[Preliminary study of diffusion tensor imaging in treatment response assessment of major depression]

To assess the value of diffusion tensor imaging (DTI) in therapeutic effect evaluation of major depression.

Eighteen patients who met the CCMD-3-R criteria for major depression or bipolar disorder (with depressed episode and total score no less than 18 for 17 items of Hamilton Depression Rating Scale) and 13 aged-matched controls were examined by routine magnetic resonance imaging (MRI) and DTI. DTI were used to determine fractional anisotropy (FA) in the preselected white matter regions. All the patients with major depression received treatment with selective serotonine reuptake inhibitor (SSRI) for 6-8 weeks, and the efficacy were assessed by Hamilton Depression Scale, Hamilton Anxiety Scale (HAMA), and Clinical Global Impression (CGI) scale.

The total response rate to fluoxetine was 67%, and significant improvement was observed in 56% of the patients while 33% failed to respond after 8 weeks of treatment. The depressed subjects failing to respond to the treatment had a significant lower FA of the frontal white matter than those responding favorably to the treatment and the healthy control subjects.

DTI may identify the microstructural abnormality in the white matter, which is associated with a low remission rate of major depression.