Evaluation of Blood-Brain Barrier Disruption Using Contrast-Enhanced MRI in Encephalitis

Background: Encephalitis is a potentially life-threatening inflammatory disorder of the brain parenchyma, often associated with disruption of the blood–brain barrier (BBB). Characterizing the extent and pattern of BBB breakdown provides valuable insights into disease severity, etiology, and prognosis. Contrast-enhanced magnetic resonance imaging (CE-MRI) offers a non-invasive means to assess BBB integrity through the visualization of gadolinium leakage and enhancement dynamics. The objective is to evaluate the pattern, extent, and clinical significance of BBB disruption in patients with encephalitis using CE-MRI and to correlate imaging findings with clinical presentation and disease outcome. Material and Methods: This observational study included patients with clinically and laboratory-confirmed encephalitis who underwent MRI with gadolinium-based contrast. T1-weighted post-contrast sequences were analyzed for regional enhancement, distribution pattern, and associated signal abnormalities. The degree of BBB disruption was graded semi-quantitatively and correlated with clinical features, cerebrospinal fluid (CSF) parameters, and outcome measures assessed at discharge. Results: CE-MRI revealed variable patterns of BBB disruption, ranging from focal cortical or subcortical enhancement to diffuse leptomeningeal or deep gray-matter involvement. The presence of extensive contrast enhancement correlated significantly with higher CSF protein levels and poorer neurological recovery (p < 0.05). Temporal and limbic regions were most frequently affected in viral etiologies, whereas diffuse enhancement patterns were observed in autoimmune and post-infectious cases. Conclusion: Contrast-enhanced MRI serves as a reliable, non-invasive tool for detecting BBB disruption in encephalitis. The degree and distribution of enhancement correlate with disease severity and prognosis, emphasizing the role of CE-MRI as an important adjunct in diagnosis, monitoring, and therapeutic decision-making. Keywords: Encephalitis, blood–brain barrier, contrast-enhanced MRI, gadolinium, neuroinflammation, imaging biomarkers.