Regional cerebral blood flow in late-life depression: arterial spin labelling magnetic resonance study.

BACKGROUND: A limited number of studies have demonstrated changes in cerebral blood flow (CBF) in older individuals with depression, but there are considerable inconsistencies between studies. AIMS: To investigate changes in CBF using arterial spin labelling (ASL) magnetic resonance imaging (MRI) in people with late-life depression and in a similarly aged healthy control group.
METHOD: Sixty-eight participants (30 healthy individuals, 38 with depression) underwent ASL and T(1)-weighted MRI scanning. For each individual, regional estimates of separate grey and white matter CBF were obtained. Group differences in CBF and their associations with clinical features were examined.
RESULTS: Significant increases were observed in white matter CBF in patients with depression relative to the control group (F(1,65) = 9.7, P = 0.003). Grey matter CBF in lateral frontal, medial frontal, cingulate, central and parietal regions did not significantly differ between groups (F(1,65)≤2.1, P≥0.2). A significant correlation was found between white matter CBF and Montgomery-Åsberg Depression Rating Scale (MADRS) scores in depression (r' = -0.42, P = 0.03). Further analyses revealed that compared with controls, significant elevation of white matter CBF was apparent in participants whose depression was in remission (n = 21, MADRS≤10, P = 0.001) but not in those with current depression (n = 17, MADRS≥11, P = 0.80).
CONCLUSIONS: Findings suggest a compensatory response to white matter pathological change or a response to (or a predictor of) successful antidepressant treatment, perhaps by facilitating neurotransmission in specific circuits and so reducing depressive symptoms.