The evaluation of brain perfusion SPECT using an easy Z-score imaging system in the mild cognitive impairment subjects with brain amyloid-β deposition

Oscillatory characteristics of resting-state magnetoencephalography reflect pathological and symptomatic conditions of cognitive impairment

Background

Dementia and mild cognitive impairment are characterised by symptoms of cognitive decline, which are typically assessed using neuropsychological assessments (NPAs), such as the Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). Magnetoencephalography (MEG) is a novel clinical assessment technique that measures brain activities (summarised as oscillatory parameters), which are associated with symptoms of cognitive impairment. However, the relevance of MEG and regional cerebral blood flow (rCBF) data obtained using single-photon emission computed tomography (SPECT) has not been examined using clinical datasets. Therefore, this study aimed to investigate the relationships among MEG oscillatory parameters, clinically validated biomarkers computed from rCBF, and NPAs using outpatient data retrieved from hospital records.

Methods

Clinical data from 64 individuals with mixed pathological backgrounds were retrieved and analysed. MEG oscillatory parameters, including relative power (RP) from delta to high gamma bands, mean frequency, individual alpha frequency, and Shannon's spectral entropy, were computed for each cortical region. For SPECT data, three pathological parameters-'severity', 'extent', and 'ratio'-were computed using an easy z-score imaging system (eZIS). As for NPAs, the MMSE and FAB scores were retrieved.

Results

MEG oscillatory parameters were correlated with eZIS parameters. The eZIS parameters associated with Alzheimer's disease pathology were reflected in theta power augmentation and slower shift of the alpha peak. Moreover, MEG oscillatory parameters were found to reflect NPAs. Global slowing and loss of diversity in neural oscillatory components correlated with MMSE and FAB scores, whereas the associations between eZIS parameters and NPAs were sparse.

Conclusion

MEG oscillatory parameters correlated with both SPECT (i.e. eZIS) parameters and NPAs, supporting the clinical validity of MEG oscillatory parameters as pathological and symptomatic indicators. The findings indicate that various components of MEG oscillatory characteristics can provide valuable pathological and symptomatic information, making MEG data a rich resource for clinical examinations of patients with cognitive impairments. SPECT (i.e. eZIS) parameters showed no correlations with NPAs. The results contributed to a better understanding of the characteristics of electrophysiological and pathological examinations for patients with cognitive impairments, which will help to facilitate their co-use in clinical application, thereby improving patient care.

Using eZIS of SPECT to evaluate the therapeutic effect of carotid endarterectomy

OBJECTIVE

Stroke is an acute cerebrovascular disease with high morbidity and mortality. The main causes of ischemic stroke include carotid artery stenosis, and carotid endarterectomy (CEA) can be used to improve the blood flow of the lesion site. Regional cerebral blood flow (rCBF) can be decreased by using single photon emission computed tomography (SPECT). The Easy Z-Score imaging system (eZIS) can display the changes of rCBF as Z-Score. The purpose of this study was to determine whether eZIS of SPECT can be used to evaluate the therapeutic effect of CEA in the treatment of carotid artery stenosis.

METHODS

In this study, subjects were divided into the surgery group and the control group. The surgery group included seven patients with unilateral or bilateral internal carotid artery stenosis who received CEA treatment, and the control group included 11 patients who only received conventional drug treatment but did not receive surgery. Cerebral perfusion imaging (CPI) was collected twice before and after the corresponding treatment (within 6 months). rCBF of the lesion site was measured and Z-score was calculated before and after treatment by the eZIS technique.

RESULTS

The postoperative Z-score of the surgery group was 0.54 ± 2.71 compared with that of the preoperative -1.34 ± 2.68 ( P  = 0.0034; t  = 4.687; df  = 6), while the z-score of the control group was -0.33 ± 2.58 compared with that of the pretreatment 1.84 ± 2.62 ( P  = 0.0010; t  = 4.618; df  = 10).

CONCLUSION

CEA can effectively improve the blood flow in the lesion area of patients with carotid artery stenosis. eZIS of SPECT can be used to evaluate the therapeutic effect of CEA on carotid artery stenosis visually.

