The value of diffusion-weighted imaging in children with acute central nervous system symptoms

Abstract

The value of diffusion-weighted imaging (DWI) in children with acute central nervous system (CNS) symptoms has not been fully established. We aimed to elucidate whether DWI gives additional information in children with acute CNS disorder. The subjects were eight children with acute CNS symptoms, whose cranial DWI showed signal abnormality. Two patients were suffered from cerebral infarction, and one had systemic lupus erythematosus with CNS involvement, four had acute encephalopathy, and one had relapsing encephalopathy. We retrospectively compared (1) the size of signal abnormality, (2) latency until appearance of signal abnormality, and (3) ability to differentiate old lesions between DWI and fluid-attenuation inversion recovery (FLAIR). In addition, we analyzed cerebral blood flow (CBF) changes in lesions detected by DWI, using single-photon emission computed topography (SPECT). In seven of eight patients, the size of signal abnormality was larger in DWI compared to FLAIR. In four of five patients with magnetic resonance imaging obtained during the very acute phase of CNS symptoms, the latency until appearance of signal abnormality was shorter on DWI compared to FLAIR. Combination of DWI and FLAIR successfully differentiated new lesions from old ones in all three subjects with a history of old lesions. DWI revealed signal abnormality not during the very acute phase but on 5th day of CNS symptoms in a patient with encephalopathy. In seven patients with SPECT available, lesions detected by DWI showed decreased CBF in four patients, increased CBF in two, normal CBF in one. DWI may provide useful additional information in children with acute CNS symptoms. Signal abnormalities on DWI may represent ischemic lesions or inflammatory lesions with increased or normal CBF on SPECT.