Evaluation of spiculation and retraction patterns in coronal reconstructions in 3D Automated Breast Ultrasound (ABUS) improve differentiation between benign and malignant breast lesions

PURPOSE To investigate the value of coronal reconstructions of transversal 3D ABUS data in differentiation of benign from malignant breast lesions. METHOD AND MATERIALS This study received a waiver by the local ethics committee. For this reader study we obtained 96 3D ABUS casus with 37 malignant and 59 benign ultrasound guided core biopsied breast lesions. The localization of the lesions was done by a physician with 1 year 3D ABUS experience based on the primary radiology reports and biopsy results. The 3D ABUS view in which the lesion was best visible, was presented to 3 experienced breast radiologists with 2 years experience with 3D ABUS. They were first asked to detect and classify the most suspicious lesion in the view using the BIRADS lexicon and scoring system. A likelihood of malignancy (LOM) score between 0 and 100 was also requested. Thereafter the coronal reconstruction was shown and readers were asked to reassess the lesion. Spiculation and retraction in the coronal plane were scored on a five point scale (Spiculation and Retraction Severity Index (SRSI)). Subsequently LOM and BI-RADS scores could be adjusted. Az values for differentiation of benign from malignant lesions based on LOM scores were computed with DBM MRMC method. PearsonAC/a,!a,,C/s correlation coefficient between the reassessed LOM on the coronal reconstructions and SRSI was calculated for all readers. RESULTS Three readers respectively pointed out 92%, 97% and 92% of 37 cancers as the most suspicious lesion in the 3D ABUS acquisition. After evaluation of the coronal reconstructions, detected malignant lesions were not downgraded to BI-RADS 2, however, 7 benign lesions were downgraded from BI-RADS 3 to BI-RADS 2. After reevaluation the discrimination between benign and malignant lesions significantly improved from 0.84 (95% CI 0.76- 0.92) to 0.87(95% CI 0.80-0.94) (p=0.02). SRSI scores correlated significantly with the reassessed LOM scores for all readers, r = 0.85, 0.75 and 0.75, respectively (p<0.001). CONCLUSION Coronal reconstructions in 3D ABUS significantly improve the differentiation between benign and malignant breast lesions, by providing new visual information on breast cancer spiculation and retraction. CLINICAL RELEVANCE/APPLICATION Better differentiation between malignant and benign breast lesions may reduce false positive biopsies in evaluation of automated breast ultrasound