Contrast-enhanced ultrasound in the characterisation of breast masses: utility of quantitative analysis in comparison with MRI

To evaluate the reliability of contrast-enhanced ultrasound quantitative analysis (CE-US) in characterizing breast lesions, in comparison with MRI. Thirty-nine patients with breast lesions BI-RADS 3-5 at US or mammography underwent CE-US and MRI. All lesions underwent histological and quantitative enhancement evaluation with both imaging methods. B-mode US, colour/power Doppler US and CE-US were used; an amplitude and phase modulation technique (CPS) read the signals produced by microbubbles and dedicated software produced the following parameters on time/intensity (T/I) curves: peak %, time to peak (TTP), mean transit time (MTT), regional blood volume (RBV) and regional blood flow (RBF). Student's t test was used to calculate the diagnostic accuracy of CE-US parameters compared with histological results. MRI (1.5 T) was performed before and after bolus gadolinium enhancement. Time/intensity curves were generated for all nodules and Fischer's multimodal score was used to classify them. Pathology showed 43 nodules (11 benign; 32 malignant). Peak and RBF were the most significant parameters in differential diagnosis, with p values of 0.02 and 0.004, respectively. Positive predictive value (PPV) of CE-US evaluation was 91%, negative predictive value (NPV) was 73% with a high concordance index (k = 0.59) with MRI. CE-US quantitative analysis offers an objective and reproducible assessment of lesion vascularisation, with good correlation with the results of MRI.