An approach based on strain-compounding technique and ultrasound Nakagami imaging for detecting breast microcalcifications

The usefulness of breast ultrasound could be extended by improving the detection of microcalcifications by being able to extract and enhance true microcalcifications whilst simultaneously eliminating hyperechoic spots that can lead to false-positive detections of microcalcifications (false-microcalcifications). This study investigated the use of a strain-compounding technique with Nakagami imaging to provide information associated with scatterer and elastic characteristics of tissues when attempting to identify microcalcifications and false-microcalcifications. To validate this concept, raw data of ultrasound backscattered signals were collected from 20 lesions with suspicious microcalcifications (15 microcalcifications and 5 false-microcalcifications verified by mammography and ultrasound-guided biopsy). For each region in which microcalcifications were suspected, estimates of the mean Nakagami parameter (m_avg) in the strain-compounding Nakagami images were normalized to those of the corresponding reference Nakagami images. Receiver operating characteristic (ROC) curve analysis was adopted to assess the diagnostic performances. The results demonstrated that the normalized m_avg estimates for microcalcifications and false-microcalcifications were 0.98±0.12 and 2.11±0.30 (p<;0.01), respectively. The mean area under the ROC curve was 0.99 with a 95% confidence interval of 0.94-1.00. These findings indicate that the strain-compounding Nakagami imaging method is effective at discriminating microcalcifications from false-microcalcifications, and thus can provide more clues and more detailed information for breast tumor characterizations.