Development of quantitative analysis method for stereotactic brain image: assessment of reduced accumulation in extent and severity using anatomical segmentation

Case series of patients with early psychosis presenting hypoperfusion in angular gyrus and self-disturbance: Implication for the sense of agency and schizophrenia

BACKGROUND

Self-disturbance has been considered as a core symptomatology of schizophrenia and its emergence from the prodromal phase makes it a crucial target for early detection and intervention in schizophrenia. Currently, the clinical assessment of self-disturbance relies on the self-report of patients, and clinicians have no diagnostic tools in clinical practice. Identifying the neural substrate of self-disturbance would be of great clinical value by shedding light on the core dimension of schizophrenia.

CASE PRESENTATION

We first introduce an adolescent patient who initially presented self-disturbance, and clinically detectable hypoperfusion in angular gyrus (AG) was observed when early psychosis was suspected. Interestingly, the hypoperfusion in AG may correspond to improvement and exacerbation of self-disturbance. This clinical observation led us to pursue the relationship between the decreased blood flow in the AG and self-disturbance. Among 15 cases with suspected early psychosis in which single photon emission computed tomography was performed to exclude organic factors, we found additional 5 cases, including one prodromal patient, showing hypoperfusion in the AG and self-disturbance with significant correlation (r = 0.79, p = 0.00025).

DISCUSSION

The self-disturbance has been interpreted as a reflection of disturbance of the "Sense of Agency", the ability to attribute their action and/or thoughts to themselves. AG has been shown to play a pivotal role in the sense of agency. These cases suggest that the hypoperfusion in AG associated with the disruption in the sense of agency would be an early clinical sign of schizophrenia. Further longitudinal studies are needed to test this hypothesis.

Using eZIS to Predict Progression from MCI to Dementia in Three Years

(1) Background: Mild cognitive impairment (MCI) due to Alzheimer's disease (AD) progresses to dementia at a higher annual rate, while other MCIs may remain stable or even improve over time. Discriminating progressive from non-progressive cases of MCI is crucial and challenging. (2) Methods: A retrospective study of individuals with MCI was conducted at a university hospital located in southern Taiwan. The researchers collected demographic data, comorbidities, the scores of cognitive tests, three easy Z-score imaging system (eZIS) indicators (severity, extent, and ratio), Fazekas scale scores, mesial temporal atrophy (MTA) scores, clinical outcomes including deterioration of Cognitive Abilities Screening Instrument, Mini-mental State Examination, Clinical Dementia Rating Sum of Box scores, and the conversion from MCI to dementia. Those who converted to dementia in three years and non-converters were compared by the three eZIS indicators to test the predictive utility, and the clinical outcomes were evaluated by regression and ROC curve analysis. (3) Results: The three eZIS indicators were significantly higher in the group of progressive MCI than in stable MCI. eZIS severity is positively correlated with a deterioration in the scores of the Cognitive Abilities Screening Instrument and Clinical Dementia Rating Sum of Box. eZIS severity is also positively correlated with conversion from MCI to dementia. The AUC for severity is 0.719, and the optimal cutoff value of severity for predicting conversion is 1.22. (4) Conclusions: During three years of follow-up, MCI individuals with greater eZIS severity were significantly associated with worse cognitive assessment scores and a higher conversion rate to dementia.

Cerebellar blood perfusion is a diagnostic, but not a prognostic, marker for parkinsonian-dominant type multiple system atrophy

INTRODUCTION

Multiple system atrophy (MSA) is clinically characterized by various neurological symptoms. According to the diagnostic criteria, MSA is classified into parkinsonian-dominant type (MSA-P) or cerebellar ataxia-dominant type (MSA-C) based on the predominant signs displayed. Recently, N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT), a radiological examination evaluating brain perfusion, has been successful in detecting cerebellar hypoperfusion in MSA-P patients, demonstrating its utility in the early detection of cerebellar dysfunction. In this study, we further explored whether this cerebellar hypoperfusion impacts the clinical features of MSA-P, whether it is observable in patients without cerebellar symptoms, and, most importantly, whether it influences the prognosis of MSA-P.

