Introduction: Opto-acoustics (OA) is a true fusion imaging technology that combines dual energy laser optic functional imaging with real time gray scale ultrasound morphologic imaging. The laser optic component uses two wavelengths that have been chosen to optimally demonstrate oxygenated and deoxygenated hemoglobin. The color-coded laser optic images are co-registered and temporally interleaved with real time gray scale images. OA fusion imaging benefits from the combination of the high contrast resolution of dual wavelength laser optics and the higher spatial resolution and penetration of gray scale ultrasound. OA can demonstrate both tumor neovascularity and the relative degrees of oxygenation-deoxygenation within breast mass and within the surrounding tissues.
Methodology: A series of 68 prospective patients with undiagnosed breast masses going to biopsy were evaluated before biopsy with a handheld device combining ultrasound co-registered with OA for the visualization of pre-defined internal and external features. The internal features included vascularity (V), blush (BU), and blood (BL) accumulation while external features included boundary zone vascularity and blush (BZ) and peri-tumoral radiating vessels (RV); each were scored on a 0-5 ordinal scale and were summed to get a total internal score, total external score, and a total score. A two-sided exact Jonckheere-Terpstra test was used to test the relationship between increasing scores and higher cancer grade.
Results: The study population consisted of 29 fibroadenomas (FAs) as well as 10 invasive ductal carcinoma (IDC), grade 1, 11 IDC grade 2, and 18 IDC grade 3 cases. OA Total (two-sided p = 3×10−8) and OA Total Internal (two-sided p = 6×10−9) were highly significant but OA Total External was not statistically significant; OA Total and OA Total Internal Features were highly related to histology with lower scores for FAs increasing progressively to highest scores for IDC 3. Moreover, all three internal OA features were highly significant: (1) V (two-sided p = 10−7), BU (two-sided p = 3×10−8), and BL (two-sided p = 5×10−6).
Cumulative contribution of each internal feature to the total internal score was also assessed for each histopathology subgroup to confirm independent contribution to the OA Total Internal Score. Pairwise correlations explained no more than 56% of the total variance.
Conclusions: We have established the prognostic value of OA Total and OA Internal Features as well as the validation of the contributions of each OA Internal Feature. Using the combination of individual internal and external OA features not only helps distinguish benign from malignant masses, but helps stratify malignant lesions by histologic grade. These abilities could be useful both for diagnosis and for monitoring non-surgical treatment of malignant masses.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-13.