Comparison between different imaging techniques in the evaluation of malignant breast lesions: can 3D ultrasound be useful?

PURPOSE: This study was done to assess the feasibility of three-dimensional ultrasonography (3D-US) for volume calculation of solid breast lesions. MATERIALS AND METHODS: The volumes of 36 malignant lesions were measured using conventional 2D-US, 3D-US and magnetic resonance imaging (MRI) and compared with that obtained with histology (standard of reference). With 2D Ultrasouns, volume was estimated by measuring three diameters and calculating volume with the mathematical formula for spheres. With 3D-US, stored images were retrieved and boundaries of masses were manually outlined; volume calculation was performed with VOCAL software. For MRI, volume measurements were obtained with special software for 3D reconstructions, after each lesion had been manually outlined. Histology measured the three main diameters and the volume was estimated using the mathematical formula for spheres. Interclass correlation coefficient (ICC) and Bland-Altman plots were used to assess agreement between the volumes measured. RESULTS: ICC indicated that a good level of concordance was identified between 3D-US and histology (0.79). According to the Bland-Altman analysis, limits of agreement of mean differences of the volumes measured with the three imaging modalities were comparable with histology: -2÷1.5 cm3 for 3D-US; -2.3÷1.3 cm3 for 2D-US and -2.2÷1.6 cm3 for MRI. CONCLUSIONS: 3D-US is a reliable method for the volumetric assessment of breast lesions. 3D-US is able to provide valuable information for the preoperative evaluation of lesions.