[Correlation of the cognitive function and the duration of the illness with the regional cerebral blood flow in the patients with Parkinson's disease: objective evaluation using stereotactic extraction estimation analysis in 123I-IMP SPECT].

OBJECTIVE

To investigate the correlation of the cognitive function and the duration of the illness with the regional cerebral blood flow (rCBF) in patients with Parkinson's disease (PD), by means of an objective diagnostic index of brain imaging, stereotactic extraction estimation (SEE) of 123I-IMP SPECT.

PATIENTS AND METHODS

We examined 123I-IMP SPECT in 24 patients with PD (age = 71.79 +/- 5.18 years; the Mini-Mental State Examination: MMSE score = 21.46 +/- 7.62 points; the duration of the illness = 6.63 +/- 3.91 years; Yahr scale = 3.29 +/- 0.74). A contrast database was created by averaging extracted database sets of the contrast group (numbers = 14 cases; age = 74.64 +/- 5.99 years, the MMSE score > or = 29 points). We applied SEE for Z-score images of three-dimensional stereotactic surface projection analysis (3D-SSP) for 123I-IMP SPECT, and calculated Zextent ratio by taking advantage of severity of Z-score (the mean value) with extent ratio (%) in the frontal, occipital, temporal, parietal and posterior cingulate cortices, and precuneus, respectively. We investigated the correlation coefficient between the MMSE score and Zextent ratio, and between the duration of the illness and Zextent ratio in the six regions. In addition, we compared Zextent ratio in the six regions between the non-demented group (numbers = 12 patients; MMSE > or = 24 points) and the demented group (numbers =12 patients; E score < or = 23 points).

RESULTS

There were negative correlations between the MMSE score and Zextent ratio in the temporal (p < 0.05) and posterior cingulate cortices (p < 0.05), and positive correlations between the duration of the illness and Zextent ratio in the frontal (p < 0.01), temporal (p < 0.01), parietal (p < 0.05) and posterior cingulate cortices (p < 0.01). Z*extent ratio was significantly high only in the posterior cingulate cortex(p < 0.05) in the demented group.

CONCLUSIONS

SEE for Z-score images of 3D-SSP revealed a close relationship between the decline of the MMSE score and the duration of the illness, and the perfusion reduction of the posterior cingulate cortex in patients with PD. These findings suggest that the perfusion reduction of the posterior cingulate cortex reflects the decline of cognitive impairment of patients with PD.