Magnetic resonance imaging as a part of standard clinical care for calculating breast implant volume: a validation study on 110 in-situ breast implants

Breast implants are widely used by plastic surgeons for both reconstructive and cosmetic procedures. Women with implants are advised to have Magnetic Resonance Imaging (MRI) to check breast implant integrity. In case revision surgery is needed, implant volume and type are often unknown. MRI could then be used for measuring in-situ breast implant volume. This information is useful when planning revision surgery. A retrospective review of 69 MR images with 110 silicone breast implants was performed. Two independent, blinded radiology residents performed measurements on the T2-weighted images. Contours of the breast implant were delineated as a region of interest (ROI) and the software Syngo.via (Siemens Healthcare GmbH) generated a continuous volume of interest (VOI), computed in cubic centimeters. Gold standard volume was retrieved from surgery reports after explantation. The average implant volume was 354 cc (SD 119). The absolute difference between implant size and MRI measurement was 38 cc (SD 23) and the relative difference was 10.8% (SD 7). The differences were significantly different (p < 0.001). There was a strong linear regression between the two variables. Interobserver reliability was excellent (ICC = 0.992). We conclude that MRI as a volumetric tool for measuring implant volume in-situ is a reliable tool and can easily be applied in clinical practice. Based on 110 measurements, MRI overestimated implant volume by 10.8% but correlated strongly with the gold standard. This MRI technique is simple to learn, reproducible, and can be added as part of standard care in breast implant care in plastic surgery. Level of Evidence: Level III, diagnostic study.