Application value of MRI directed "second-look" ultrasound for breast cancer not detected initially on ultrasound

Objective To evaluate the clinical application value of MRI-guided "second-look" ultrasound and analyze the causes of missed diagnosis performed by ultrasound. Methods A retrospective review was performed on 52 breast cancer patients (80 lesions), who underwent mamography, MRI and MRI-directed "second-look" ultrasound. All lesions were proven by histopathology. The imaging information were analyzed by using the breast imaging reporting and data system lexicon and the breast volumes was measured on mamography. Results All of the 52 patients were proven to have breast cancer by MRI-guided "second-look" ultrasound. Seven patients had bilateral synchronous breast cancer, 21 patients had multifocal breast cancer and 80 breast cancer lesions were found by MRI-directed ultrasound.Thirty three lesions were mass MRI lesions, the range of the largest diameters was 0.4 to 2.9 cm, average (1.6±0.7) cm. Forty seven lesions were non-mass MRI lesions, the range of the largest diameters was 0.7 to 10.3 cm, average (3.0±2.3) cm. The breast volumes of 19 lesions (23.8%) were ≤ 350 cm3, 61 lesions(76.2%) were>350 cm3. Twenty six lesions (32.5%) had homogeneous background echotextures, fifty four (67.5%) lesions had heterogeneous background echotextures. Conclusions MRI-guided ultrasound has great value of clinical application in helping analyzing the reason of missed breast cancer on ultrasound. Key words: Breast neoplasma; Magnetic resonance imaging; Second-look ultrasound