METHODS

We conducted a retrospective analysis of 88 MSA patients who were admitted to our department for the last fifteen years. Clinical data were collected, and cerebellar perfusion was examined using 123I-IMP SPECT. This analysis includes the application of the three-dimensional stereotactic surface projection (3D-SSP) technique and Z-score.

RESULTS

Cerebellar perfusion decreased in MSA-P patients without cerebellar ataxia, compared to healthy individuals (p = 0.0017). The Receiver Operating Characteristic (ROC) curve demonstrated a moderate ability to distinguish MSA-P patients without cerebellar ataxia (MSA-Pp) from healthy controls (AUC = 0.6832). Among MSA-Pp, those exhibiting cerebellar hypoperfusion showed relatively improved neurological prognosis, although the difference was not statistically significant when compared to those with normal cerebellar perfusion.

CONCLUSION

Assessing cerebellar perfusion through IMP-SPECT proves valuable in detecting subclinical cerebellar dysfunction in MSA-Pp. Importantly, cerebellar hypoperfusion does not correlate with a poorer neurological prognosis.

Diagnostic approach with Z-score mapping to reduce artifacts caused by cerebral atrophy in regional CBF assessment of mild cognitive impairment (MCI) and Alzheimer's disease by [99mTc]-ECD and SPECT

PURPOSE

The aim of this study was to develop a novel approach that enhanced diagnostic accuracy in the diagnosis of mild cognitive impairment (MCI) and early Alzheimer's disease (AD) using cerebral perfusion SPECT by minimizing artifacts caused by cerebral atrophy.

MATERIALS AND METHODS

[99mTc]-ECD and SPECT studies were performed on 15 cognitively normal patients, 40 patients with MCI, and 16 patients with AD. SPECT images were compared using SPM. The atrophy correction method was incorporated to reduce artifacts through the MRI masking procedure. Regional Z-score, percent extent, and atrophy correction rate were obtained and compared. The Z-score mapping program was structured as a single package that ran semi-automatically.

RESULTS

The method significantly reduced regional Z-score in most regions, leading to improved estimates. The mean atrophy correction rate ranged from 10.4 to 12.0%. In MCI and AD, the convexities of the frontal and parietal lobes and the posterior medial cerebrum were particularly sensitive to cerebral atrophy, and the Z-scores were overestimated, whereas the posterior cingulate cortex and the cerebellum were less sensitive. The diagnostic accuracy for MCI increased from 67 to 69% and for AD from 78 to 82%.

CONCLUSION

The proposed approach provided more precise Z-scores with less over- or underestimation, artifacts, and improved diagnostic accuracy, being recommended for clinical studies.

Noise Pareidolia Test in Parkinson's Disease and Atypical Parkinsonian Syndromes: A Retrospective Study

INTRODUCTION

Pareidolias, or visual misperceptions, are a non-motor symptom of Parkinson's disease (PD) with unclear pathophysiology. The noise pareidolia test (NPT) is a tool for screening pareidolias. The usefulness of the NPT in differentiating PD from atypical parkinsonian syndromes (APS) is also unknown.

METHODS

We retrospectively investigated 74 patients with PD and 18 patients with APS who took the NPT. Correlations between the number of pareidolic responses, gray matter volume, and cerebral blood flow were also examined in the patients with PD.

RESULTS

The median number of pareidolic responses in patients with PD and patients with APS was 0 (interquartile range (IQR): 0-3) and 0 (IQR: 0-1), respectively, and tended to be higher in patients with PD than in those with APS (p = 0.077). It was significantly higher in patients with PD who had hallucinations (2; IQR: 0-9) (p = 0.016). The area under the receiver operating characteristic curve for the number of pareidolic responses in the NPT was 0.62 when used to differentiate PD and APS, and the optimal cutoff number of pareidolic responses was 2/3. Sensitivity and specificity were 25.7% and 100%, respectively. In the PD group, the number of pareidolic responses was correlated with age (r = 0.27; p = 0.021) and the Frontal Assessment Battery (FAB) score (r = -0.34; p = 0.0099). Magnetic resonance imaging showed no significant correlation between the number of pareidolic responses and the volume of focal gray matter. On cerebral hypoperfusion mapping, the left parietal lobe had a significant correlation with the number of pareidolic responses (r = 0.35; p = 0.027).

