US-guided diffuse optical tomography for breast lesions: the reliability of clinical experience

Purpose To prospectively assess the reliability of US-guided diffuse optical tomography (US-DOT) using interobserver agreement for the diagnosis of breast lesions with individual real-time imaging and to assess the interobserver agreement of conventional sonography (US) combined with US-DOT for differentiation between benignity and malignancy breast lesions. Materials and Methods An Institutional Review Board approved this study, and all subjects provided written informed consent. 122 breast lesions in 111 patients evaluated with USguided core biopsy were included. Assessments with US and US-DOT for cases subjected to biopsy were obtained by two radiologists using individual real-time imaging prior to biopsy and were prospectively recorded by each performer.With DOT, the total haemoglobin concentration (THC) for each breast lesion was measured. Histopathological results from USguided biopsies were used as a reference standard. To assess measurement interobserver agreement, the intraclass correlation coefficient (ICC) and the Bland-Altman plot were used for THC in US-DOTand the kappa values and ROC analysis were used to evaluate the diagnostic performances of the US BIRADS final assessment in US and combined US and US-DOT. Results Of 122 US-guided core biopsied lesions, 83 (68.0%) were diagnosed as benign, and 39 (32.0%) as malignant. Excellent correlation was seen in the THC in US-DOT (ICC score 0.796; 95% confidence interval, 0.708–0.857). The interobserver agreement in BI-RADS final assessment with US and US-DOT (almost perfect; κ=0.8618) was improved compared with that of US (substantial agreement, κ=0.6574). However, the overall areas under the ROC curve did not show significant differences between US and combined US and USDOT, 0.8894 and 0.8975, respectively (P=0.981). Conclusions The reliability of THC in US-DOT showed excellent correlation in overall real-time performance. Although the inter-observer agreement for BI-RADS final assessment of US was improved by using US-DOT, the performances of radiologists with respect to the characterization of breast masses as benign or malignant were not significantly improved with US-DOT.