Two-layer appearance on brain perfusion SPECT in idiopathic normal pressure hydrocephalus: a qualitative analysis by using easy Z-score imaging system, eZIS.

BACKGROUND/AIMS: It is often difficult to distinguish idiopathic normal pressure hydrocephalus (iNPH) from other neurodegenerative disorders such as Alzheimer's disease (AD). To understand the characteristic pattern of blood flow in iNPH, we performed brain perfusion SPECT and analyzed the results by using the easy Z-score imaging system (eZIS). METHODS: Subjects were 12 patients with probable iNPH and 10 probable AD patients with prominent ventriculomegaly. They underwent brain perfusion SPECT using (99m)Tc-ethylcysteinate dimer as a tracer. RESULTS: The two-tailed view display in eZIS demonstrated an obvious two-layer structure consisting of decreased blood flow around the corpus callosum and, in iNPH, enhanced perfusion in areas surrounding the cingulate gyrus in the sagittal view, while no AD cases showed these findings. CONCLUSION: Hypoperfusion around the corpus callosum in iNPH could be, at least partially, a false-positive finding due to an insufficient anatomical standardization of SPECT images caused by an abnormally enlarged ventricle. Increased blood perfusion in the external layer adjacent to the hypoperfused area might be caused by increased radioisotope count per volume resulting from exclusion of cerebral cortex by a dilated ventricle. Our results demonstrate that a two-layer appearance revealed by the two-tailed view analysis of brain perfusion SPECT using eZIS could be a means to detect iNPH.

Decreased cardiac MIBG uptake, its correlation with clinical symptoms in dementia with Lewy bodies.

Recent studies have demonstrated the usefulness of 123I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy for the diagnosis of dementia with Lewy bodies (DLB). In this study, we investigated the relationship between decreased cardiac MIBG uptake and clinical symptoms in DLB. Thirty-six patients with probable DLB and six normal controls underwent MIBG scintigraphy. We measured the early and delayed heart-to-mediastinum (H/M) ratios, and the results between subgroups based on the presence and absence of clinical symptoms were compared. The mean early and delayed H/M ratios were 1.55+/-0.29 and 1.42+/-0.30, and 30 (83.3%) and 33 (91.7%) subjects showed lower values compared to the cutoff, respectively. A statistically significant difference was found only between groups with and without orthostatic hypotension (OH). Among 10 DLB subjects without Parkinsonism, nine patients had a decreased H/M ratio in the delayed image. To our knowledge, this is the first study to correlate decreased MIBG uptake with the clinical symptoms of DLB, and to show a significantly lower H/M ratio in subjects with OH. Furthermore, we found that MIBG scintigraphy could detect cardiac sympathetic denervation regardless of clinically evident Parkinsonism. These results suggest that MIBG myocardial scintigraphy could be a valuable diagnostic test in the clinical diagnosis of DLB.

Comparison of the usefulness of brain perfusion SPECT and MIBG myocardial scintigraphy for the diagnosis of dementia with Lewy bodies.

BACKGROUND: Supportive features in the diagnostic criteria for dementia with Lewy bodies (DLB) include occipital hypoperfusion and decreased cardiac uptake of (123)I-metaiodobenzylguanidine (MIBG). In this study, we performed both brain perfusion single photon emission computed tomography (SPECT) and MIBG myocardial scintigraphy in the same subjects and evaluated their sensitivity to detect the characteristic features of DLB. METHODS: Twenty-five patients with probable DLB (76.8 +/- 5.1 years old, 10 male) underwent (99m)Tc-ethylcysteinate dimer brain perfusion SPECT and (123)I-MIBG myocardial scintigraphy. The results of SPECT were analyzed using a qualitative analysis program, easy Z score imaging system (eZIS), and an automated quantitative analysis program, 3DSRT. RESULTS: Qualitative analysis using eZIS demonstrated occipital hypoperfusion in 17 subjects (68%). The quantified mean blood perfusion in the occipital segment on the 3DSRT template was 40.7 +/- 5.03 ml/100 g/min (right) and 40.5 +/- 5.38 ml/100 g/min (left), and in 19 DLB patients these values were below the normal limit. Twenty-four of 25 subjects (96%) had decreased cardiac MIBG uptake in the delayed image. CONCLUSION: MIBG myocardial scintigraphy was superior to brain perfusion SPECT in detecting a characteristic feature of DLB. Our results suggest that combining SPECT and MIBG scintigraphy could increase the accuracy of clinical diagnosis of DLB.