CONCLUSION

The number of pareidolic responses in NPT was suggested to be useful as a red flag to rule out APS in differentiating PD from APS. In PD without dementia, the number of pareidolic responses was associated with reduced blood flow in the left parietal lobe.

Syntactic Impairment Associated with Hypoperfusion in the Left Middle and Inferior Frontal Gyri after Right Cerebellar Hemorrhage

Cerebellar injuries can cause syntax impairments. Cortical dysfunction due to cerebello-cerebral diaschisis is assumed to play a role in this phenomenon. Functional magnetic resonance imaging studies have repeatedly shown the activation of Broca's area in response to syntactic tasks. However, there have been no reports of selective syntax impairment and hypoperfusion restricted to this area after cerebellar injury. We herein report a patient with right cerebellar hemorrhage that led to marked syntax impairment along with severe hypoperfusion confined to the Brodmann area (BA) 45 (anterior part of Broca's area) and BA46.

Association of auditory Charles Bonnet syndrome with increased blood flow in the nondominant Brodmann area 22

Aim

Auditory Charles Bonnet syndrome (aCBS) is characterized by musical hallucinations (MHs) that accompany acquired hearing impairments. This hallucination is the acoustic perception of music, sounds, or songs in the absence of an outside stimulus, and it may be associated with hyperactivity of the superior temporal lobes. Some studies have reported the possibility of improving MH with antiepileptics. To elucidate in detail the brain regions responsible for aCBS, we analyzed the regions that changed functionally after treatment.

Methods

Before and after treatment with carbamazepine (four cases), clonazepam (one case), and a hearing aid (one case), cerebral perfusion single-photon emission computed tomography (SPECT) and the Auditory Hallucination Rating Scale (AHRS) were applied to six patients with hearing-loss-associated MHs.

Results

Cerebral blood flow analysis using SPECT revealed hyperperfusion in Brodmann area (BA) 22-the posterior region of the superior temporal gyrus-in the nondominant hemisphere in all six patients in the pretreatment phase. After treatment, the hyperperfusion region improved in all patients. The area percentages with hyperperfusion in the nondominant BA22 were strongly positively correlated with the AHRS score.

Conclusion

The results suggest that aCBS, which was treatable with antiepileptics or hearing aids, was involved in hyperexcitement in BA22, and that MH strength was correlated with degree of excitement.

Prediction of voluntary movements of the upper extremities by resting state-brain regional glucose metabolism in patients with chronic severe brain injury: A pilot study

Confirmation of the exact voluntary movements of patients with disorder of consciousness following severe traumatic brain injury (TBI) is difficult because of the associated communication disturbances. In this pilot study, we investigated whether regional brain glucose metabolism assessed by ¹⁸ F-fluorodeoxyglucose positron emission tomography (FDG-PET) at rest could predict voluntary movement in severe TBI patients, particularly those with sufficient upper limb capacity to use communication devices. We visually and verbally instructed patients to clasp or open their hands. After video capture, three independent rehabilitation therapists determined whether the patients' movements were voluntary or involuntary. The results were compared with the standardized uptake value in the primary motor cortex, referring to the Penfield's homunculus, by resting state by FDG-PET imaged 1 year prior. Results showed that glucose uptake in the left (p = 0.0015) and right (p = 0.0121) proximal limb of the primary motor cortex, based on Penfield's homunculus on cerebral cartography, may reflect contralateral voluntary movement. Receiver operating characteristic curve analysis showed that a mean cutoff standardized uptake value of 5.47 ± 0.08 provided the best sensitivity and specificity for differentiating between voluntary and involuntary movements in each area. FDG-PET may be a useful and robust biomarker for predicting long-term recovery of motor function in severe TBI patients with disorders of consciousness.

