E9 ultrasound system

All breast ultrasound examinations were performed by two sonographers (JW and YW with more than 5 years’ experience in breast ultrasound imaging) by using LOGIQ E9 ultrasound system with a 6-15L linear array probe and Siemens Acuson S2000 with a 6-18L linear array probe with radial, transverse, and longitudinal scans on both breasts. Ultrasound was further utilized to scan breast tumor from multiple angles and sections to absorb the overall information. In addition, we carefully observed the shape, size, blood supply and echo of the tumor. The scan parameters were consistent among patients: image depth was about 4.0 cm; gain was about 50%; and focus paralleled to the tumor. The image of the largest section of the breast tumor with the clearest imaging was saved as the format of Digital Imaging and Communications in Medicine to maximize the preservation of the image information. A two dimensional region of interest (ROI) that covered the whole lesion was manually delineated on the selected largest section of the breast tumor by using ITK-SNAP software (open source software; http://www.itk-snap.org). This was performed independently by an experienced sonographer (YJ with more than 5 years’ experience in breast ultrasound imaging) blinded to patients’ postoperative IHC.

Preoperative ultrasound scannings were carried out by two sonographers (more than 5 years’ experience in the breast ultrasound). All breasts of the patients were scanned using LOGIQ E9 ultrasound system with a 6-15L linear array probe and Siemens Acuson S2000 with a 6-18L linear array probe. The ultrasound images were stored as the format of Digital Imaging and Communications in Medicine. A sonographer with no information about the lesion’s histopathology selected the largest plane of each breast lesion and delineated a two dimensional region of interest (ROI) that covered the whole lesion by using ITK-SNAP software (open source software; http://www.itk-snap.org).