Diffusion Weighted MRI Patterns in Viral Encephalitis and Their Correlation with Clinical Outcomes

Abstract

Objectives: To study the DW-MRI pattern in patients with viral encephalitis and to assess its association with clinical outcome.

Methods: It is a descriptive cross sectional study, where the study setting was in the department of radiology at Liaqat National hospital and medical college Karachi from 23 February 2025 till 23 November 2025. The patients with viral encephalitis were selected by consecutive non probability sampling and a total of 89 patients were included with clinically suspected and radiologically confirmed viral encephalitis. The pattern of lesions and their anatomical distribution were used to classify DW-MRI findings. The clinical outcomes were evaluated as complete or incomplete or no recovery. Data was analyzed using a statistical package for social sciences (SPSS) version 26, and a p value of < 0.05 was set as the threshold for significance.

Results: The mean age of the patients was 34.6 ± 11.3 years and 58.4% were males. The pattern of bilateral cerebral involvement occurred in 38.2% of patients and was the most common pattern of DWI involvement. In 57.3% of cases, there was involvement of the temporal lobes. 68.5% of patients made a full neurological recovery. Diffuse cerebral involvement had the worst clinical outcome and there was a significant relationship between diffusion weighted imaging patterns and clinical outcome (p < 0.001).

Conclusion: There was a significant relationship between DW-MRI patterns and neurological outcomes in viral encephalitis. The presence of extensive and diffuse diffusion restriction was correlated with poor prognosis and with the presence of neurological deficits.