Oral environment and cerebral blood flow in patients with neurodegenerative dementia: comparison of Alzheimer type dementia and dementia with Lewy bodies

BACKGROUND

The number of patients with dementia is increasing worldwide. Modifying risk factors may significantly reduce the prevalence and cost of dementia. The number of remaining teeth, occlusal force, denture use, and periodontal disease status are associated with the risk of developing dementia. The oral environment may be a risk factor for dementia. This study aimed to investigate the association between the oral environment and cerebral blood flow in patients with mild cognitive impairment and dementia (either Alzheimer type dementia (ATD) or dementia with Lewy bodies (DLB)). We aimed to identify differences in the oral environment according to the underlying neurodegenerative disease.

METHODS

The participants were 25 patients with ATD and 25 patients with DLB who visited the Department of Dementia and Geriatric Medicine, Kanagawa Dental University Hospital. Patients were diagnosed with ATD and DLB by well-trained specialists certified by the Japanese Dementia Society and categorised as Level 3 or 4 by the Functional Assessment Staging of Alzheimer Disease scale. The correlation between oral environment (number of teeth, periodontal tissue, and oral function) and cerebral blood flow in each brain area calculated by single photon emission computed tomography was examined.

RESULTS

The DLB group showed a significant correlation between masticatory performance and cerebral blood flow in some areas, while no such correlation was observed in the ATD group. Significant correlations were found between periodontal pocket depth and bleeding on probing and cerebral blood flow in some areas in both groups, although the correlation was considerable in the ATD group.

CONCLUSIONS

The results of this study suggest that the association between changes in the oral environment and cerebral blood flow may differ among patients with ATD and DLB, depending on the underlying causative disease.

Persistent brain damage in reversible cerebral vasoconstriction syndrome on 99mTc-ethyl cysteinate dimer single-photon emission computed tomography: A long-term observational study

BACKGROUND

Blood-brain barrier (BBB) breakdown is considered a key step in the pathophysiology of reversible cerebral vasoconstriction syndrome (RCVS); however, its temporal course remains unclear. Based on the characteristics and dynamics of ^99mTc-ethyl cysteinate dimer (^99mTc-ECD) as a tracer, ^99mTc-ECD single-photon emission computed tomography (SPECT) can detect not only hypoperfusion but also BBB breakdown and/or brain tissue damage. Therefore, this study aimed to investigate this course using ^99mTc-ECD SPECT.

METHODS

Between 2011 and 2019, we enrolled seven patients (one male and six female patients) with RCVS without ischemic or hemorrhagic stroke or posterior reversible encephalopathy syndrome. ^99mTc-ECD SPECT was performed repeatedly in each patient. SPECT data were statistically analyzed using an easy Z-score imaging system.

RESULTS

Thunderclap headache was the initial symptom in all the patients and was most commonly triggered by bathing (three patients). All the patients exhibited vasoconstriction and reduced cerebral uptake of ^99mTc-ECD during the acute stage. Follow-up assessment from 3 to 16 months showed that reduced cerebral uptake persisted in all the patients, even after the vasoconstriction had resolved.

CONCLUSION

Reduced cerebral uptake of ^99mTc-ECD persisted in the late stage of RCVS, even after vasoconstriction and headache subsided. BBB breakdown and/or brain tissue damage may underlie this phenomenon. ^99mTc-ECD SPECT is an effective neuroimaging method to detect brain functional abnormalities, reflecting BBB breakdown or tissue damages, throughout the treatment course of RCVS.

Quantitative regional cerebral blood flow measurement using near-infrared spectroscopy and indocyanine green in patients undergoing superficial temporal to middle cerebral artery bypass for moyamoya disease: a novel method using a frequency filter

