Contrast-enhanced Ultrasound is Helpful in the Differentiation of Malignant and Benign Breast Lesions

Objective: To evaluate the significance of contrast-enhanced ultrasound (CEUS) examination in differential diagnosis of malignant and benign breast lesions.

Methods: Seventy-one patients with seventy-six breast tumors are selected randomly. CEUS examinations were performed before and after bolus injection of the contrast agent SonoVue (Bracco, Milan, Italy). Specific sonographic quantification software, Qontrast, was adopted to determine the morphology of vessels. Wash-in and wash-out parameters of each lesion were assessed for both procedures.

Results: The final histopathological findings distinguished 45 malignant and 31 benign from all of the lesions. Following SonoVue administration different perfusion phases could be identified: early (0-1min), mid (1-4min) and late (4-6min) phases. In the early phase, CEUS identified 91.1% of malignant tumors characterized by a claw-shaped enhancement, while 83.9% of benign tumors had a homogeneous enhancement, with a statistically significant difference between the two enhancement patterns (chi(2)=43.16, P<0.01). Moreover, contrast medium persistence in the late phase was helpful in the identification of benign and malignant tumors (chi(2)=46.88, P<0.01): contrast medium was present in 88.9% of malignant tumors, while in only 9.7% of the benign tumors. The study showed that various parametric imaging color maps for peak intensity and time to peak were mostly suggestive of malignancy, while quite uniform peak intensity and time to peak of color maps were the characteristic of benign tumors. The study also found that malignant lesions presented with a higher maximum intensity signal than benign ones (P<0.05) on the time-intensity curves.

Conclusions: CEUS cooperating with conventional US shows improved accuracy in differentiating between malignant and benign breast tumors. It could be a reliable diagnostic method of breast lesions.