Assessment of therapeutic response in patients with brain abscess using diffusion tensor imaging

Accurate assessment of therapeutic response in patients with brain abscess (BA) is essential to direct appropriate therapy. This study was performed with an aim to see the treatment-induced changes in diffusion tensor imaging (DTI) indices (i.e., fractional anisotropy [FA] and mean diffusivity [MD]) in follow-up patients with BA after treatment.

Twenty patients with BA were prospectively studied in this study. Diffusion tensor imaging in first follow-up was done in all after 1 week and in 6 at 4 weeks of the initial study.

The mean FA and MD values in first, second, and third studies were 0.28 +/- 0.03 and (0.81 +/- 0.07) x 10(-3) mm(2)/s, 0.18 +/- 0.09 and (1.08 +/- 0.09) x 10(-3) mm(2)/s, and 0.13 +/- 0.04 and (0.99 +/- 0.13) x 10(-3) mm(2)/s, respectively. The FA value was significantly (P < .01) decreased along with no significant change in MD value (P = .08) for 3 study periods. The mean volume (in milliliter) of the abscesses was 2.14 +/- 1.04, 1.34 +/- 0.45, and 0.77 +/- 0.14 in first, second, and third studies, respectively.

We conclude that the reduction in FA value reflects the down-regulation of the neuroinflammatory molecules in response to treatment in patient with BA and may be used to assess therapeutic response in these patients in future.