Measuring regional cerebral blood flow (rCBF) after revascularization for moyamoya disease, as a type of ischemic cerebrovascular disease, is crucial. This study aims to validate our novel technology that combines near-infrared spectroscopy (NIRS) with a frequency filter to extract the arterial component. We measured rCBF before and after revascularization for moyamoya disease and at the end of the surgery using NIRO-200NX (Hamamatsu Photonics, Japan) and indocyanine green (ICG). rCBF was calculated using Fick's principle, change in arterial ICG concentrations, and maximum arterial ICG concentration. rCBF measured with NIRS (rCBF_N) was compared with pre- and postoperative rCBF measured with SPECT (rCBF_S). Thirty-four procedures were analyzed. rCBF_N increased from baseline to end of the surgery (mean difference (MD), 2.99 ml/min/100 g; 95% confidence interval (CI), 0.40-5.57 ml/min/100 g on the diseased side; MD, 4.94 ml/min/100 g; 95% CI, 2.35-7.52 ml/min/100 g on the non-diseased side). Similar trends were observed for rCBF_S (MD, 3.98 ml/min/100 g; 95% CI, 2.30-5.67 ml/min/100 g on the diseased side; MD, 2.77 ml/min/100 g; 95% CI, 1.09-4.45 ml/min/100 g on the non-diseased side). Intraclass correlations 3 (ICC3s) between rCBF_N and rCBF_S were weak on the diseased side (ICC3, 0.25; 95% CI, -0.03-0.5; p = 0.07) and the non-diseased side (ICC3, 0.24; 95% CI, -0.05-0.5; p = 0.08). rCBF measurements based on this novel method were weakly correlated with rCBF measurements with SPECT.

Neuronal Alterations in Secondary Thalamic Degeneration Due to Cerebral Infarction: A 11 C-Flumazenil Positron Emission Tomography Study

Studies using animal experiments have shown secondary neuronal degeneration in the thalamus after cerebral infarction. Neuroimaging studies in humans have revealed changes in imaging parameters in the thalamus, remote to the infarction. However, few studies have directly demonstrated neuronal changes in the thalamus in vivo. The purpose of this study was to determine whether secondary thalamic neuronal damage may manifest as a decrease in central benzodiazepine receptors in patients with cerebral infarction and internal carotid artery or middle cerebral artery disease.

Increased cerebrovascular reactivity in selected brain regions after extracranial-intracranial bypass improves the speed and accuracy of visual cancellation in patients with severe steno-occlusive disease: a preliminary study

The effect of the change in cerebrovascular reactivity (CVR) in each brain area on cognitive function after extracranial-intracranial bypass (EC-IC bypass) was examined. Eighteen patients who underwent EC-IC bypass for severe unilateral steno-occlusive disease were included. Single-photon emission CT (SPECT) for evaluating CVR and the visual cancellation (VC) task were performed before and after surgery. The accuracy of VC was expressed by the arithmetic mean of the age-matched correct answer rate and the accurate answer rate, and the averages of the time (time score) and accuracy (accuracy score) of the four VC subtests were used. The speed of VC tended to be slower, whereas accuracy was maintained before surgery. The EC-IC bypass improved CVR mainly in the cerebral hemisphere on the surgical side. On bivariate analysis, when CVR increased post-operatively, accuracy improved on both surgical sides, but the time score was faster on the left and slower on the right surgical side. Stepwise multiple regression analysis showed that the number of the brain regions associated with the time score was 5 and that associated with the accuracy score was 4. In the hemodynamically ischemic brain, processing speed might be adjusted so that accuracy would be maintained based on the speed-accuracy trade-off mechanism that may become engaged separately in the left and right cerebral hemispheres when performing VC. When considering the treatment for hemodynamic ischemia, the relationship between CVR change and the speed-accuracy trade-off in each brain region should be considered.

Whole-body vibration exercise and training increase regional CBF in mild cognitive impairment with enhanced cognitive function

OBJECTIVES

Preclinical and non-medicinal interventions are essential for preventing and treating cognitive decline in patients with mild cognitive impairment (MCI). Whole-body vibration (WBV) exercise is conducted on a platform that generates vertical sinusoidal vibrations, and WBV training may improve regional cerebral blood flow (rCBF) and cognitive function, however, the underlying mechanism remains unclear. The aim of the present study was to investigate whether WBV exercise and a 24-week WBV training protocol increased rCBF and enhanced cognitive function in patients with amnestic MCI (aMCI).

