Scar or recurrence - comparison of MRI and color-coded ultrasound with echo signal amplifiers

Purpose: MRI is the most reliable method to differentiate scar and recurrent carcinoma of the breast after surgical treatment. This study compares MRI and color-coded ultrasound with and without echo signal amplifier (ESA). Materials and Methods: Forty-two patients with suspected recurrent tumors were enrolled in this prospective study, with 38 patients after breast conserving therapy and 4 after mastectomy. All patients had a clinical examination, mammography (n=38), real time ultrasound (US), color-coded ultrasound without and with ESA (Levovist trademark, Schering, Berlin), and dynamic MRI. The criteria used for duplex ultrasound were tumor vascularisation and flow pattern. The results were compared with histologic findings or the results of follow-up examinations for at least 12 months. Results: The detection of penetrating or central vessels proved to be an accurate sign of malignancy in duplex ultrasound. With the application of ESA, additional vessels were detected within the lesions, increasing the diagnostic accuracy (83% with ESA versus 79% without ESA). The sensitivity of color-coded ultrasound improved from 64% to 86% with echo signal amplifier. The specificity was 86% without and 82% with echo signal amplifier. MRI was found to have a sensitivity fo 100% and a specificity of 82%. The same 5 lesions were false positive on MRI and color-coded US after Levovist trademark. No lesion without signs of vascularity within or in its vicinity was malignant. Conclusion: Color-coded ultrasound seems to be a promising method in the differentiation between scar and recurrence. Lesions with penetrating or central vessels have a high probability of being malignant, whereas lesions without any signs of vascularity inside or nearby have a high probability of being benign. Advantage of contrast-enhanced US is its ubiquitous availability. (orig.)