Breast lesion characterization with contrast-enhanced US. Work in progress.

Purpose: To characterise breast lesions on the basis of microcirculation features detected with contrast-enhanced US.

Materials And Methods: Thirty-six patients aged 42-63 years (mean age 55 years) with a single breast lesion previously detected at standard mammography were studied. All US examinations were performed using an ATL HDI 5000 ultrasound device with a 5-10 MHz linear-array transducer, before and after administration of ultrasound contrast medium Levovist (Schering(R), Berlin) was administered by bolus injection (2 ml/s) via a 20 G catheter probe. The mechanical index was set to high to obtain instant rupture of the microbubbles under insonation. Intensity/time curves of the transient scattering in the region of interest (ROI) after contrast administration were extrapolated. The areas under the ROI curves were also evaluated to quantitatively assess the scattering.

Results: The US baseline study and colour Doppler US identified 19 benign lesions (15 histologically proven) and 17 malignant lesions (16 histologically proven). The administration of contrast medium did not improve the specificity of the examination. Only by plotting the intensity/time curves of the regions of interest (ROI) and evaluating the areas under the ROI curves, was a significant correlation detected between US and histopathologic diagnosis.

Conclusions: Although further evaluation on a larger series is needed, the analysis of breast lesions by contrast-enhanced perfusion US seems to be a promising technique. Perfusion US can usefully complement high-frequency US, especially when mammography is inconclusive.