METHODS

[99mTc]-ECD and SPECT studies were performed on 16 aMCI patients at baseline, during WBV exercise, and on 6 of the 16 patients after 24-week WBV training. To diagnose SPECT images and select the patients, a Z-score mapping approach was used, which revealed pathological hypoperfusion in the parietal association cortex, precuneus and/or posterior cingulate gyrus for MCI at baseline. rCBF was semi-quantitatively measured and underestimation in the high flow range was corrected. Since it is difficult to quantitatively measure rCBF during WBV exercise, the rCBFratio was obtained by standardizing with the average of individual mean SPECT counts with correcting underestimation in the high flow range. The rCBFratios at baseline and after WBV training were also obtained in a similar manner. Since the changes in rCBF were regarded as corresponding to the changes in rCBFratio, the ratios were compared. Cognitive function was also evaluated and compared.

RESULTS

We found that the rCBFratio changed with an average range of 11.5% during WBV exercise, and similar changes were observed after 24-week WBV training with a 13.0% change, resulting in improved cognitive function (MoCA-J, P = 0.028). The rCBFratio increased in the parietal association cortex and occipital lobes, including the precuneus and posterior cingulate gyrus, at which hypoperfusion was detected at baseline, but decreased in the frontal lobe and anterior cingulate gyrus. The rCBFratio increased on the right side of several motion-suppressive nuclei by WBV exercise; the bilateral red nuclei and right medial globus pallidus by WBV training.

CONCLUSION

WBV exercise and training increase rCBF in aMCI patients, and WBV training enhances cognitive function and may increase the cognitive reserve. Further investigation is necessary.

Effect of different parietal hypoperfusion on neuropsychological characteristics in mild cognitive impairment

BACKGROUND

In early-stage amnestic mild cognitive impairment (aMCI), differences in the neuropsychological characteristics of each individual are subtle. We investigated differences in neuropsychological performance between aMCI patients with and without hypoperfusion in the medial parietal regions (MP). We further compared patients with hypoperfusion in the left and right lateral parietal regions.

METHODS

We examined 165 aMCI patients (mean age: 76.8 ± 5.5 years; 87 women) who had undergone neuropsychological measurement and single-photon emission computed tomography. We classified participants into two subgroups with and without hypoperfusion: MP hypoperfusion (+) and MP hypoperfusion (-); classification was based on Z-scores (calculated by three-dimensional stereotactic surface projection technique) of three regions of interest in the parietal lobes (i.e. MP regions including posterior cingulate cortex and precuneus and left and right inferior parietal lobules (lateral parietal regions)). The MP hypoperfusion (-) group was classified into left lateral parietal hypoperfusion (+) and right lateral parietal hypoperfusion (+) subgroups. We performed either univariate or multivariate ancova to compare neuropsychological scores for continuous variables between groups and examined dichotomous variables using χ² tests.

RESULTS

In the overall aMCI sample, scores on logical memory delayed recall in the MP hypoperfusion (+) group were significantly lower than those in the MP hypoperfusion (-) group. Total scores on Rey-Osterrieth Complex Figure Test delayed recall were also marginally lower in the MP hypoperfusion (+) group than in the MP hypoperfusion (-) group. Comparisons of neuropsychological test scores between the left and right lateral parietal hypoperfusion (+) groups revealed no significant differences.

CONCLUSIONS

The present findings suggest that MP hypoperfusion (+) is associated with more robust memory deficits than MP hypoperfusion (-). Combining neuropsychological tests and single-photon emission computed tomography findings may be useful for early detection of cognitive decline in aMCI.

The combination of MMSE with VSRAD and eZIS has greater accuracy for discriminating mild cognitive impairment from early Alzheimer's disease than MMSE alone

Background

Alzheimer’s disease (AD) is assessed by carefully examining a patient’s cognitive impairment. However, previous studies reported inadequate diagnostic accuracy for dementia in primary care settings. Many hospitals use the automated quantitative evaluation method known as the Voxel-based Specific Regional Analysis System for Alzheimer’s Disease (VSRAD), wherein brain MRI data are used to evaluate brain morphological abnormalities associated with AD. Similarly, an automated quantitative evaluation application called the easy Z-score imaging system (eZIS), which uses brain SPECT data to detect regional cerebral blood flow decreases associated with AD, is widely used. These applications have several indicators, each of which is known to correlate with the degree of AD. However, it is not completely known whether these indicators work better when used in combination in real-world clinical practice.

