Frontiers in Psychiatry (Mar 2013)

Prediction of selective serotonin reuptake inhibitor response using diffusion-weighted MRI

  • Christine eDelorenzo,
  • Christine eDelorenzo,
  • Lauren eDelaparte,
  • Binod eThapa-Chhetry,
  • Jeffrey eMiller,
  • John eMann,
  • Ramin V Parsey

DOI
https://doi.org/10.3389/fpsyt.2013.00005
Journal volume & issue
Vol. 4

Abstract

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Pretreatment differences in serotonergic binding between those who remit to antidepressant treatment and those who do not have been found using Positron Emission Tomography (PET). To investigate these differences, an exploratory study was performed using a second imaging modality, diffusion-weighted MRI (DW-MRI). Eighteen antidepressant-free subjects with Major Depressive Disorder received a 25-direction DW-MRI scan prior to eight weeks of selective serotonin reuptake inhibitor (SSRI) treatment. Probabilistic tractography was performed between the midbrain/raphe and two target regions implicated in depression pathophysiology (amygdala and hippocampus). Average fractional anisotropy (FA) within the derived tracts was compared between SSRI remitters and nonremitters, and correlation between pre-treatment FA values and SSRI treatment outcome was assessed. Results indicate that average FA in DW-MRI-derived tracts to the right amygdala was significantly lower in nonremitters (0.55±0.04) than remitters (0.61±0.04, p<0.01). In addition, there was a significant correlation between average FA in tracts to the right amygdala and SSRI treatment response. These relationships were found at a trend level when using the left amygdala as a tractography target. No significant differences were observed when using the hippocampus as target. These regional differences, consistent with previous PET findings, suggest that the integrity and/or number of white matter fibers terminating in the right amygdala may be compromised in SSRI nonremitters. Further, this study points to the benefits of multimodality imaging and suggests that DW-MRI may provide a pretreatment signature of SSRI depression remission at eight weeks.

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