Six-year prospective evaluation of second-look US with volume navigation for MRI-detected additional breast lesions

OBJECTIVE: The aim of this study is to present a 6-year prospective evaluation of second-look ultrasound (US) using volume navigation (V Nav) for MRI-detected additional breast lesions. METHODS: After IRB approvals in both institutions, 1930 consecutive prone MRI breast examinations in 1437 patients were prospectively evaluated. All patients with an MRI-detected additional lesion underwent second-look US, and if occult, contrast-enhanced MRI in supine position was performed for US and MRI co-registration. For patients with breast hypertrophy, MRI-guided biopsy was performed directly. Pathologic examination was the standard of reference. One-way ANOVA and chi-square tests were used. RESULTS: In 490 MRI examinations (25.4%, 490/1930), at least one additional breast lesion was detected for a total of 722 only MRI-detected lesions. Second-look US identified 549 additional lesions (23 ± 8 mm); 362 (65.9%, 362/549) proved benign at pathology and 187 (34.1%, 187/549) malignant. Second-look US with V Nav identified 151 additional lesions (17 ± 9 mm, p = n.s.); 67 (44.4%, 67/151) proved benign at pathology and 84 (55.6%, 84/151) malignant. MRI-guided biopsy was performed on 22 additional breast lesions (22 ± 8 mm, p = n.s.); pathology revealed 20 (90.9%, 20/22) benign lesions and 2 (9.1%, 2/22) malignant ones. Mass lesions were significantly higher in the second-look US group (p < 0.001). No significant difference in lesion dimension was found between the three groups (p = 0.729). CONCLUSIONS: Second-look US with V Nav can be effective in detecting a large number of additional breast lesions occult at second-look US and to biopsy a significant number of malignant lesions safely and irrespective of distance from skin or lesion position. KEY POINTS: • Second-look US with volume navigation is effective in detecting occult additional lesions. • Permits safe biopsies irrespective of position and depth • Reduces the need for MRI-guided biopsy.