Using morphologic parameters of extraocular muscles for diagnosis and follow-up of Graves' ophthalmopathy: diameters, areas, or volumes?
OBJECTIVE
The objective of this study was to find the most appropriate, accurate, and convenient muscle parameter that can be used as a substitute for volume in monitoring the effectiveness of therapy of patients with Graves' ophthalmopathy.


METHODS
The four rectus muscles in 110 orbits (35 patients and 20 control subjects) were evaluated with MR imaging. The diameter at the largest extent of the muscle belly, as well as the long and the short diameters and the cross-sectional areas in a preselected coronal scan, were measured for each muscle and were compared with the corresponding muscle volume measured on contiguous T1-weighted transverse slices.


RESULTS
The measured coronal area correlated well with the volume of the superior (r = 0.694, p < 0.0001) and inferior (r = 0.783, p < 0.0001) recti, and the largest transverse diameter showed strong correlation with the volume of the lateral (r = 0.868, p < 0.0001) and medial (r = 0.869, p < 0.0001) recti. For the latter muscle, the coronal area also exhibited a good correlation with the volume (r = 0.838, p < 0.0001). Coronal cross-sectional areas can be well estimated by measuring both the short and long coronal muscle diameters (r values were between 0.914 and 0.966; p < 0.0001).


CONCLUSIONS
In Graves' ophthalmopathy, the volume of three of the rectus muscles can be well estimated by simple measurements on a single coronal slice, and the largest transverse diameter of the lateral rectus is suitable for the same purpose.
Szucs-Farkas
Zsolt
Z
Department of Radiology, Medical and Health Science Center, University of Debrecen, Nagyerdei krt. 98, H-4012 Debrecen, Hungary.
Toth
Judit
J
Balazs
Erzsebet
E
Galuska
Laszlo
L
Burman
Kenneth D
KD
Karanyi
Zsolt
Z
Leovey
Andras
A
Nagy
Endre V
EV
D000328:Adult; D000368:Aged; D000886:Anthropometry; D005260:Female; D006111:Graves Disease / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000473:pathology*