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 CBE in lateral frontal, medial frontal, cingulate, central and parietal regions did not significantly differ between groups (F-1,F-65 <= 2.1, P >= 0.2). A significant correlation was found between white matter CBF and Montgomery-Asberg 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.