MULTIPARAMETRIC MAGNETIC RESONANCE IMAGING IN EVALUATION OF BENIGN AND MALIGNANT BREAST MASSES WITH PATHOLOGICAL CORRELATION

Abstract

The MRI Breast Imaging-Reporting and Data System (BI-RADS) lexicon recommends that a breast MRI protocol contain T2-weighted and dynamic contrast-enhanced (DCE) MRI sequences. The addition of diffusion-weighted imaging (DWI) and apparent diffusion coefficient values significantly improves diagnostic accuracy. This study aims to study the descriptors from DCE-MRI, restricted diffusion on DWI, ADC values and choline peak on spectroscopy in breast cancer diagnosis. Objectives: 1. To assess morphology of breast mass using multiparametric MR mammography. 2. To correlate findings on MR mammography with pathological findings. Material and methods: This study was a prospective observational study which involved subjects with breast lump with inconclusive mammography or sonomammography findings. Baseline data was collected from the patients along with pertinent clinical history and relevant lab investigations. MR Mammography was performed on 1.5 Tesla, 18 channel, MR Scanner (Siemens® Magnetom Avanto®) using dedicated double breast coil. The following sequences were performed: T1 and T2 axial images, T1 sagittal, T2 coronal, DWI at 50, 400 and 800 s/mm2 b values with corresponding ADC sequences, Dynamic contrast enhancement study, kinetic curves and Spectroscopy. Chi-square was used as test of significance for qualitative data and independent t test was used as test of significance for quantitative data. p value < 0.05 was considered as statistically significant. XV Results: 41 subjects were included with a total of 54 breast masses in them. The mean age of the study population was 47.1 ± 14.7 years. From the MRI final diagnosis, majority (53.70%) were diagnosed as malignant lesions and 46.30% as benign. Out of 20 lesions diagnosed as benign on histopathology, only 5% had ADC value <1.3 and majority 95% had ADC value >1.3. All 20 lesions were circumscribed, ovoid or round in shape showing no restricted diffusion on DWI, with corresponding ADC value of >1.3×10−3mm2/s, homogenous post-contrast enhancement or with dark internal septations, type I kinetic enhancement curve and they showed no choline peak on spectroscopy. Out of 34 malignant lesions diagnosed on histopathology, majority (85.29%) displayed restricted diffusion on DWI and had an ADC value of <1.3×10−3mm2/s, most of them had spiculated margins, type 2/ 3 kinetic curve with choline peak on spectroscopy. Rest 14.71% had ADC value >1.3×10−3mm2/s, showing no restricted diffusion and were circumscribed, they were diagnosed to be mucinous carcinoma on histopathology. The difference in the proportion of ADC value between histopathological status was statistically significant (P value <0.001). Conclusion: Multiparametric MR mammography which included DCE-MRM, DWI, ADC values and spectroscopy correlated well with the histopathological diagnosis of benign and malignant breast masses.