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Orbital involvement in Wegener granulomatosis: MR findings in 12 patients
N A Courcoutsakis1, C A Langford, M C Sneller
1Diagnostic Radiology Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
Purpose:
Our goal was to characterize the MR features of orbital Wegener granulomatosis (WG).
Method:
Twelve patients with pathologically proven WG were studied with MRI. Enhanced and unenhanced T1-weighted sequences with conventional and fat-suppressed techniques were used. T2-weighted images were also obtained. Signal intensity measurements were made in each orbital lesion on the T2-weighted images and compared with that of normal fat. The degree of enhancement was also evaluated by measuring the change in signal intensity of each lesion between the unenhanced and enhanced studies.
Results:
Seventeen orbital lesions were identified in the 12 patients. Fifteen of the lesions examined by T2-weighted sequences demonstrated a marked decrease in signal intensity. The unenhanced, non-fat-suppressed T1-weighted sequences provided the best contrast between lesion and normal structures. All of the WG lesions enhanced, but the degree of enhancement varied. The enhancement characteristics were best appreciated on the fat-suppressed T1-weighted technique.
Conclusion:
MRI is an excellent imaging modality to evaluate orbital involvement in WG. A marked decrease in the T2 signal is a characteristic feature of this entity. The unenhanced, non-fat-suppressed T1-weighted sequence is the preferred method for lesion detection and for definition of the pattern of anatomic involvement when utilizing MRI.
Insights
Magnetic resonance imaging (MRI) effectively characterizes orbital Wegener granulomatosis (WG). A significant decrease in T2 signal intensity is a key MRI finding for diagnosing this condition.
Area of Science:
- Radiology
- Ophthalmology
- Immunology
Background:
- Wegener granulomatosis (WG) is a rare autoimmune vasculitis that can affect orbital structures.
- Accurate diagnosis of orbital WG is crucial for timely treatment and preventing vision loss.
Purpose of the Study:
- To characterize the magnetic resonance (MR) imaging features of orbital Wegener granulomatosis (WG).
Main Methods:
- Retrospective review of MRI scans from 12 patients with pathologically confirmed WG.
- Utilized enhanced and unenhanced T1-weighted sequences (conventional and fat-suppressed) and T2-weighted images.
- Analyzed signal intensity and enhancement patterns of 17 orbital lesions.
Main Results:
- Fifteen of 17 lesions showed a marked decrease in signal intensity on T2-weighted images.
- Unenhanced, non-fat-suppressed T1-weighted sequences offered optimal contrast for lesion detection.
- All WG lesions demonstrated enhancement, with fat-suppressed T1-weighted sequences best visualizing enhancement characteristics.
Conclusions:
- MRI is an excellent modality for evaluating orbital WG.
- A marked decrease in T2 signal intensity is a characteristic feature of orbital WG on MRI.
- Unenhanced, non-fat-suppressed T1-weighted sequences are preferred for lesion detection and defining anatomical involvement.