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Extraocular muscle sampled volume in Graves’ orbitopathy using 3-T fast spin-echo MRI with iterative decomposition of water and fat sequences

BACKGROUND: Current magnetic resonance imaging (MRI) techniques for measuring extraocular muscle (EOM) volume enlargement are not ideally suited for routine follow-up of Graves’ ophthalmopathy (GO) because the difficulty of segmenting the muscles at the tendon insertion complicates and lengthens the...

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Detalles Bibliográficos
Autores principales: Garau, Ludovico M, Guerrieri, Daniele, De Cristofaro, Flaminia, Bruscolini, Alice, Panzironi, Giuseppe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: SAGE Publications 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039898/
https://www.ncbi.nlm.nih.gov/pubmed/30013794
http://dx.doi.org/10.1177/2058460118780892
Descripción
Sumario:BACKGROUND: Current magnetic resonance imaging (MRI) techniques for measuring extraocular muscle (EOM) volume enlargement are not ideally suited for routine follow-up of Graves’ ophthalmopathy (GO) because the difficulty of segmenting the muscles at the tendon insertion complicates and lengthens the study protocol. PURPOSE: To measure the EOM sampled volume (SV) and assess its correlation with proptosis. MATERIAL AND METHODS: A total of 37 patients with newly diagnosed GO underwent 3-T MRI scanning with iterative decomposition of water and fat (IDEAL) sequences with and without contrast enhancement. In each patient, the three largest contiguous coronal cross-sectional areas (CSA) on the EOM slices were segmented using a polygon selection tool and then summed to compute the EOM-SV. Proptosis was evaluated with the Hertel index (HI). The relationships between the HI value and EOM-SV and between HI and EOM-CSA were compared and assessed with Pearson’s correlation coefficient and the univariate regression coefficient. Inter-observer and intra-observer variability were calculated. RESULTS: HI showed a stronger correlation with EOM-SV (P < 0.001; r = 0.712, r(2 )= 0.507) than with EOM-CSA (P < 0.001; r = 0.645 and r(2 )= 0.329). The intraclass correlation coefficient indicated that the inter-observer agreement was high (0.998). The standard deviation between repeated measurements was 1.9–5.3%. CONCLUSION: IDEAL sequences allow for the measurement EOM-SV both on non-contrast and contrast-enhanced scans. EOM-SV predicts proptosis more accurately than does EOM-CSA. The measurement of EOM-SV is practical and reproducible. EOM-SV changes of 3.5–8.3% can be assumed to reflect true volume changes.