MR低信号分隔征鉴别乳腺良恶性肿瘤的价值

Value of the hypointensive internal septation on MR for the differentiation between benign and malignant breast lesions

目的评价MR低信号分隔征在乳腺良、恶性肿瘤鉴别诊断中的价值。方法回顾性分析了经手术病理及临床随访证实的12例20个乳腺癌和14例25个纤维腺瘤的MR表现特点，分析低信号分隔征的鉴别诊断价值。结果乳腺癌和纤维腺瘤在MR抑脂T2 WI信号可为等、高信号，低信号，混杂信号，3种信号在乳腺癌分别为5、11、4个，在纤维腺瘤分别为11、10、4个，两者差异无统计学意义（X^2=1.764，P=0.414）。病灶形状可分为不规则形、类圆形和分叶状，3种形状在乳腺癌和纤维腺瘤分别为12、7、1个和1、7、17个，差异有统计学意义（X^2=23.262，P=0.000）。纤维腺瘤特征性表现分叶状、抑脂T2 WI及增强后低信号分隔征，诊断纤维腺瘤的敏感度分别为68％（17／25）、52％（13／25）、72％（18／25），特异度分别为95％（19／20）、90％（18／20）、95％（19／20）。结论低信号分隔征是诊断乳腺纤维腺瘤较特异的征象之一。

Objective To investigate the diagnostic value of internal septation for differentiating benign from malignant breast lesions. Methods A total of 26 patients were included in the study, in which 12 patients had 20 lesions of breast carcinoma and 14 patients had 25 lesions of fibroadenoma diagnosed either pathologically or clinically. The differential diagnoistic value of the hypointensive internal septation was analyzed. Results The signal intensity of fibroadenomas and malignant lesions on T2-weighted fat-suppressed images could be classified as iso- to hyper- intensity, hypointensity and mixed intensity. According to the signal intensity classification, there were 5, 11 and 4 cases in patients with breast carcinoma respectively, while 11, 10, 4 cases in patients with fibroadenoma respectively. There was no statistical difference in the distribution between the two patient groups （X^2 = 1.764,P =0. 414 ）. The shape of fibroadenomas and malignant lesions could be classified as irregular,roundish or lobulated. According to the morphological classification, there were 12, 7 and 1 case in patients with breast carcinoma respectively, while 1, 7, 17 cases in patients with fibroadenoma respectively. There was statistical difference in the distribution between the two patient groups （ X^2 = 23.262,P =0.000）. The typical features of fibroadenomas were as follows： lobulated shape, hypointensive internal septations on T2-weighted or postcontrast images. The diagnostic sensitivity of the three imaging features for fibroadenoma was 68% （ 17/25 ） , 52% （ 13/25 ）, and 72% （ 18/25 ） respectively; and the diagnostic specificity was 95% （ 19/20）, 90% （ 18/20）, 95% （19/20） respectively. Conclusion The internal septation is a rather specific sign for diagnosis of fibroadenomas.