Jie Shen1, Wei Jiang1, Yaosheng Luo1, Qiuyue Cai1, Zhangfang Li1, Zhiyi Chen1, Shidi Hu1, Lei Tang2. 1. Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China. 2. Department of Anatomy, Southern Medical University School of Basic Medical Science, Guangzhou, China.
Abstract
OBJECTIVE: Effective management of thyroid-associated ophthalmopathy (TAO) requires precise identification of the disease activity period as it is responsive to immunosuppressive treatment. Quantitative evaluations of orbital soft tissue are useful for analysing disease stages. We aimed to establish a method for orbital soft tissue volume calculation based on magnetic resonance imaging (MRI) data using 3D reconstruction technology. Furthermore, we validated the accuracy and precision of this method and investigated volume differences between patients with TAO and healthy individuals. MATERIALS AND METHODS: Using Mimics software for 3D reconstruction based on orbital MRI data, we quantitatively measured orbital fat volume (FV) and extraocular muscle volume (MV) using a manual phantom, and in patients with TAO and healthy volunteers (n = 10 each). The phantom was made using a combination of butter and chicken muscle and 2 observers measured its volume. Volume calculations were compared to a previously established standard volume. One observer measured a typical TAO case 10 times to calculate intra-observer variability while 3 observers independently measured 10 patients with TAO each to calculate interobserver variability. Orbital soft tissue volumes between 10 patients with TAO and 10 healthy individuals were compared. RESULTS: The precision of calculations for the phantom between the 2 observers varied from -4.60% to -2.78% for FV and between -4.13% to 0.71% for MV. Mean differences among repetitive calculations were lower than 4%, except during measurement of MV, which was 5.84%. The intraclass correlation coefficient varied from 0.976 to 0.996. FV was 15.53 ± 3.06 mL in patients with TAO and 11.32 ± 1.68 mL(P = .001)in healthy individuals, while MV was 3.19 ± 0.82 mL in patients with TAO and 2.45 ± 0.57 mL(P = .030)in healthy individuals. CONCLUSIONS: This method of calculating orbital soft tissue volumes based on MRI data and 3D reconstruction is both reliable and accurate as it yielded significant differences in tissue volume between patients with TAO and healthy individuals.
OBJECTIVE: Effective management of thyroid-associated ophthalmopathy (TAO) requires precise identification of the disease activity period as it is responsive to immunosuppressive treatment. Quantitative evaluations of orbital soft tissue are useful for analysing disease stages. We aimed to establish a method for orbital soft tissue volume calculation based on magnetic resonance imaging (MRI) data using 3D reconstruction technology. Furthermore, we validated the accuracy and precision of this method and investigated volume differences between patients with TAO and healthy individuals. MATERIALS AND METHODS: Using Mimics software for 3D reconstruction based on orbital MRI data, we quantitatively measured orbital fat volume (FV) and extraocular muscle volume (MV) using a manual phantom, and in patients with TAO and healthy volunteers (n = 10 each). The phantom was made using a combination of butter and chicken muscle and 2 observers measured its volume. Volume calculations were compared to a previously established standard volume. One observer measured a typical TAO case 10 times to calculate intra-observer variability while 3 observers independently measured 10 patients with TAO each to calculate interobserver variability. Orbital soft tissue volumes between 10 patients with TAO and 10 healthy individuals were compared. RESULTS: The precision of calculations for the phantom between the 2 observers varied from -4.60% to -2.78% for FV and between -4.13% to 0.71% for MV. Mean differences among repetitive calculations were lower than 4%, except during measurement of MV, which was 5.84%. The intraclass correlation coefficient varied from 0.976 to 0.996. FV was 15.53 ± 3.06 mL in patients with TAO and 11.32 ± 1.68 mL(P = .001)in healthy individuals, while MV was 3.19 ± 0.82 mL in patients with TAO and 2.45 ± 0.57 mL(P = .030)in healthy individuals. CONCLUSIONS: This method of calculating orbital soft tissue volumes based on MRI data and 3D reconstruction is both reliable and accurate as it yielded significant differences in tissue volume between patients with TAO and healthy individuals.
Authors: Georgios Bontzos; Michael Mazonakis; Efrosini Papadaki; Thomas G Maris; Styliani Blazaki; Eleni E Drakonaki; Efstathios T Detorakis Journal: Natl J Maxillofac Surg Date: 2020-06-18