Diagnostic Value of Breast Magnetic Resonance Imaging in Cases Requiring Further Examination after Breast Cancer Screening

Abstract

We evaluated the diagnostic value of breast magnetic resonance imaging (MRI) in cases requiring further examination after breast cancer screening by mammography (MMG) and ultrasonography (US). Three hundred and sixty-four women visited our outpatient clinic for follow-up breast examination. Seventy-seven women underwent MRI, and consequently 18 were diagnosed as having breast cancer. Among 47 cases of category 3 based on MMG assessment, 8 were diagnosed as breast cancer, and MRI detected all of them. No lesion suspected to be malignant was detected in 37 of 39 cases in which the final diagnosis was normal or benign. Among 11 MMG category 4 cases, 4 were diagnosed as breast cancer, and MRI detected all of them. No lesion suspected to be malignant was detected in 5 of 7 cases for which the final diagnosis was normal or benign, but 2 cases of mastopathy were diagnosed as indeterminate by MRI. Four of 17 cases that required further examination after US screening were diagnosed as malignant. MRI detected these lesions; moreover, MRI alone detected an additional malignant lesion in one case. Among 13 cases finally diagnosed as normal or benign, MRI detected no features suggestive of malignancy. Our findings suggest that the negative predictive value of breast MRI for detection of breast cancer is higher than that of MMG and US. Breast MRI is considered appropriate and is recommended for secondary screening in cases requiring further examination after breast cancer screening.