Diffusion-weighted images in children with meningoencephalitis

Abstract

Purpose: The objective of the study was to evaluate the maps of apparent diffusion coefficients (ADCs) and diffusion-weighted (DW) images in demonstrating meningoencephalitic lesions in children. Materials and methods: Between May 1998 and May 2000, 18 infants and children (4.5–190 months old) suffering from meningoencephalitis were included in the study. The diagnoses were bacterial meningoencephalitis in 8 and aseptic or viral in 10 patients. All 18 patients had brain MRI examinations. In the axial plane, three pulse sequences were performed on all patients: (1) FSE T2W images; (2) fast FLAIR images; (3) single-shot echoplanar DW images were acquired. Another 18 patients from the control group also received DW image examination. ADCs were computed for all regions on each DW image. Results: The absolute values of CNRs of lesions on T2W (7.27±5.51), FLAIR (5.56±5.03) and DW (13.36±16.64) images were significantly greater than those on ADC maps (0.42±0.30) in the study group of patients ( P<.01). In addition, absolute CNRs on DW images were significantly greater than on T2W and FLAIR images ( P<.01). However, lesions on ADC maps in the study group have significantly greater CNRs than in the control group (0.13±0.12) ( P<.01). CNRs on initial DW images from patients with atrophy or swelling of meningoencephalitic lesions were significantly different from the CNRs of those patients without significant changes in meningoencephalitic lesions ( P=.02<.05). Conclusion: The DW image is a sensitive tool for detecting meningoencephalitic lesions and is better than FSE T2W and fast FLAIR images in CNRs. Diffusion MR techniques provides new ways to possibly predict the outcome of intracranial infectious diseases in children.