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Tomas Ortiz Basso, Rodolfo Luis Vigo, Maria Felisa Shokida, Joaquin Miguel Gonzalez Barlatay, carla pagano, Guillermo Hernandez Gauna, Eduardo Jorge Premoli; New uses of short tau inversion recovery magnetic resonance imaging for the evaluation of Graves Ophthalmopathy activity. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5614.
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© ARVO (1962-2015); The Authors (2016-present)
Evaluate if a patient with Graves Disease has an active ophthalmopathy is of great importance to take a therapeutic decision. The edema of the extraocular muscles can be measured using Short Tau Inversion Recovery (STIR) Magnetic Resonance Imaging (MRI). But some cases present more inflammation in fat tissue than in the muscles. There are no studies that evaluate orbital fat through this technique. The aim of the study was measure the orbital fat intensity of healthy individuals and to compare it with patients with Graves Ophthalmopathy (GO).
Patients over 18-year-old, who performed a brain STIR MRI for a cause different than GO, were included. They were compared with patients who suffered active GO. Exclusion criteria were: orbitopathy of other etiology, orbital or palpebral surgery during the 6 previous months, treatment with corticosteroids or radiotherapy during the 6 previous months.After signing the informed consent, MRI was performed. The Signal Intensity Ratio (SIR) of the orbital fat was measured: dividing the orbital fat into 4 quadrants and calculated a proportion with the intensity of the subcutaneous adipose tissue, of close anatomic relation and similar structure, not affected by GO. The SIR of the muscle corresponds to the proportion between the area of higher signal of the extraocular muscles, and that of the left temporal muscle.
We compared 30 orbits of healthy individuals with 28 orbits of patients with mild and active GO. The average age was 52 years (SD 19,56) and 65% (n19) were women.The average SIR for the sum of quadrant of healthy people was 3,33 (SD 0,52; 95%IC 3,13-3,52) and of patients with GO was 3,27 (SD 0,55; 95%IC 3,05-3,48) (p 0,66). And the average of muscle SIR was 2,71 (SD 0,46; 95%IC 2,54-2,88) and 3,73 (SD 0,75; 95%IC 3,44-4,02) (p<0,01), respectability.
This is the first study that evaluated the SIR of the fat, it’s useful because some patient with GO just present a fat inflammation. We did not find difference between the SIR of orbital fat, probably because we included patient with just mild disease. In this study we set the SIR values for patient without GO. The combination of SIR of muscle and fat could help the ophthalmologist to detect the initial phase of GO, and quantify objectivity a therapeutic response.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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