Computed diffusion-weighted imaging for acute pediatric encephalitis/encephalopathy

Abstract

Background

Computed diffusion-weighted imaging (DWI) (cDWI) is a computational technique that can be used to calculate a high b-value image from DWI acquired with at least two different lower b-values.

Purpose

To explore the utility of cDWI for the diagnosis of acute pediatric encephalitis/encephalopathy.

Material and Methods

Twenty-two children were enrolled, for whom acquired DWI (aDWI) with b = 1000 and 3000 was examined during the acute phase of febrile encephalitis/encephalopathy. For each patient, cDWI was calculated pixel by pixel from aDWI b = 0 and 1000 images by using software equipped with a commercially available image viewer. Quantitative assessment was performed by calculating a signal intensity (SI) ratio, defined as the mean SI of the affected lesion/the mean SI at the center of the pons for each image. The Mann–Whitney test was used for statistical analysis of the SI ratios of cDWI b = 3000 versus aDWI b = 1000 and cDWI b = 3000 versus aDWI b = 3000. A P value < 0.05 was considered statistically significant.

Results

The SI ratio of cDWI b = 3000 images was significantly higher than that of aDWI b = 1000 images (P = 0.0391), whereas the SI ratio of cDWI b = 3000 images was not significantly different from that of aDWI b = 3000 images (P = 0.991).

Conclusion

cDWI b = 3000 is useful for detecting diffusion-restricted lesions in acute pediatric encephalitis/encephalopathy compared to aDWI b = 1000 and 3000. cDWI enables the generation of high b-value images without additional scanning, which will be helpful for sedated pediatric patients in clinical settings.