Magnetic resonance classification proposal for fibrous capsules in breast silicone implants

Abstract

Objective: To propose a new classification system for evaluating fibrous capsules around silicone implants using magnetic resonance.

Methods: We retrospectively evaluated 90 consecutive patients who underwent breast MRI scans at a single center from February to March 2022. All patients with silicone implants and contrast dynamic sequences were included. Two radiologists classified the fibrous capsules according to the proposed classification in four grades. Interobserver variability was calculated for the final score. For comparison purposes, the inter-rater agreement of background parenchymal enhancement and the amount of fibroglandular tissue were also calculated.

Results: Reader 1 classified 2 (2.2) fibrous capsules as grade 1, 7 (7.8) as grade 2, 18 (20.0) as grade 3, and 63 (70.0) as grade 4, whereas reader 2 classified 1 (1.1), 9 (10.0), 24 (26.7), and 56 (62.2) fibrous capsules, respectively, for each grade. The interobserver agreement for fibrous capsule classification was moderate (ĸ = 0.65). The inter-rater agreement of background parenchymal enhancement and amount of fibroglandular tissue were fair: ĸ = 0.50 and ĸ = 0.44, respectively.

Conclusion: Our study proposes classifying FC by MRI in patients with SI to standardize the description and classification of the findings with good interobserver agreement.

Keywords: Classification; Fibrous capsule; Granuloma; Implant; Silicone.