Imaging studies helpful in diagnosis of uveitis

Chest and joint radiographs, CT, MRI, and other extraocular imaging modalities must be tailored to each patient and not ordered routinely.

Cleveland-Most forms of infectious uveitis, such as toxoplasmosis, toxocariasis, necrotizing herpetic retinitis, and cytomegalovirus (CMV) retinitis, can be diagnosed without ocular imaging studies. In these instances, the diagnosis can be made based upon their typical clinical appearance and confirmed by serology and polymerase chain reaction (PCR).

However, tests such as intravenous fluorescein angiography (IVFA), indocyanine green (ICG) angiography, optical coherence tomography (OCT), and B-scan ultrasound are helpful in the diagnosis and in the evaluation of complications of entities, such as white dot syndromes, pars planitis, intraocular lymphoma, sarcoidosis, and several others, according to Careen Yen Lowder, MD, PhD, professor of ophthalmology at the Cleveland Clinic Cole Eye Institute, here.

IVFA is particularly important in diagnosing the white dot syndromes and distinguishing between them because the prognoses and treatment-or lack of treatment-are very different, Dr. Lowder said. In addition, ICG angiography is important in diagnosing the active leading edges of serpiginous choroidopathy and lesions that can be found in birdshot retinochoroidopathy and in multiple evanescent white dot syndrome (MEWDS).

She added that chest radiograph, sinus imaging, and computed tomography (CT) are helpful in Wegener's granulomatosis, and abdominal angiography will be helpful in the diagnosis of polyarteritis nodosa.

However, most intermediate and panuveitis syndromes can be diagnosed without imaging studies, nor are these studies helpful in Lyme disease, sympathetic ophthalmia, or syphilitic uveitis.

Fluorescein angiography is helpful, though, in diagnosing Vogt-Koyanagi-Harada syndrome; it will reveal the pinpoint type of fluorescent spots that underlie the serous retinal detachment. Another imaging test, B-scan ultrasound, will be helpful in revealing choroidal thickening.

"If you have a patient who presents with significant peripheral vascular sheathing, which is overlaid by vitreous debris, you may want to perform MRI of the brain to detect multiple sclerosis," Dr. Lowder said. "And if you suspect primary intraocular lymphoma, you would want to obtain MRI of the brain to rule out CNS lymphoma."

Sarcoidosis is a multisystem disease with granulomatous inflammation, and patients may have chronic anterior, intermediate, or diffuse uveitis. According to Dr. Lowder, certain imaging tests can help the clinician narrow the diagnosis. A chest radiograph may be ordered initially, followed by chest CT if the plain radiograph is normal. Chest CT can reveal mediastinal lymphadenopathy that is not visible on a plain radiographs. IVFA may reveal perivenular, retinal, and choroidal granulomas with early hyperfluorescence and late staining, macular edema, and optic disc edema. OCT can confirm macular edema, while an MRI of the brain may also be helpful. If posterior scleritis is suspected, B-scan ultrasound can be ordered.

Several tests are also recommended for patients with immune recovery uveitis, Dr. Lowder said. Patients with AIDS and healed CMV retinitis may develop intraocular inflammation with cystoid macular edema (CME), epiretinal membrane, and disc edema. In such cases, IVFA demonstrates increased vascular permeability and CME, while OCT confirms CME.

In cases of suspected HLA-B27-associated uveitis, chronic iridocyclitis, and juvenile idiopathic arthritis, OCT will confirm the presence of CME. Ultrasound biomicroscopy of the ciliary processes may reveal atrophy and cyclitic membranes. Sacroiliac and affected joint radiographs may also be obtained.

Dr. Lowder stressed that chest and joint radiographs, CT, MRI, and other extraocular imaging modalities must be tailored to each patient and not ordered routinely.