[MR imaging of orbital tumors].
Nine cases of pathologically confirmed orbital tumors were evaluated with magnetic resonance imaging (MRI) at 0.5T. Seven cases were examined with orbit-coil using 7-mm-thick sections and two cases were examined with head-coil using 10-mm-thick sections. All lesions were clearly demonstrated on T1-weighted images as low intensity. However, the lesions were indistinct on T2-weighted images because of low contrast between the lesions and surrounding orbital fat and artefact produced by eye movement. Two of three cases with meningioma examined with orbit-coil were clearly discriminated from the optic nerve. Meningioma in the remaining case examined with head-coil was discriminated from the optic nerve by administration of Gd-DTPA. Adenoma of the right lacrimal gland was shown as an enlarged gland on T1-weighted images. Pseudotumors (four cases) showed very low intensity on T1-weighted images. Three cases of four pseudotumors showed low intensity on T2-weighted images. Among them one was moderately low intensity, and histological examination of the lesion showed prominent fibrotic changes. Pseudotumor of the remaining case examined with the head-coil showed same intensity with fat on T2-weighted images. Intraorbital infiltrating foci of chronic lymphocytic leukemia showed low intensity with fat on T1-weighted images, and the same intensity with fat on T2-weighted images. MRI may be useful to discriminate pseudotumor with fibrotic changes (chronic inflammatory lesions) from lymphoma or leukemic infiltration.
Irisawa
M
M
Yoshida
A
A
Mabuchi
N
N
Fujii
K
K
Yoshioka
H
H
Hamada
T
T
Ishida
O
O
D000236:Adenoma / Q000175:diagnosis; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D005350:Fibroma / Q000175:diagnosis; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008297:Male; D008579:Meningioma / Q000175:diagnosis; D008875:Middle Aged; D009918:Orbital Neoplasms / Q000175:diagnosis*