MR背景抑制弥散成像评价乳腺癌根治术后局部复发的价值

Value of MR Diffusion Weighted Imaging with Background Body Signal Suppression in Evaluation of Local Tumor Recurrence after Radical Mastectomy

目的:探讨MR背景抑制弥散成像(DWI-BS)评价乳腺癌根治术后及放疗后局部复发的价值。方法:对临床怀疑复发的17例乳腺癌根治术并放射治疗后病例行MR背景抑制弥散成像检查,其中有复发者11例,无复发者6例,所有病例均由手术病理或追踪复查证实。测量并比较两组胸壁病灶最小表观弥散系数(ADC)值,并计算诊断准确率、敏感度、特异度、阳性预测值、阴性预测值。结果:肿瘤复发组平均最小ADC值[(1.08±0.38)×10-3mm2/s]显著低于无复发组平均最小ADC值[(2.15±0.42)×10-3mm2/s],P<0.01),以1.40×10-3mm2/s为界值,诊断准确率为82%,敏感度82%,特异度83%,阳性预测值90%,阴性预测值71%。弥散加权反转最大密度投影能够直观显示复发病灶范围。结论:MR背景抑制弥散成像可能帮助鉴别乳腺癌根治术及放疗后是否复发。

Purpose： To investigate the value of MR diffusion weighted imaging with background body signal suppression （DWIBS） in differentiation of local tumor recurrence and post - treatment changes after mastectomy and radiation therapy. Methods： MR diffusion weighted imaging with background body signal suppression were performed on 17 patients who were clinically suspected of local recurrent breast cancer after radical mastectomy and radiation therapy. Eleven cases of recurrent tumor and 6 cases of non - recurrent were confirmed by biopsy or follow up examination. Mean minimal apparent diffusion coefficient （ADC） values of suspected lesions of the two groups were compared. Diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value were calculated. Results： The mean minimal ADC value of recurrent group[ （1.08± 0.38） × 10^-3mm^2/s] was less than that of non- recurrent group[ （2.15 ± 0.42） × 10^-3mm^2/s], the difference was significant statistically（P 〈 0.01）. When an ADC value of 1.40 × 10^-3mm^2/s was used as a threshold value for differentiation, the best results were obtained with an accuracy of 82 %, sensitivity of 82 %, specificity of 83 %, positive predictive value of 90%, and negative predictive value of 71%. The site and range of chest wall local recurrent tumors were well visualized with the 3D MIP DWI images. Conclusion： MR diffusion weighted imaging with back-ground body signal suppression（DWIBS） is useful in differentiation of local tumor recurrence and post - treatment changes after mastectomy and radiation therapy.