Videodensitometry in the Examination of Focal Breast Lesions after Injection of an Ultrasound Contrast Agent

Abstract

Background: The present investigation aimed at assessing the possibility of distinguishing between malignant and benign breast lesions by measuring the signal intensity in vessels of the suspect lesions over time after administration of the ultrasound contrast agent Levovist®. Materials and Methods: Levovist® was administered intravenously to 21 patients with breast cancer and 12 patients with a benign breast lesion. In the subsequent ultrasound investigation (Color Power Angiography) the resulting increase in brightness over time in the vessels of the lesions was measured using the videodensitometry method. From the calculated time-brightness curves, the time to maximum brightness (T_max), time to 90% of maximum brightness (T_90%), maximum brightness and other time and brightness parameters were determined. The data were analyzed by means of the Mann-Whitney-Wilcoxon test. Additionally, the sensitivity and specificity were calculated for a sequence of cut-off levels for T_90%, T_max, maximum brightness and wash-in wash-out parameters. Results: The differences between the benign and the malignant lesions for the parameters T_max and T_90% were statistically significant. The malignant foci showed a significantly more rapid in-flow of the contrast agent (p=0.006) than the benign lesions. The wash-in wash-out time for Levovist® was significantly shorter for the malignant lesions than for the benign lesions (p=0.02). The time difference in attaining maximum brightness was not significant (p=0.14). The specificity and sensitivity made a more precise differentiation between benign and malignant tumors possible. Conclusion: The use of a contrast agent in Doppler ultrasound enhances the diagnostic reliability in distinguishing between malignant and benign lesions, justifying the use of a contrast agent with a high specificity (92%) such as Levovist®. However, invasive pre-operative methods such as punch biopsy are not, thereby, rendered unneccessary. It is possible that the combination of Levovist® and videodensitometry will make it possible to increase the specificity of breast cancer diagnosis.