MR背景抑制扩散加权成像在乳腺癌的应用

目的 探讨MR扩散加权成像(DWI)结合短时间反转恢复回波成像(STIR-EPI)背景抑制(BS)技术在乳腺癌成像的技术参数及其可行性.方法 回顾性分析26例乳腺癌的MR DWIBS测得各组织的表观扩散系数(ADC),利用三维最大强度投影(3D-MIP)重组及黑白反转技术,观察病变显示效果.观察乳腺痛DWI及DWIBS两种方法的显示率.对乳腺各组织的ADC值进行随机区组设计的方差分析,在乳腺癌与良性病变ADC值的比较中,采用t检验.对两种成像方法乳腺癌的显示率进行配对资料X2检验.结果 在扩散敏感因子(b)=800 mm2/s的图像中,乳腺癌多表现为高信号,其ADC值分别为:肿瘤实质(0.93±0.25)×10-3 mm2/s、瘤内坏死灶(2.06±0.17)×10-3 mm2/s、正常腺体(1.92±0.23)×10-3 mm2/s、转移性淋巴结(1.10 ± 0.14)×10-3mm2/s,各种组织间两两比较,差异具有统计学意义(P值均＜0.01).DWIBS经MIP重组及黑白反转技术,病变周围组织信号被抑制,得到类正电子发射体层成像(PET)图像.在乳腺癌中,DWIBS对肿瘤实质(92.3/)及转移性淋巴结(88.4/)的显示率要高于DWI序列(分别为57.6/和42.3/),差异有统计学意义(x2值分别为8.307、12.235,P均＜0.05).乳腺癌与良性病变ADC值分别为(1.092±0·17)×10-3和(2.154±0.53)×10-3mm2/s,差异有统计学意义(t=8.626,P＜0.05).结论 MRDWIBS在显示病灶方面有一定优势,应用DWI结合ADC值对乳腺癌的诊断具有临床应用前景.

MR diffusion weighted imaging with background signal suppression in breast cancer

Objective To explore the feasibility of echo planar imaging with short time inversion recovery(STIR-EPI)diffusion weighted imaging with background signal(DWIBS)suppression in breast cancer.Methods The diffusion weighted imaging(DWI)with background suppression(b=800 mm2/s)was performed in 26 patients with breast cancer.Apparent diffusion coefficient(ADC)of all lesions,vere measured and compared.3D maximum intensity projection(3D-MIP)and reverse black and white technique were used to show the lesions.DWI and DWIBS were performed and compared for the detection of breast cancer. Randomized blocks analysis of variance was used for the ADC values in different breast tissues.the ADC values in breast cancer and benign lesion were compared using t test.The paired chi square tes:was used for the detection rate of breast cancer in two different imaging methods.Results Most of the breast cancers were hyperintense on DWI(b:800 mm2/s).,rhe ADC value of caneer tissue was(0.93±0.25)×10-3mm2/s,tumor necrosis was(2.06±0.17)×10-3 mm2/s,normal breast tissue was (1.92±0.23)×10-3 mm2/s and metastatic lymph node was(1.10±0.14)× 10-3mm2/s and the differenees were statistically significant between two structures(P＜0.01).The signal of the tissue8 around the breast cancer was decreased on DWIBS with 3 D-MIP and reverse black and white technique and similar to positron emission tomography(PET).DWIBS sequence detected more breast cancers(92.3/)and metastatic lymph nodes(88.4/)than DWI sequence did(57.6/and 42.3/,respectively,X2:8.307,P＜0.05;X2=12.235,P＜0.05).The ADC values in breast cancer(1.09±0.17)×10-3mm2/s and benign lesion (2.15±0.53)×10-3 mm2/s had significant statistical differences(t=8.626,P＜0.05).conclusion Diffusion weighted MRI with background suppression can detect more lesions than DWI and can be potentially applied for the detection of the breast cancer eombining the ADC value.