Assessing regional cerebral blood flow in depression using 320-slice computed tomography

Abstract

While there is evidence that the development and course of major depressive disorder (MDD) symptomatology is associated with vascular disease, and that there are changes in energy utilization in the disorder, the extent to which cerebral blood flow is changed in this condition is not clear. This study utilized a novel imaging technique previously used in coronary and stroke patients, 320-slice Computed-Tomography (CT), to assess regional cerebral blood flow (rCBF) in those with MDD and examine the pattern of regional cerebral perfusion. Thirty nine participants with depressive symptoms (Hamilton Depression Rating Scale 24 (HAMD24) score > 20, and Self-Rating Depression Scale (SDS) score > 53) and 41 healthy volunteers were studied. For all subjects, 3 ml of venous blood was collected to assess hematological parameters. Transcranial Doppler (TCD) ultrasound was utilized to measure parameters of cerebral artery rCBFV and analyse the Pulsatility Index (PI). 16 subjects (8 = MDD; 8 = healthy) also had rCBF measured in different cerebral artery regions using 320-slice CT. Differences among groups were analyzed using ANOVA and Pearson's tests were employed in our statistical analyses. Compared with the control group, whole blood viscosity (including high\middle\low shear rate)and hematocrit (HCT) were significantly increased in the MDD group. PI values in different cerebral artery regions and parameters of rCBFV in the cerebral arteries were decreased in depressive participants, and there was a positive relationship between rCBFV and the corresponding vascular rCBF in both gray and white matter. rCBF of the left gray matter was lower than that of the right in MDD. Major depression is characterized by a wide range of CBF impairments and prominent changes in gray matter blood flow. 320-slice CT appears to be a valid and promising tool for measuring rCBF, and could thus be employed in psychiatric settings for biomarker and treatment response purposes.

Figure 1. Case example: Coronal slices from dynamic CT angiography taken from a 44-year-old woman with depression.

Circles represent regions of interest, with the mean ± SEM from 19 volume data presented. In MCA (middle cerebral artery) regions, the values of rCBF (regional cerebral blood flow) in left gray matter were lower than in the right [Left: 46.9 and 40.2 ml/(min·100 g),Right: 55.5 and 47.1 ml/(min·100 g)]. In PCA (posterior cerebral artery) regions, the values of rCBF in left gray matter were lower than in the right [Left: 30.2 ml/(min·100 g), Right: 47.8 ml/(min·100 g)].

Figure 2. The correlation between rCBFV and rCBF in cerebral artery regions.

A: A positive correlation between mean flow velocity (Vm) and rCBF in white matter (WM) of right ACA (anterior cerebral artery) (P<0.01; r = 0.874). B: A positive correlation between systolic peak velocity (Vs) and rCBF in WM of right ACA (P<0.01; r = 0.778). C: A positive correlation between Vs and rCBF in gray matter (GM) of left ACA (P<0.05; r = 0.758). D: A positive correlation between Vm and rCBF in GM of left MCA (middle cerebral artery) (P<0.05; r = 0.802). E: A positive correlation between Vm and rCBF in GM of right MCA (P<0.01; r = 0.859). rCBFV: regional cerebral blood flow velocity, rCBF: region cerebral blood flow.