Brain Perfusion Single-Photon Emission Computed Tomography Using an Easy Z-Score Imaging System Predicts Progression to Neurodegenerative Dementia in Rapid Eye Movement Sleep Behavior Disorder

INTRODUCTION

Longitudinal studies have reported that patients with idiopathic rapid eye movement sleep behavior disorder (IRBD) have an increased risk of developing synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies (DLB). Clinical trials of disease-modifying therapies for IRBD patients require suitable biomarkers that can predict the short-term onset of neurodegenerative dementia.

METHODS

We retrospectively examined if easy Z-score imaging system-specific volume-of-interest analysis (SVA) using brain perfusion single-photon emission computed tomography (SPECT) imaging or the cingulate island sign score can predict the short-term development of neurodegenerative dementia in 30 patients with IRBD.

RESULTS

Ten patients (33.3%) who exceeded the thresholds for three indicators (severity, extent, and ratio) were included in an SVA-positive group, while 20 (66.7%) were included in an SVA-negative group. Nine (30.0%) IRBD patients had phenoconversion, of which eight had DLB and one had Parkinson's disease with dementia. In Kaplan-Meier analysis, patients in the SVA-positive group converted to neurodegenerative dementia in a significantly shorter period of time compared to patients in the SVA-negative group.

CONCLUSIONS

These data suggest that SVA-positive IRBD patients have an increased short-term risk of developing neurodegenerative dementia.

[Analysis of brain perfusion single-photon emission tomography images using an easy Zscore imaging system for early diagnosis of Alzheimer's disease]

OBJECTIVE

To analyze single-photon emission tomography (SPECT) images of cerebral blood flow perfusion using an easy Z-score imaging system (eZIS) and explore the value of SPECT and eZIS in early diagnosis of Alzheimer's disease (AD).

METHODS

We retrospectively analyzed the clinical data of 71 subjects undergoing brain perfusion SPECT examination in our department from September, 2018 to September, 2020 and identified 31 eligible subjects for this study. Among these subjects, according to the NIA-AA criteria (2011 edition), 12 were diagnosed with mild cognitive impairment due to AD (MCI) and 11 with AD dementia stage (AD); 8 elderly subjects were healthy without cognitive impairment (NC). All these subjects underwent brain perfusion SPECT, and eZIS-assisted analysis was used to obtain the index values (severity, range and ratio). The differences in the severity, extent and ratio among the 3 groups were compared, and the diagnostic efficacy of single and joint analysis of the 3 indexes for early AD was analyzed.

RESULTS

There was no significant difference in gender, age and education level among the 3 groups (P>0.05). Compared with those in NC group, the Mini Mental State Examination Scale (MMSE) scores were significantly lowered in AD group and MCI group; the MMSE score was significantly lower in AD group than in MCI group (P < 0.05). The patients with AD had significantly greater disease severity and extent than those with MCI group; the severity, range and ratio in both AD group and MCI group were significantly higher than those of NC group, but the ratio did not differ significantly between AD group and MCI group (P>0.05). In single index analysis, severity had the highest diagnostic performance (AUC=0.911) and sensitivity (87.0%); the diagnostic performance and sensitivity of joint analysis were better than those of single analysis, and joint analysis of range and ratio showed high diagnostic performance (AUC=0.948) and sensitivity (87.0%).

CONCLUSION

The analysis of brain perfusion SPECT using an eZIS program can be useful for early diagnosis of AD.

Comparison of Alzheimer's disease patients and healthy controls in the easy Z-score imaging system with differential image reconstruction methods using SPECT/CT: verification using normal database of our institution

OBJECTIVE

The easy Z-score imaging system (eZIS) analysis is used for the diagnosis of dementia by cerebral blood flow on single photon emission computed tomography (SPECT). Differences in the acquisition and reconstruction conditions in SPECT may affect the eZIS analysis results. The present study aimed to construct our institutional normal database (NDB) and Alzheimer's disease (AD)-specific volumes of interest (VOIs) in eZIS analysis, and to compare the differential diagnostic ability between healthy controls (HC) and patients with AD in the image reconstruction filtered back projection (FBP) and ordered subset expectation maximization (OSEM) methods.

METHODS

An NDB was constructed at our institution from 30 healthy individual using the FBP and OSEM reconstruction methods. We divided 51 HC and 51 AD patients into two groups, one for AD disease-specific VOI construction (HC, AD) and the other for NDB verification (HC, AD); image reconstruction was performed using FBP and OSEM. The areas of reduced blood flow in AD patients were compared with those of HC using the two types of image reconstruction methods. We used AD disease-specific VOI and NDB from each reconstruction method in eZIS analysis and compared the differential diagnostic ability for HC and AD with the different reconstruction methods.

RESULTS

Comparing the areas of reduced blood flow in AD patients using the different image reconstruction methods, OSEM showed decreased blood flow in the medial region of the temporal lobes compared to FBP. Comparing the differential diagnostic ability for HC and AD using eZIS, the Severity, Extent, and Ratio showed higher values in the analysis performed using OSEM image reconstruction compared to FBP.

CONCLUSION

With the ^99mTc-ECD SPECT, the eZIS analysis equipped with our institutional AD-specific VOI and NDB using OSEM image reconstruction could distinguish HC from AD better than eZIS analysis using FBP image reconstruction. This study is registered in UMIN Clinical Trials Registry (UMIN-CTR) as UMIN study ID: UMIN000042362.

Utility of Easy Z-Score Imaging System-Assisted SPECT in Detecting Onset Age-Dependent Decreases in Cerebral Blood Flow in the Posterior Cingulate Cortex, Precuneus, and Parietal Lobe in Alzheimer's Disease with Amyloid Accumulation

Background

Easy Z-score imaging system (eZIS)-assisted SPECT accurately detects decreases in cerebral blood flow in the posterior cingulate cortex (PCC), precuneus, and parietal lobe, the cerebral regions deeply implicated in Alzheimer's disease (AD). Several studies suggested onset age-dependent decreases in cerebral blood flow in these regions in AD, but these studies did not screen for amyloid accumulation, suggesting inclusion of non-AD patients in their subjects.

Objective

By applying eZIS-SPECT to patients with amyloid deposition, it was the aim of this study to clarify onset age-dependent decreases in cerebral blood flow in the regions critical to AD.

Methods

We retrospectively analyzed eZIS-SPECT data on 34 AD patients with amyloid retention confirmed by ¹¹C-Pittsburgh compound B-PET. The subjects were divided into an early-onset group (n = 16) and a late-onset group (n = 18). The three indicators of the eZIS that had discriminated between AD patients and normal controls in previous studies were compared between the two groups.

Results

The mean values for the respective indicators were significantly higher in the early-onset group than in the late-onset group. Also, the proportion of patients with abnormalities in all indicators was significantly higher in the early-onset group (93.8%) than in the late-onset group (50.0%).

Conclusions

The present study, applying eZIS-SPECT to amyloid-positive AD patients, suggests that reduced cerebral blood flow in the PCC, precuneus, and parietal lobe is more pronounced in the early-onset type than in the late-onset type of the disease.