Abstract
Purpose :
To verify the accurity of a new MRI 3D reconstruction technology and evaluate the severity of dysthyroid optic neuropathy (DON) .
Methods :
Using butter and chicken muscle, we simulated the orbital soft tissue and measured the their volume based on the MRI scan and 3D reconstruction software, the data were compared with the real volume gained by manual measurement. Then patients diagnosed as thyroid-associated ophthalmopathy (TAO) with or without DON, and healthy participants were recruited. All orbital fat and rectus of participants were measured by the MRI 3D reconstruction. Visual function, including visual best-corrected visual acuity (BCVA), visual field (VF) and visual evoked potential (VEP), were assessed for all TAO patients. Futhermore, we correlated the fat volume, rectus volume and the ratio of rectus and fat volume with the parameters of visual function.
Results :
The intraclass correlation coefficient (ICC) between the 3D reconstruction data and real volume data of fat and muscle was 0.963 and 0.986. Compared with the healthy participants and the TAO patients without DON, the DON rectus volume of DON patients increased statistically significantly (P<0.05) and the ratio of rectus and fat was also increased (P<0.05). In TAO patients, the ratio were well correlated with BCVA (r=0.696) and mean defection of visual field (r=-0.601). Howerer, the fat volume and the rectus volume were not correlated with the visual function parameters significantly.
Conclusions :
The new MRI 3D reconstruction technology can measure the orbital soft tissue precisely. DON patients have increased rectus volume and high ratio of rectus and fat. And the ratio would be a ideal parameters to evluate the severity of DON.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.