Background
In our previous study, a vascular dementia (VaD) due to small-vessel disease showed more heterogeneous cerebral blood flow distribution than healthy controls. 1 In the present study, we investigated whether or not regional cerebral blood flow (rCBF) in patients with VaD due to small-vessel disease is locally reduced in particular brain areas compared with normal healthy controls.
Subjects and method
The subjects consisted of 17 right handed patients with VaD due to small-vessel disease (age(y): 69. 5 ± 8.5, MMSE: 18.6 ± 4.5) (VaD group) and 20 healthy volunteers (age(y): 62.9 ± 11.3, MMSE: 26.5 ± 2.6) (control group). The diagnosis of VaD due to small-vessel disease was made on the basis of the NINDS–AIREN criteria 2 and a full clinical examination including history, neuropsychological tests, neurological examination, and brain MRI. The SPECT was performed with 99mTc-hexamethyl-propyleneamine oxime. The images were reconstructed without a correction for tracer-washout. The SPM99 was employed for the analysis. In the SPM99, a threshold masking value was set to be 0.6 for the control and VaD group.
Results
In the VaD group, rCBF of right thalamus and left parietal cortex was significantly lower than that in normal group (p < 0. 05, uncorrected).
Discussion
Thalamus has a projection pathway to association area of cerebral cortices responsible to higher cognitive functions. 3 Left parietal cortex is also one of such areas. The present results suggested a possibility that impairment of cognition / higher neurological functions in patients with VaD due to small vessel disease is partly caused by dysfunction of thalamus and parietal cortex.