Other / Other / MRI

Uveitis

Evaluation of uveal tract inflammation in patients presenting with eye pain, photophobia, and reduced visual acuity, with urgent need to characterize location and etiology to guide treatment. The Three Anatomical Parts of the Uvea Iris: The colored, donut-shaped ring at the front of the eye that controls how much light enters through the pupil. Ciliary Body: A thick ring of tissue behind the iris that holds the eye's lens in place and makes the fluid (aqueous humor) inside the eye. Choroid: A membrane filled with tiny blood vessels that lines the back of the eye, sandwiched between the sclera and the retina, providing oxygen and nourishment

Key Images

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Look For First
  • Thickening and enhancement of the uveal tract on T1 post-contrast MRI
  • Abnormal hyperintense signal on FLAIR sequence suggesting altered vitreous signal
  • Anatomical location of inflammation (anterior vs. intermediate vs. posterior vs. panuveitis) to guide differential diagnosis
Key Image Findings
  • MRI is the modality of choice for imaging uveitis. The T1 sequences demonstrate thickening of the affected uveal tract with possible altered vitreous signal.
  • T2 weighted imaging shows thickening of the affected uveal tract and may reveal retinal detachment or subretinal effusions indicative of more extensive inflammation.
  • FLAIR sequences are very sensitive for detecting altered vitreous signal, appearing as hyperintense signal in areas of inflammation.
  • T1 post-contrast imaging shows marked enhancement of the affected uveal tract, typically appearing smooth but occasionally nodular; comparison to the unaffected side is essential in unilateral cases, and nodular enhancement requires careful assessment to exclude neoplasm.
  • DWI/ADC sequences typically do not show abnormal restricted diffusion in uncomplicated uveitis, but occasionally may demonstrate restricted diffusion of the uvea and subretinal effusions.
  • CT is less sensitive than MRI and may show uveoscleral thickening and enhancement but is not the imaging modality of choice for uveitis evaluation.
  • Anterior uveitis typically affects the iris and anterior chamber, suggesting idiopathic or non-infectious inflammatory etiologies such as sarcoidosis.
  • Posterior uveitis affecting the choroid typically correlates with infectious etiologies (toxoplasmosis, tuberculosis) or non-infectious systemic inflammatory disease.
Differential Diagnosis
  • Scleritis: inflammation of the sclera with different anatomical location; may coexist with uveitis but represents distinct pathology.
  • Endophthalmitis: acute bacterial or fungal infection of the vitreous and uveal tract presenting clinically similar but typically more acute in presentation with severe pain and vision loss.
  • Panophthalmitis: inflammation extending beyond the uveal tract to involve the entire globe, representing more severe or fulminant disease.
  • Posterior scleritis: may mimic posterior uveitis but the inflammation is localized to the sclera rather than the uveal tract.
  • Choroid neoplasm: nodular enhancement of the choroid can mimic nodular uveitis but nodular uveitis is uncommon and requires careful distinction from tumors.
  • Acute retinal necrosis: viral inflammation of the retina may present with uveitis but typically shows more extensive retinal involvement and whitening on ophthalmoscopy.
Discussion

Anatomical localization of uveitis on imaging correlates strongly with etiology: anterior uveitis suggests idiopathic or non-infectious inflammatory disease, intermediate uveitis may be idiopathic or associated with multiple sclerosis, posterior uveitis typically indicates infectious causes or systemic inflammatory disease, and panuveitis suggests sarcoidosis, Lyme disease, tuberculosis, or syphilis.

Associated systemic conditions include ankylosing spondylitis, ulcerative colitis, rheumatoid arthritis, sarcoidosis, Behçet disease, Vogt-Koyanagi-Harada disease, and rarely Blau syndrome or Kikuchi-Fujimoto disease, highlighting the importance of systemic workup.

Non-infectious inflammatory uveitis is treated with corticosteroids (topical, intraocular, or intravenous) with immunosuppression reserved for severe or refractory cases.

Infectious uveitis requires etiology-specific antimicrobial therapy including antibiotics, antivirals, or antifungals depending on the causative agent.

Early detection and appropriate treatment are critical for preserving vision, making rapid imaging assessment and diagnosis essential.

Enhancement patterns on contrast-enhanced T1 MRI should be smooth in typical cases; nodular enhancement is uncommon and warrants careful assessment to exclude neoplastic etiologies.

Reporting Pearls

Report the specific anatomical location of uveitis (anterior, intermediate, posterior, or panuveitis), document the degree of uveal tract thickening and the intensity/pattern of enhancement on contrast-enhanced T1 imaging, note the presence of any subretinal effusions or retinal detachment on T2 imaging, and explicitly compare the affected side to the unaffected side in unilateral cases to emphasize the inflammatory changes.

Pitfalls
  • Failure to specifically localize the inflammation to the anatomically relevant portion of the uveal tract may result in missed etiological clues and incorrect differential diagnosis.
  • Mistaking nodular uveal enhancement for choroidal neoplasm; nodular uveitis is uncommon and requires careful clinical-radiological correlation and possibly follow-up imaging to exclude malignancy.
  • Overlooking subretinal effusions or retinal detachment on T2 imaging, which may indicate more extensive or severe inflammation affecting prognosis and treatment planning.
  • Not recognizing that DWI/ADC sequences typically do not show restricted diffusion in uncomplicated uveitis; the presence of significant restricted diffusion should prompt consideration of infectious etiologies or complications such as abscess formation.
Source: Reference source