Experimental evaluation of absolute quantification in 99m Tc-TRODAT-1 SPECT/CT brain dopamine transporter (DAT) studies

Objective

To evaluate the quantitative accuracy of clinical brain dopamine transporters (DAT) investigations utilizing ^99mTc‐TRODAT‐1 single‐photon emission computed tomography (SPECT)/computed tomography (CT) in experimental and clinical settings.

Materials and methods

The study used an experimental phantom evaluation and a clinical dataset. Three‐dimensional‐ordered subsets expectation–maximization reconstructed the original and resampled datasets using attenuation correction, scatter correction, and resolution recovery. The reconstructed data were analyzed and reported as percentage difference, standardized uptake value reference (SUVr), and a coefficient of variation (CoV). The Taguchi method tested the impact of the three different parameters on signal‐to‐noise ratio (SNR) and SUVr, including number iteration, Poisson resampling, and phantom setup, with and without the plaster of Paris (POP). Six ^99mTc‐TRODAT‐1 SPECT/CT scans were acquired in healthy subjects for verification purposes.

Results

The percentage activity difference between the phantom with and without POP is 20% and 5%, respectively. The SUVr reveals a 10% underestimate for both with and without POP. When it comes to the influence of Poisson resampling, the SUVr value for 75% Poisson resampling indicates 10% underestimation on both sides of the caudate and putamen area, with and without POP. When 25% of Poisson resampling is applied, the SUVr value is overestimated (±35%). In the Taguchi analysis, iteration numbers were the most dominant factor with the F‐value of 9.41 and the contribution rate of 52.66% (p < 0.05) for SNR. In comparison, F‐value of 9.1 for Poisson resampled with contribution rate of 58.91% (p < 0.05) for SUVr. Reducing counts by 25% from the original dataset resulted in a minimal bias in SUVr, compared to 50% and 75%.

Conclusion

The optimal absolute SPECT/CT quantification of brain DAT studies using ^99mTc‐TRODAT‐1 appears achievable with at least 4i10s and SUVr as the surrogate parameter. In clinical investigations, it is possible to reduce the recommended administered dose by up to 25% while maintaining accurate measurement.

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.

A New Serum Biomarker Set to Detect Mild Cognitive Impairment and Alzheimer's Disease by Peptidome Technology

Background:

Because dementia is an emerging problem in the world, biochemical markers of cerebrospinal fluid (CSF) and radio-isotopic analyses are helpful for diagnosing Alzheimer’s disease (AD). Although blood sample is more feasible and plausible than CSF or radiological biomarkers for screening potential AD, measurements of serum amyloid- β (Aβ), plasma tau, and serum antibodies for Aβ_1 - 42 are not yet well established.

Objective:

We aimed to identify a new serum biomarker to detect mild cognitive impairment (MCI) and AD in comparison to cognitively healthy control by a new peptidome technology.

Methods:

With only 1.5μl of serum, we examined a new target plate “BLOTCHIP^®” plus a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) to discriminate control (n = 100), MCI (n = 60), and AD (n = 99). In some subjects, cognitive Mini-Mental State Examination (MMSE) were compared to positron emission tomography (PET) with Pittsburgh compound B (PiB) and the serum probability of dementia (SPD). The mother proteins of candidate serum peptides were examined in autopsied AD brains.

Results:

Apart from Aβ or tau, the present study discovered a new diagnostic 4-peptides-set biomarker for discriminating control, MCI, and AD with 87% of sensitivity and 65% of specificity between control and AD (^***p < 0.001). MMSE score was well correlated to brain Aβ deposition and to SPD of AD. The mother proteins of the four peptides were upregulated for coagulation, complement, and plasticity (three proteins), and was downregulated for anti-inflammation (one protein) in AD brains.

Conclusion:

The present serum biomarker set provides a new, rapid, non-invasive, highly quantitative and low-cost clinical application for dementia screening, and also suggests an alternative pathomechanism of AD for neuroinflammation and neurovascular unit damage.

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.

Transcatheter aortic valve implantation and cognitive function in elderly patients with severe aortic stenosis

AIMS

The aim of this study was to examine the mechanisms of cognitive impairment and reversibility in elderly patients with severe aortic stenosis (AS) after transcatheter aortic valve implantation (TAVI) with special reference to cerebral blood flow (CBF).

