Comparison of magnetic resonance imaging, clinical, and laboratory findings in atypical and typical posterior reversible encephalopathy syndrome

Purpose: The aim of the study is to compare cases defined as typical and atypical Posterior Reversible Encephalopathy Syndrome (PRES) based on the regions of involvement and imaging features in terms of clinical findings and laboratory values. Materials and Methods: The study included 79 patients who were evaluated as PRES according to imaging and clinical findings between January 2012 and March 2022, had sufficient clinical and laboratory data, and had optimal magnetic resonance (MR) images. Thirty-two of the patients were male, 47 were female, and 61 patients were in the pediatric age group. All patients had non-contrast FLAIR, T1 and T2-weighted images, 24 patients had diffusion-weighted images, and 43 patients had contrast-enhanced T1-weighted images. Patients were divided into typical and atypical groups according to MR imaging findings. Each group was compared independently according to clinical and laboratory data. Results: Hemorrhage was detected in 2, diffusion restriction in 16, enhancement in 13, and lesions located in deep white and gray matter in 10 patients. According to the areas of involvement, parietooccipital was detected in 11 patients, posterior frontotemporal in 28 patients, cerebellar in 29 patients, brainstem in 5 patients, and thalamus in 6 patients. According to the localization, while the change in consciousness was observed in 41% of the typical group, this was more in the atypical group (72%). In addition, inorganic phosphorus and potassium values were lower in the atypical group. Change in consciousness was detected more in patients with enhancement compared to patients without enhancement. Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) values were significantly higher in the atypical group. No significant difference was detected in other data. Conclusion: Atypical localization and MR imaging features in PRES cases may lead to potential diagnostic difficulties and traps for radiologists evaluating these scans in emergency situations. In addition, some clinical and laboratory findings may be worse in atypical cases, and early and correct diagnosis is very important for treatment management.