Accuracy of MR imaging for revealing residual breast cancer in patients who have undergone neoadjuvant chemotherapy

OBJECTIVE. Our study investigated the usefulness of contrast-enhanced MR imaging for accurately measuring the size of residual tumor after patients have undergone neoadjuvant (preoperative) chemotherapy. The imaging analysis method was optimized for identifying residual disease in the treated breast. Tumor sizes measured on the MR images and at the clinical examination were compared with the size of residual disease measured at pathology after surgery.SUBJECTS AND METHODS. Before undergoing surgery, 52 patients were imaged before and after receiving ncoadjuvant chemotherapy. For each patient, specific malignancy criteria were applied to MR images before chemotherapy to identify the location of tumor, and residual disease was then identified as any remaining enhancement in the same area on the MR images after chemotherapy. Residual tumor size was measured using both the MR technique and the clinical examination findings, and the degree of measurement error for each method was assessed in comparison with the pathologic findings.RESULTS. The correlation with pathology was an r value of 0.89 for MR measurements compared with an r value of 0.60 for clinical measurements. In addition, MR imaging revealed all cases of residual disease, whereas clinical assessment resulted in five false-negative interpretations in the 52 treated lesions.CONCLUSION. The high correlation between measurements of residual disease obtained on MR images and those obtained at pathology validates the sensitivity of MR imaging of the breast after chemotherapy.

目的：我们的研究探讨了对比增强磁共振成像在准确测量患者接受新辅助（术前）化疗后残余肿瘤大小方面的有效性。对成像分析方法进行了优化，以识别治疗后的乳腺中残余的病变。将磁共振图像上和临床检查所测量的肿瘤大小与手术后病理所测量的残余病变大小进行了比较。 对象与方法：52名患者在手术前接受新辅助化疗前后均进行了成像。对于每位患者，在化疗前对磁共振图像应用特定的恶性肿瘤标准以确定肿瘤位置，然后将化疗后磁共振图像上同一区域的任何剩余强化视为残余病变。使用磁共振技术和临床检查结果测量残余肿瘤大小，并与病理结果比较评估每种方法的测量误差程度。 结果：磁共振测量与病理的相关性r值为0.89，而临床测量的r值为0.60。此外，磁共振成像显示出所有残余病变病例，而临床评估在52个治疗病变中有5例假阴性结果。 结论：磁共振图像上获得的残余病变测量值与病理获得的测量值之间的高度相关性验证了化疗后乳腺磁共振成像的敏感性。