Echo-Planar MR Sequences in the Diagnosis of Intracranial Infectious Diseases

Abstract

To assess the value of echo-planar-imaging (EPI) MR sequences in the diagnosis of intracranial infectious diseases, we reviewed single-shot EPI MR images obtained in 20 patients comparing them with conventional spin-echo (SE) or fluid attenuated inversion-recovery (FLAIR) images. Their diagnosis included meningitis, encephalitis or meningoencephalitis, brain abscess, epidural empyema, and Creutzfeldt-Jakob disease. We obtained EPI-T2-weighted images (T1WIs) in eight patients, EPI-FLAIR images in 13, and EPI-diffusion-weighted images (DWIs) in 17. Mainly due to the patient's motion, EPI-T2WIs were better than SE-T2WIs in three of the eight patients and EPI-FLAIR images were better than conventional FLAIR images in three of the 13 patients. In the remaining patients, EPI-T2WIs and EPI-FLAIR images were equivalent or inferior to conventional images. In six patients with encephalitis or meningoencephalitis, their lesions of encephalitis showed apparent hyperintensity on EPI-DWIs. In four patients, EPI-DWIs also demonstrated hyperintensity of the contents of abscess or empyema most conspicuously among images obtained. The value of EPI-T2WIs and EPI-FLAIR images is considered to be limited in uncooperative patients. However, EPI-DWIs could provide valuable information in some diseases.