Comparison of the decreases in regional cerebral blood flow in the posterior cingulate cortex, precuneus, and parietal lobe between suspected non-Alzheimer's disease pathophysiology and Alzheimer's disease

Longitudinal Changes of Regional Cerebral Blood Flow on a Single-Photon Emission Computed Tomography (SPECT) Scan in a Patient With Schizophrenia Having Cotard's Syndrome

Cotard's syndrome is a rare clinical condition characterized by the presence of nihilistic delusions, delusions of immortality, depressive mood, and anxiety. Longitudinal changes in regional cerebral blood flow (rCBF) obtained under different conditions with and without Cotard's syndrome have rarely been reported in the literature. We report a case of a patient with Cotard's syndrome in whom longitudinal rCBF was assessed using single-photon emission computed tomography (SPECT). The patient was a 52-year-old man suffering from schizophrenia and mild mental retardation. He was transported to our hospital because of lumbar fractures caused by a suicidal attempt. In the second week after admission, he displayed Cotard's syndrome, i.e., nihilistic delusions, suicidal thoughts, and depressive mood. SPECT with 99mTc-ethyl cysteinate dimer was performed, and the rCBF increased in the bilateral prefrontal cortex but decreased in the occipital and parietal lobes. He was treated with pharmacotherapy mainly using lurasidone, and his Cotard's symptoms disappeared. SPECT was performed again. The increased rCBF in the bilateral prefrontal cortex and the decreased rCBF in the right occipital and parietal lobes were improved. The present case suggests that increased rCBF in the prefrontal cortex and decreased rCBF in the right occipital and parietal lobes are associated with the development of Cotard's syndrome.

Towards Improved Clinical Diagnosis of Argyrophilic Grain Disease Using Brain Imaging

In this issue, Sakurai et al. report on relevant findings for the clinical diagnosis of argyrophilic grain disease (AGD). Their study describes a characteristic atrophy distribution restricted to the limbic lobes, namely the ambient gyrus, in AGD versus Alzheimer's disease (AD), in pathologically confirmed patients using magnetic resonance imaging by voxel- and surface-based morphometry. Here, we discuss the possibility of employing functional or molecular brain imaging to further improvement of diagnosis of AGD. Additional research is required to elucidate the contributions of comorbid AD and transactive response DNA-binding protein 43 kDa pathologies in patients with AGD.

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.

Altered cerebral blood flow in older adults with Alzheimer's disease: a systematic review

The prevalence of Alzheimer's disease is projected to reach 13 million in the U.S. by 2050. Although major efforts have been made to avoid this outcome, so far there are no treatments that can stop or reverse the progressive cognitive decline that defines Alzheimer's disease. The utilization of preventative treatment before significant cognitive decline has occurred may ultimately be the solution, necessitating a reliable biomarker of preclinical/prodromal disease stages to determine which older adults are most at risk. Quantitative cerebral blood flow is a promising potential early biomarker for Alzheimer's disease, but the spatiotemporal patterns of altered cerebral blood flow in Alzheimer's disease are not fully understood. The current systematic review compiles the findings of 81 original studies that compared resting gray matter cerebral blood flow in older adults with mild cognitive impairment or Alzheimer's disease and that of cognitively normal older adults and/or assessed the relationship between cerebral blood flow and objective cognitive function. Individuals with Alzheimer's disease had relatively decreased cerebral blood flow in all brain regions investigated, especially the temporoparietal and posterior cingulate, while individuals with mild cognitive impairment had consistent results of decreased cerebral blood flow in the posterior cingulate but more mixed results in other regions, especially the frontal lobe. Most papers reported a positive correlation between regional cerebral blood flow and cognitive function. This review highlights the need for more studies assessing cerebral blood flow changes both spatially and temporally over the course of Alzheimer's disease, as well as the importance of including potential confounding factors in these analyses.

Comparing Medial Temporal Atrophy Between Early-Onset Semantic Dementia and Early-Onset Alzheimer's Disease Using Voxel-Based Morphometry: A Multicenter MRI Study

BACKGROUND

Early-onset Semantic dementia (EOSD) and early-onset Alzheimer's disease (EOAD) are often difficult to clinically differentiate in the early stages of the diseases because of the overlaps of clinical symptoms such as language symptoms. We compared the degree of atrophy in medial temporal structures between the two types of dementia using the voxel-based specific regional analysis system for Alzheimer's disease (VSRAD).

METHODS

The participants included 29 (age: 61.7±4.5 years) and 39 (age: 60.2±4.9 years) patients with EOSD and EOAD, respectively. The degree of atrophy in medial temporal structures was quantified using the VSRAD for magnetic resonance imaging data. Receiver operating characteristic (ROC) analysis was performed to distinguish patients with EOSD and EOAD using the mean Z score (Z-score) in bilateral medial temporal structures and the absolute value (laterality score) of the laterality of Z-score (| right-left |) for indicating the degree of asymmetrical atrophy in medial temporal structures.

RESULTS

The EOSD group had significantly higher Z and laterality scores than the EOAD group (Zscores: mean ± standard deviation: 3.74±1.05 vs. 1.56±0.81, respectively; P<0.001; laterality score: mean ± standard deviation: 2.35±1.23 vs. 0.68±0.51, respectively; P<0.001). In ROC analysis, the sensitivity and specificity to differentiate EOSD from EOAD by a Z-score of 2.29 were 97% and 85%, respectively and by the laterality score of 1.05 were 93% and 85%, respectively.

CONCLUSION

EOSD leads to more severe and asymmetrical atrophy in medial temporal structures than EOAD. The VSRAD may be useful to distinguish between these dementias that have several clinically similar symptoms.

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.