Characterization of benign and malignant solid breast masses: harmonic versus nonharmonic 3D power Doppler imaging.

The aim of this study was to compare the diagnostic performance of nonharmonic ultrasound (US) and tissue harmonic imaging (THI) using three-dimensional (3D) power Doppler sonographic technique to classify benign and malignant breast tumors by vascularization. From January 2003 to February 2004, we evaluated 200 patients and one of lobular carcinoma in situ was excluded from the malignant category. One hundred and ninety-nine subjects were enrolled. All subjects with one or more breast masses were studied with 3D power Doppler US nonharmonic and harmonic technologies. Sixteen of 199 subjects were excluded because masses exceeded 3 cm limit of our US probe's footprint (n = 5) or no harmonic Doppler information (n = 11). A total of 97 benign and 86 pathologically proven malignant breast tumor images were analyzed. 3D power Doppler US imaging was performed using a Voluson730 US system. Three histogram indices, the vascularization index (VI), flow index (FI) and vascularization-flow index (VFI), on both nonharmonic and harmonic images were calculated for the intratumor and for shells with an outside thickness of 3 mm surrounding the breast lesion. A multilayer perception (MLP) neural network classifier used the vascularity indices to determine whether the breast tumors are benign or malignant. The receiver operating characteristic (ROC) curves are performed to estimate the diagnostic performances for nonharmonic and harmonic methods. ROC curve analysis used overall age, volume, VI, FI and VFI for both intratumor and shells with an outside thickness of 3 mm surrounding the breast lesions in nonharmonic US and THI. The area under the ROC curve (A(Z)) was 0.9086 and 0.9009 (p = 0.3770). The sensitivity was 90.7% and 83.7% (p = 0.72), respectively, and the specificity was 92.8% and 92.8% (p = 1.00), respectively. In conclusion, the performance of 3D power Doppler US with respect to the characterization of solid breast masses as benign or malignant was not significantly improved with tissue harmonic imaging.