Abstract
BACKGROUND AND PURPOSE: DWI by using higher b-values provides tissue diffusivity with less T2 shinethrough effect. VCD in the abscess cavity correlates with ADC values. The purpose of this study was to investigate which b-value−derived ADC correlates better with VCD.
MATERIALS AND METHODS: Thirty patients with brain abscess underwent conventional MR imaging and DWI with b = 1000, 2000, and 3000 s/mm2 on a 3T MR imaging scanner. ADC values were quantified by placing regions of interest inside the abscess cavity in all sections where the lesion was apparent on coregistered ADC maps derived from different b-values. VCD was measured on pus aspirated.
RESULTS: An increase in b-value was associated with a decrease in ADC values in normal parenchyma as well as in the abscess cavity. The most significant negative correlation of VCD was observed with b = 3000 s/mm2 (r = −0.98, P = .01).
CONCLUSIONS: VCD in the abscess cavity can be best assessed at b = 3000 s/mm2 secondary to the reduction in the T2 shinethrough effect. DWI with b = 3000 s/mm2 is of promising value in the assessment of the therapeutic response of brain abscess.
ABBREVIATIONS
- ADC
- apparent diffusion coefficient
- CNWM
- contralateral normal white matter
- DWI
- diffusion-weighted imaging
- FLAIR
- fluid-attenuated inversion recovery
- FWM
- frontal white matter
- GM
- gray matter
- spp
- species
- VCD
- viable cell density
- WM
- white matter
- © 2011 by American Journal of Neuroradiology
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