The impact on diagnostic accuracy of an abbreviated screening breast magnetic resonance imaging (MRI) protocol in detecting lobular carcinoma

Abstract

Purpose: This study evaluated and compared the diagnostic accuracy of an abbreviated protocol against a full protocol for breast MRI in detecting lobular carcinoma Objectives: To compare the diagnostic accuracy and cancer yield of an abbreviated protocol to a full protocol using breast imaging reporting and data system classification (BI-RADS); determine diagnostic accuracy through ROC curves; calculate performance indicators for both protocols. Methodology: 35 cases undertaken during the period January 2019 and December 2021; 20- biopsy confirmed lobular carcinoma; 15- normal (negative follow up imaging). Two radiologists independently reviewed the abbreviated protocol. The data collected was compared with data collected from initial radiological MRI reports based on the full protocol. Lesions with BI-RADS category 1 or 2 were considered negative while BI-RADS of 3,4 or 5 considered positive. Results were analysed using ROC analysis. Results: The area under the curve obtained from each ROC curve was 1- full protocol, 0.920 and 0.922 for radiologist A and B for the abbreviated protocol respectively. The p-value (<0.05) for all the corresponding protocols indicated that each protocol diagnosed the disease state (cancer yes/no) at a statistically significant level. When using the abbreviated protocol, the diagnostic accuracy was maintained. All cancers were detected by the two radiologists with the abbreviated protocol (100% sensitivity), which was the equal to the full protocol. The specificity of the abbreviated protocol was significantly (p<0.05) lower for radiologists A (73.3%) and B (53.5%) when compared to the full protocol (100% for both). Conclusions: This study was the first of its kind performed locally creating a baseline for further investigations and adding to the body of knowledge. Despite limitations, it demonstrated that the abbreviated protocol had equal diagnostic accuracy to the full protocol in the detection of lobular carcinoma.