BackgroundThis study aimed to evaluate the feasibility of contrast-enhanced ultrasound (CEUS) and CEUS-guided interventions in the diagnostics of MRI visible targeted US occult breast lesions.Patients and methodsThis retrospective study examined 10 females with 10 occult, MRI only detected breast lesions between July 2014 and April 2017. Targeted second look US followed by CEUS with 2.4 ml of SonoVue® were performed for all of the lesions. After positive CEUS localization the same dose was repeated for confirmation and CEUS-guided interventions were performed.ResultsMRI revealed 8 mass lesions with a mean size of 9 mm (range 5–16 mm) and 2 non-mass enhancing lesions of 10 and 20 mm in largest diameters. Targeted US revealed no morphological correlate for the lesions. Five out of 10 lesions (50%) were visible on CEUS. CEUS-guided core biopsy was performed on 4 lesions and 1 was marked with a clip for later surgical removal. Histopathological analysis confirmed 4 of them to be malignant. Three out of 5 nonvisible lesions on CEUS underwent MRI-guided interventions, 1 lesion was scheduled for follow-up as it was non-amenable for MRI biopsy, and 1 lesion was biopsied under US-guidance. Three of these nonvisible lesions on CEUS were confirmed to be malignant.ConclusionsBased on our preliminary results, CEUS is a feasible tool for detecting many MRI only visible breast lesions, resulting in a more cost effective and less time-consuming practice. It is a more convenient alternative than MRI guided biopsy and has the potential to be included in the diagnostic algorithm which evaluates MRI only visible breast lesions.

Mammographic breast density (MBD) is the most commonly used method to assess the volume of fibroglandular tissue (FGT). However, MRI could provide a clinically feasible and more accurate alternative. There were three aims in this study: (1) to evaluate a clinically feasible method to quantify FGT with MRI, (2) to assess the inter-rater agreement of MRI-based volumetric measurements and (3) to compare them to measurements acquired using digital mammography and 3D tomosynthesis. This retrospective study examined 72 women (mean age 52.4 ± 12.3 years) with 105 disease-free breasts undergoing diagnostic 3.0-T breast MRI and either digital mammography or tomosynthesis. Two observers analyzed MRI images for breast and FGT volumes and FGT-% from T1-weighted images (0.7-, 2.0-, and 4.0-mm-thick slices) using K-means clustering, data from histogram, and active contour algorithms. Reference values were obtained with Quantra software. Inter-rater agreement for MRI measurements made with 2-mm-thick slices was excellent: for FGT-%, r = 0.994 (95% CI 0.990-0.997); for breast volume, r = 0.985 (95% CI 0.934-0.994); and for FGT volume, r = 0.979 (95% CI 0.958-0.989). MRI-based FGT-% correlated strongly with MBD in mammography (r = 0.819-0.904, P < 0.001) and moderately to high with MBD in tomosynthesis (r = 0.630-0.738, P < 0.001). K-means clustering-based assessments of the proportion of the fibroglandular tissue in the breast at MRI are highly reproducible. In the future, quantitative assessment of FGT-% to complement visual estimation of FGT should be performed on a more regular basis as it provides a component which can be incorporated into the individual's breast cancer risk stratification.

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