CORRELATION OF ULTRASOUND AND MAMMOGRAPHY TO HISTOPATHOLOGY IN BI-RADS IV AND V BREAST LESIONS, TAKING TISSUE DIAGNOSIS AS GOLD STANDARD

Abstract

Background:BI-RADS categories IV and V indicate breast lesions that present with a real possibility of malignancy and should be sampled with biopsy. Breast density, which is the norm in younger women from the South Asian community, significantly affects the sensitivity of mammography, and ultrasound plays some role in younger women from the South Asian community. This study aims to determine if either modality is a good predictor of the final diagnosis in this particular high-suspicion group. Objective:To assess the diagnostic accuracy of ultrasound and mammography in the diagnosis of breast BI-RADS categories IV and V lesions as a tissue diagnosis is the gold standard. Methods:This cross sectional study was carried out in the department of Radiology, Chaudhary Muhammad Akram Teaching and Research Hospital (CMATRH) Raiwind Road Lahore for a period of six months after approval of synopsis by College of Physicians and Surgeons Pakistan (CPSP). A non-probability consecutive sampling was used to sample women aged 35-55 years with a palpable breast lump, and lesions classified as BI RADS IV or V on ultrasound and/or mammography, after obtaining informed consent, for Tru-cut biopsy. Histopathology was used as the gold standard. Data were stratified by age, BMI, size, and duration and analyzed using chi-square test post stratification (p ≤ 0.05 considered significant) and a 2×2 contingency table was used to calculate sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy. Results:Histopathology was performed on 260 BI-RADS IV/V lesions, and 40.8% (106) of these were malignant. The ultrasound was 89.6% sensitive and 85.7% specific against histopathology, whereas the mammography was 58.3% sensitive and 77.9% specific; combining the two increased the sensitivity to 94.3% and specificity to 93.8% against histopathology. The malignancy rate increased from 14.5% in BI-RADS IV-A to 93.3% in BI-RADS V; invasive ductal carcinoma was the most common malignant diagnosis (45.3%), and fibroadenoma the most common benign diagnosis (23.6%). Conclusion:In this population, ultrasound was more sensitive than mammography for BI-RADS IV/V lesions, with an increase in sensitivity as the combination of both modalities was used, reflecting the limitations of mammography in younger women, due to density. Imaging can be any of the categories listed above but tissue diagnosis is still essential.