The apparent diffusion coefficient (ADC) as a potential marker of inflammation associated with body abscesses

Objective: To assess the feasibility of apparent diffusion coefficient analysis in evaluating the inflammatory severity of extracranial abscesses. Methods: This retrospective study included 23 patients with solitary body abscesses (except those in the brain) who underwent 1.5-T diffusion-weighted magnetic resonance imaging (DWI) at b-values of 0 and 1000 s/mm². Three types of the Apparent Diffusion Coefficient (ADC) measurements of abscesses were performed: the mean ADC value in region of interest (ROI), volume of interest (VOI), and histogram analysis of the ADC distribution in the VOI. Furthermore, two different areas were used: high-intensity area on b = 0 and b = 1000 s/mm² images. Subsequently, correlations between ADC data and C-reactive protein (CRP) levels were assessed using Pearson’s correlation coefficient (R) analyses. Results: The strongest correlation was observed between the mean ADC value in VOI and CRP level (R = 0.78, P <0.01), followed by ROI (R = 0.77, P <0.01) by using the high-intensity area on the b = 0 s/mm² images. Conclusion: The mean ADC value in the ROI encompassing the abscess at a b-value of 0 s/mm² may be useful to assess the inflammatory activity of an abscess in daily practice.