2004 Fiscal Year Final Research Report Summary
Fractal analysis of neuroperfusion SPECT in patients with mild cognitive impairment.
| Project/Area Number |
15591274
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | Osaka University |
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Principal Investigator |
OKU Naohiko Osaka University, Hospital, lecturer, 医学部附属病院, 講師 (40346193)
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| Co-Investigator(Kenkyū-buntansha) |
MURASE Kenya Osaka University, Graduate School of Medicine, Professor, 医学系研究科, 教授 (50157773)
KITAGAWA Kazuo Osaka University, Graduate School of Medicine, Assistant Researcher, 医学系研究科, 助手 (70301257)
HATAZAWA Jun Osaka University, Graduate School of Medicine, Professor, 医学系研究科, 教授 (70198745)
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| Project Period (FY) |
2003 – 2004
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| Keywords | mild cognitive impairment / neuroperfusion SPECT / fractal analysis / image diagnosis / dementia / Tc-99m HMPAO / I-123 IMP |
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| Research Abstract |
On the beginning of research period, we had developed a functional 3-dimensional fractal analysis software running on a workstation. We had evaluated the regional cerebral blood flow (rCBF) SPECT in patients with vascular dementia to find that the fractal dimension (FD) was larger in vascular dementia than in normal control (i.e. heterogeneity of rCBF was high in vascular dementia). We also found that the asymmetry in FD between anterior and posterior distribution of rCBF helped one distinguishing vascular dementia from Alzheimer's disease which had almost the same global FD value. The research included 14 patients with mild cognitive impairment (MCI) and age matched 18 normal control. CBF SPECT in MCI patients showed patchy slight hypoperfusion, which was not specific for MCI. Mean FD value in MCI group was 1.071±0.194 (mean ±SD.) and was significantly higher than that (0.853 ± 0.062) in normal control group. The results suggested that the rCBF distribution in MCI patients was more heterogenous than in normal control. The sensitivity and specificity for the diagnosis of MCI by cutoff FD value =0.92 were 78% and 83%, respectively. In the next study, we tried I-123 IMP instead of Tc-99m HMPAO for neuroperfusion tracer in new series of 6 MCI patients and 6 normal control. FD values in MCI group and normal control group were 0.95±0.112 and 0.855±0.105, respectively, and there was no difference. Difference of kinetic behavior or spatial resolution between tracers might be the reason of this phenomenon. In the followup study of MCI patients who were registered to the study, 4 patients (28.6%) out of 14 had developed to Alzheimer's disease during 2 years. These converters had neither specific clinical properties such as the score of memory impairment or age nor difference in FD in the neuropefusion SPECT compared to those stayed MCI. Further investigation must be required to clarify the prognosis of MCI patients by fractal analysis.
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