Imaging of the Silicone Implant with a 3D SPACE MR Sequence: The Accuracy for Estimating Implant Volume and Reconstructing Implant Deformation in Breast Surgery.

Abstract

The study is to assess the accuracy and reliability of 3D simulated magnetic resonance imaging with SPACE sequence for estimating implant volume and reconstructing implant deformation, which may assist in the diagnosis of implant complications and making individualized surgical plans for these patients. MRI examinations of ten silicone implants were performed with T2, H2O-excitation SPACE sequence (T2-spc-H2O) and silicone-excitation SPACE sequence (T2-spc-Silicone) to find the most accurate method to estimate implant volume by ITK-SNAP. The effect of implant deformation and voxel size of silicone-excitation SPACE sequence on volume measurement was investigated. Thirteen normal patients and ten patients with implant complications (Wuhan Tongji Hospital from March 2017 to May 2019) were enrolled for testing the accuracy and reliability of 3D simulated MRI with silicone-excitation SPACE sequences for volume measurement and reconstructing implant deformation in patients. The absolute volume differences of T2-spc-Silicone group were significantly less than T2-spc-H2O and T2 group (6.28 vs. 23.27 vs. 42.19mL, P < 0.05) in vitro. No significant difference was found between the normality group and the deformation group for estimating the volume of implants. Besides, the voxel size of T2-spc-Silicone from 0.5 × 0.5 × 0.5mm to 5.0 × 5.0 × 5.0mm did not significantly affect the accuracy of volume measurement of the implants in deformation state. However, 3D images of the implant became blurred with the voxel size increased. With the voxel size larger than 1.5 × 1.5 × 1.5mm, the scores of image quality decreased significantly. The number of folds could not be identified accurately with the voxel size larger than 2.0 × 2.0 × 2.0mm. In normal patients, the measurement errors of T2-spc-Silicone were around 10mL. In the patients with implant complications, there was no significant difference between measured volume and the actual volume of implants. Moreover, implant deformations were clearly presented by T2-spc-Silicone with the voxel size of 1.0 × 1.0 × 1.0mm. The results showed excellent intraobserver reliability (ICC = 0.997 > 0.8), and internal consistency ranged from 0.986 to 0.997 (P < 0.001). The method to measure implant volume by 3D simulated magnetic resonance imaging with T2-spc-Silicone sequence had possessed desirable accuracy and reliability. The deformation of the implant and the voxel size of the T2-spc-Silicone sequence didn't exhibit a significant effect on the accuracy of the measurement. T2-spc-Silicone with voxel size less than 2.0 × 2.0 × 2.0mm could be used for 3D reconstruction of the implant deformation. The 1.0 × 1.0 × 1.0mm was a suitable voxel size to reconstruct implant deformation clearly and quickly. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .