Automated breast ultrasound: lesion detection and BI-RADS classification--a pilot study

Evaluation of an automated breast ultrasound system (ABUS) regarding the detection and classification of breast lesions according to BI-RADS.

Women were selected for the study who had unclear findings in breast diagnosis performed elsewhere (palpation, sonography or mammography) and who were referred for further work-up. All patients received a hand-held ultrasonography (HHUS) with a 13 MHz transducer, clinical examination and mammography of both breasts. Additionally, the affected breast received the ABUS (SomoVuTM, U-Systems, Inc., San Jose, CA, USA; EC Representative: Siemens, Erlangen, Germany) which was performed with an 8 MHz transducer. Five radiologists independently evaluated the ABUS images regarding lesion detectability. All detected lesions were classified according to BI-RADS assessment. The examiners had no knowledge of the patients' clinical examination or of the result of the mammography or the HHUS. Results of the ABUS were compared to HHUS.

35 women were included in the study. 25 BI-RADS 4 or 5 lesions had further histological (n = 23) or cytological (n = 2) work-up which revealed 13 malignant and 12 benign findings. The size of all lesions ranged from 6 to 32 mm (median 14 mm). With the ABUS all examiners detected 29 to 30 lesions while HHUS revealed 30 lesions. One suspicious area in HHUS was not reported by any of the five examiners with the ABUS. Histology of this area revealed mastopathic disease. No benign lesion was classified as BI-RADS 5 with the ABUS or HHUS. All breast cancers were found with the ABUS by all examiners and correctly classified as BI-RADS 4 or 5. There was good agreement regarding BI-RADS classification of HHUS and ABUS for the five different examiners with Kappa values between 0.83 and 0.87.

These preliminary results show that the ABUS allows detection of solid and cystic lesions and their BI-RADS classification with a high reliability in a selected patient group.