Quantitative analysis of the effects of donepezil on regional cerebral blood flow in Alzheimer's disease by using an automated program, 3DSRT.

INTRODUCTION: Donepezil, an acetylcholinesterase inhibitor, has been reported to have an effect that improves cerebral blood flow (CBF) alongside its primary effect on memory function. The aim of this study was to investigate the effects of long-term, low-dose donepezil therapy on blood perfusion in Alzheimer's disease (AD) by using a fully automated regional CBF quantification program named 3DSRT. MATERIALS AND METHODS: Fifteen subjects with mild to moderate AD according to NINCDS/ADRDA criteria underwent 99mTc-ethylcysteinate dimer (ECD) brain perfusion single photon emission computed tomography (SPECT) twice with an interval of 55.1 +/- 11.0 weeks. The dose of donepezil was fixed at 5 mg/day following the induction period (3 mg/day) of 2 weeks. Clinical efficacy of donepezil was assessed by using the Mini-Mental State Examination (MMSE). The results of SPECT imaging under exactly identical conditions were analyzed by 3DSRT, which enables us to perform a very objective assessment. RESULTS: Despite a decrease of the MMSE score from 20.9 +/- 4.7 to 18.7 +/- 5.7, CBF was increased in almost all cerebral areas except the left temporal segment. The increase was statistically significant in the left callosomarginal, right central, and bilateral pericallosal and lenticular nucleus segments. CONCLUSION: Thus far, no direct cerebrovascular effects have been reported for donepezil. We hypothesize that these CBF-promoting effects of donepezil might be related to increased neuronal activity and enhanced connection of neurons.

Usefulness of a blood flow analyzing program 3DSRT to detect occipital hypoperfusion in dementia with Lewy bodies.

In the latest criteria for the clinical diagnosis of dementia with Lewy bodies (DLB), supportive features include generalized low uptake on SPECT/PET perfusion scan with reduced occipital activity. In this study, we investigated the usefulness of a cerebral blood flow (CBF) quantification program '3DSRT' in detecting occipital hypoperfusion in DLB. Twenty two patients with probable DLB, 38 patients with probable Alzheimer's disease (AD) and 16 normal controls underwent brain perfusion SPECT. Compared with AD, DLB patients had a bilateral lower CBF in the posterior cerebral segments. The correlation of clinical symptoms and brain blood perfusion was examined by dividing the subjects into subgroups. DLB patients with Parkinsonism, when compared to non-Parkinsonism subgroup, had a lower CBF throughout the cerebrum with statistical significance in the posterior cerebral segments. The quantitative analysis of brain perfusion SPECT by 3DSRT could be a useful supportive measurement in the diagnosis of DLB.

Quantitative analysis of brain perfusion SPECT in Alzheimer's disease using a fully automated regional cerebral blood flow quantification software, 3DSRT.

PURPOSE: The clinical symptoms of Alzheimer's disease (AD) show great diversity depending on the clinical stage. We investigated the correlation of regional cerebral blood flow (rCBF) changes and the clinical severity of AD patients. METHODS: Thirty-nine AD patients and 16 normal subjects participated in this study. AD patients were divided into three subgroups by clinical severity. Quantitative brain perfusion SPECT analyses were performed using a rCBF quantification software, 3DSRT. RESULTS: In mild AD, significant decreases of rCBF were detected in the bilateral parietal, angular gyrus, pericallosal, thalamus, right temporal and left hippocampal regions. Moderate AD patients showed significantly lower blood flow than those with mild AD only to the right hippocampus. Analysis of the severe AD group revealed a nearly diffuse decrease of rCBF throughout the cerebral cortex except for part of the frontal lobe compared with moderate patients. CONCLUSIONS: These results were consistent with previous findings demonstrated by qualitative analysis of CBF. The decreased thalamic blood flow was noteworthy as this finding has rarely been reported. In consideration of the structure and function of the Papez circuit, which connects the medial temporal lobe and thalamus, a remote metabolic effect might be the cause of lower rCBF in the thalamus.