METHODS AND RESULTS

We examined 15 elderly patients with severe AS (mean age 83.2±4.5 years, 12 female) who underwent TAVI. Before and three months after TAVI, we evaluated cognitive function with the Logical Memory II test (LM II), cardiac output (CO) with echocardiography, and CBF with 99mTc single-photon emission computed tomography (SPECT). LM II score and CO were significantly increased after TAVI compared with baseline (p<0.01 for LM II, p<0.005 for CO). Notably, CBF in the local regions, including that in the right hippocampus, was significantly increased after TAVI (p<0.005 at each voxel). The patients with increased CO after TAVI also showed significantly increased CBF in the right hippocampus compared with those without it (p<0.01). Importantly, CBF in the right hippocampus was positively correlated with LM II scores (p<0.05).

CONCLUSIONS

These results provide the first evidence that TAVI may improve cognitive functions associated with increased cerebral perfusion especially in the hippocampus in elderly patients with severe AS.

Diagnosis of mild cognitive impairment using multiple neuroimaging modalities in addition to the Mini-Mental State Examination

AIM

This prospective study investigated the additional utility of combining multiple imaging modalities with the Mini-Mental State Examination (MMSE) in discriminating individuals with mild cognitive impairment (MCI) from cognitively normal individuals.

METHODS

A total of 103 individuals with amnestic MCI and normal cognitive function were recruited from outpatients; they underwent examination using the MMSE, magnetic resonance imaging, ¹⁸ F-fluorodeoxyglucose positron emission tomography and ¹¹ C-Pittsburgh compound B positron emission tomography. Binary logistic regression with receiver operator characteristic analysis was used to assess the combination of the abovementioned single or multiple imaging modalities with the MMSE. Eight models were constructed, and their area under the curve values and misclassification rates in discriminating individuals with amnestic MCI from cognitively normal individuals were evaluated.

RESULTS

The addition of each of the imaging modalities improved the discrimination accuracy over that of the MMSE alone; the accuracy obtained with the addition of ¹⁸ F-fluorodeoxyglucose positron emission tomography was the highest. The best model with the highest accuracy included a combination of all the imaging modalities in addition to the MMSE (area under the curve value 0.902).

CONCLUSIONS

The combination of all the imaging modalities in addition to the MMSE could facilitate more accurate diagnosis of amnestic MCI. Of the individual imaging modalities, the highest accuracy resulted from the addition of ¹⁸ F-fluorodeoxyglucose positron emission tomography to the MMSE. Geriatr Gerontol Int 2019; 19: 1193-1197.

Relationship Between the Japanese Version of the Montreal Cognitive Assessment and PET Imaging in Subjects with Mild Cognitive Impairment

BACKGROUND

The Montreal Cognitive Assessment (MoCA) test has high sensitivity and specificity for detecting mild cognitive impairment or early dementia. How the MoCA score relates to findings of positron emission tomography imaging, however, remains unclear.

OBJECTIVE

This prospective study examined the relationship between the Japanese version of the MoCA (MoCA-J) test and brain amyloid deposition or cerebral glucose metabolism among subjects with mild cognitive impairment.

METHODS

A total of 125 subjects with mild cognitive impairment underwent the MoCA-J test, and amyloid- and 18F-fluorodeoxyglucose- positron emission tomography. Linear correlation analysis and multiple linear regression analysis were conducted to investigate the relationship between the MoCA-J score and demographic characteristics, amyloid deposition, and cerebral glucose metabolism. Moreover, Statistical Parametric Mapping 8 was used for a voxel-wise regression analysis of the MoCA-J score and cerebral glucose metabolism.

RESULTS

The MoCA-J score significantly correlated with age, years of education, and the Mini-Mental State Examination score. After adjusting for age, sex, and education, the MoCA-J score significantly correlated negatively with amyloid retention (β= -0.174, p= 0.031) and positively with cerebral glucose metabolism (β= 0.183, p= 0.044). Statistical Parametric Mapping showed that Japanese version of MoCA score correlated with glucose metabolism in the bilateral frontal and parietal lobes, and the left precuneus.

CONCLUSION

The total MoCA-J score correlated with amyloid deposition and frontal and parietal glucose metabolism in subjects with mild cognitive impairment. Our findings support the usefulness of the MoCA-J test for screening subjects at high risk for Alzheimer's disease.