1)局限型（n=20），节段型（n=11）和随机广泛型（n=3）。局限型18例，TDLU检出癌灶，2例癌灶向乳头内扩散达4cm。节段性癌多沿着导管-小叶系统从TDLU至大导管分布。在MRI中清楚染色的肿瘤在组织学上显示为DCIS，其形成实性肿块。3例被归类为具有线性结构的随机广泛型，并且在组织学上被定义为具有弥漫性间质浸润的导管内扩散的癌，常规钼靶X线摄影和超声在14例被归类为节段性或随机广泛型的患者中的6例中低估了癌的扩展，这表明MRI更适合于在手术前估计癌的分布。10%（2/20）的局限型乳腺癌MRI表现为阴性，MRI在乳腺癌保乳手术中的应用有待进一步研究。

[Introduction]Now, definition of carcinoma extension becomes more important, as breast conserving therapy is accepted as one of the treatment options. This study was initiated to clarify the ability of magnetic resonance imaging (MRI) in defining the extension of breast carcinoma, in comparison with the pathologic finding created by subserial sectioning of the specimens.[Materials and Methods]Prior to surgery the MRI was performed to 34 patients with breast cancer, then extension of tumors were 3 dimensionally assessed in maximum intensity projection (MIP). Each 3-D MIP was compared to the respective pathologic distribution of carcinoma obtained by subserial mapping.[Results and Discussion]Three imaging patterns were obtained, e.g., 1) localized (n=20), 2) segmental (n=11), and 3) random extensive (n=3) types. Among the specimens classified in localized type, 18 were defined in the TDLU,and intraductal spread of carcinoma to the nipple as long as 4 cm of extension, was observed in 2 specimens. In most of the specimens with segmental type carcinomas distributed along the duct-lobular system from the TDLU to the large duct. Clearly stained tumors in the MRI were histologically revealed to be DCIS which forms solid mass. Three were categorized as random extensive type with linear architecture, and were histologically defined to be carcinomas with diffuse stromal invasion as intraductal spread.Conventional mammography and ultrasonography underestimated carcinoma extension in 6 of the 14 patients who were categorized as segmental, or random extensive type by the MRI,suggesting that the MRI is more appropriate to estimate carcinoma distribution prior to surgery. Ten percent (2/20) of patients with localized type, however, were not visualized in the MRI.Further investigation is required to develop the diagnostic technology in clinical utilization of MRI for breast conserving surgery.