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Published on: November 6, 2017
Statistical image analysis of cerebral blood flow in vascular dementia with small-vessel disease
Takuya Yoshikawa1, Kenya Murase, Naohiko Oku
1Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine (A8), 2-2 Yamadaoka, Suita City, Osaka 565-0871, Japan. yoshi@tracer.med.osaka-u.ac.jp
Insights
Vascular dementia (VaD) patients exhibit altered cerebral blood flow (CBF) heterogeneity, measurable with 3D fractal analysis (3D-FA) and 3D stereotactic surface projections (3D-SSP) via CBF SPECT imaging.
Area of Science:
- Neuroimaging
- Vascular Neurology
- Radiology
Background:
- Small-vessel disease is the most common cause of vascular dementia (VaD).
- Diagnosing VaD is challenging due to subtle or absent focal abnormalities in cerebral blood flow (CBF).
- Objective evaluation of CBF distribution is crucial for accurate VaD diagnosis.
Purpose of the Study:
- To assess the clinical validity of combining CBF SPECT with 3D fractal analysis (3D-FA) and 3D stereotactic surface projections (3D-SSP) for diagnosing VaD.
- To quantitatively evaluate the heterogeneity of CBF distribution in VaD patients.
- To identify patterns of CBF reduction in VaD.
Main Methods:
- Subjects included 17 VaD patients and 20 healthy controls.
- Cerebral blood flow SPECT was performed using (99m)Tc-hexamethylpropyleneamine oxime.
- Image processing involved 3D-FA to calculate fractal dimension (FD) and 3D-SSP to analyze CBF distribution patterns.
Main Results:
- Mean FD values were significantly higher in the VaD group (1.093 ± 0.153) compared to the control group (0.853 ± 0.062) (P < 0.0001).
- 3D-SSP revealed two abnormal CBF patterns in VaD: global reduction across the cerebral cortex and reduction predominantly in the frontal region.
- These findings indicate increased CBF heterogeneity in VaD.
Conclusions:
- CBF SPECT combined with 3D-FA and 3D-SSP offers a simple and objective method for evaluating CBF in VaD.
- The techniques successfully identified differences in CBF heterogeneity and revealed distinct patterns of reduced blood flow.
- These imaging analysis techniques show promise for detailed examination and diagnosis of VaD.
Unlabelled:
Small-vessel disease with dementia, which is the most frequent type of vascular dementia (VaD), often shows a cerebral blood flow (CBF) distribution with no obvious focal abnormalities and is therefore difficult to evaluate objectively. In this study, we combined CBF SPECT with 3-dimensional fractal analysis (3D-FA) to quantitatively assess the heterogeneity of CBF distribution and with 3-dimensional stereotactic surface projections (3D-SSP) to evaluate the distribution of CBF. We then evaluated the clinical validity of these techniques for the imaging diagnosis of VaD.
Methods:
The subjects consisted of 17 patients who were diagnosed as having VaD due to small-vessel disease (VaD group) on the basis of a full clinical examination, including history, neuropsychologic tests, neurologic examination, and neuroimaging methods, and 20 healthy volunteers (control group). CBF SPECT was performed with (99m)Tc-hexamethylpropyleneamine oxime, and the reconstructed images were subjected to image processing by 3D-FA and 3D-SSP. Based on the results, the fractal dimension (FD) was compared between the VaD and control groups, and the distribution pattern of CBF was examined in the VaD group.
Results:
The mean FD values in the VaD group and the control group were 1.093 +/- 0.153 and 0.853 +/- 0.062 (mean +/- SD), respectively. The mean FD value in the VaD group was significantly higher than that in the control group (P < 0.0001). 3D-SSP analysis in the VaD group showed that there were 2 abnormal patterns: One was globally reduced blood flow in the whole cerebral cortex, and the other was a reduction mainly confined to the frontal region.
Conclusion:
CBF SPECT images showed higher mean FD values in the VaD group than in the control group, suggesting a difference in the heterogeneity of CBF. Image processing with 3D-SSP successfully revealed that reduced cortical blood flow could be divided into 2 patterns. Because image analysis techniques, such as 3D-FA and 3D-SSP, allowed the simple and objective evaluation of CBF in patients with VaD, these methods seem to be useful for detailed examination of the blood flow pattern detected by CBF SPECT in patients with VaD.
