Assessment of Suspected Breast Cancer by MRI: A Prospective Clinical Trial Using a Combined Kinetic and Morphologic Analysis

Abstract

OBJECTIVE. The objective of our study was to assess the incremental value of contrast-enhanced MRI in the diagnosis and treatment planning using both a three–time point kinetic and morphologic analysis in addition to mammography and sonography in patients thought to have early-stage breast cancer. SUBJECTS AND METHODS. Contrast-enhanced bilateral breast MRI was performed prospectively on 65 patients with highly suspicious imaging findings (BI-RADS category 4 or 5). All enrolled patients were believed to be candidates for breast conservation on the basis of clinical examination, mammography, and sonography. The primary index lesion's characteristics, size, and extent were assessed. Also, additional lesions detected by MRI that could represent potential malignancies in both the ipsilateral and contralateral breast were evaluated. Morphologic assessment and kinetic analysis were performed on each lesion using dedicated postprocessing and display software. The patients were reevaluated as to whether they were still candidates for breast-conservation therapy after the MRI examination and subsequent biopsies. RESULTS. There were 46 patients (71%) whose primary breast lesion (detected by mammography, sonography, or both) was found to be malignant (39 invasive breast cancers, five intraductal cancers, and two lymphomas). For the primary index lesions, the sensitivity for MRI was 100% (44/44) for predicting a breast malignancy and the specificity was 73.7% (14/19) for predicting benign lesions. MRI detected an additional 37 lesions, of which 23 were cancerous, beyond those suspected on mammography or sonography. One or more additional ipsilateral breast cancers were detected in 32% (14/44) of breast cancer patients and contralateral breast cancers in 9% (4/44) of the breast cancer patients. MRI also resulted in an incremental recommendation of mastectomy in 18% (8/44) of the pathologically confirmed breast cancer patients. MRI resulted in additional biopsy of only 14 benign lesions, six of which were shown to be atypical ductal hyperplasia. CONCLUSION. When added to the standard evaluation of clinical examination, mammography, and sonography in patients thought to have early-stage breast cancer, contrast-enhanced MRI using both a kinetic and morphologic analysis will often result in changes in recommended patient management and better treatment planning and will result in no significant increase in biopsies of benign lesions. In addition, there is a significant detection rate of occult contralateral breast cancers.