Methods

We included 112 participants with mild cognitive impairment (MCI) and 128 participants with early AD in this study. All participants underwent MRI, SPECT, and the Mini-Mental State Examination (MMSE). Demographic and clinical characteristics were assessed by univariate analysis, and logistic regression analysis with a combination of MMSE, VSRAD and eZIS indicators was performed to verify whether the diagnostic accuracy in discriminating between MCI and early AD was improved.

Results

The area under the receiver operating characteristic curve (AUC) for the MMSE score alone was 0.835. The AUC was significantly improved to 0.870 by combining the MMSE score with two quantitative indicators from the VSRAD and eZIS that assessed the extent of brain abnormalities.

Conclusion

Compared with the MMSE score alone, the combination of the MMSE score with the VSRAD and eZIS indicators significantly improves the accuracy of discrimination between patients with MCI and early AD. Implementing VSRAD and eZIS does not require professional clinical experience in the treatment of dementia. Therefore, the accuracy of dementia diagnosis by physicians may easily be improved in real-world primary care settings.

Diagnostic utility and characteristics of CT-based attenuation correction in brain perfusion SPECT/CT in predicting the exacerbation of Alzheimer changes from mild cognitive impairment utilizing voxel-based statistical analysis in comparison with Chang's method

OBJECTIVE

We examined the diagnostic value of brain perfusion single-photon emission computed tomography (SPECT) using voxel-based statistical analysis with CT-based attenuation correction (CT-AC) by comparing it to that with Chang's AC in mild cognitive impairment (MCI) patients and attempted to locate brain areas that are good indicators predicting the progression of MCI.

METHODS

Twenty-six individuals matched for age, educational background and initial Mini-Mental State Examination (MMSE) score of more than 24 underwent SPECT with N-isopropyl-4-[¹²³I]iodoamphetamine and were assigned to 2 groups: the stable MCI (S-MCI) group comprising 11 subjects who maintained their MMSE score (mean 27.0) during at least a 1-year follow-up period (mean 37.2 months) and the progressive MCI (P-MCI) group comprising 15 subjects whose MMSE scores decreased by 3 or more points (from 26.4 to 21.4, mean). The diagnostic values of the two AC methods for discriminating P-MCI from S-MCI were compared using voxel-based statistical analysis in the lobe (Level 2) and lobule/gyrus levels (Level 3).

RESULTS

Receiver operating characteristic analysis revealed that the area under the curve (AUC) was higher with CT-AC than with Chang's AC in the left temporal and limbic lobes in Level 2. In Level 3, the AUC in the left middle temporal gyrus was higher with CT-AC (0.852) than with Chang's AC (0.827). There were differences between the gyri/lobules that showed higher AUCs with CT-AC and those that showed higher AUCs with Chang's AC. When the gyri with the 4 highest AUCs were combined, AUC (0.897) and accuracy (84.6%) were better with CT-AC than with Chang's AC (0.806 and 80.8%). Surprisingly, the AUCs in the posterior cingulate gyrus and precuneus, excluding the AUC in the right precuneus with Chang's AC (0.715), were no more than 0.70 and less useful.

CONCLUSIONS

CT-AC may allow brain perfusion SPECT to reflect more exact neuropathic changes in MCI that would cause progression of early AD. CT-AC in conjunction with voxel-based statistical analysis could possess higher diagnostic accuracy for exacerbation of disease implying early Alzheimer changes in MCI patients, with decreases in cerebral perfusion in the left temporal and limbic lobes representing good indicators.

The Supplementary Motor Area Responsible for Word Retrieval Decline After Acute Thalamic Stroke Revealed by Coupled SPECT and Near-Infrared Spectroscopy

Damage to the thalamus may affect cognition and language, but the underlying mechanism remains unknown. In particular, it remains a riddle why thalamic aphasia occasionally occurs and then mostly recovers to some degree. To explore the mechanism of the affected cognition and language, we used two neuroimaging techniques—single-photon emission computed tomography (SPECT), suitable for viewing the affected brain distribution after acute thalamic stroke, and functional near-infrared spectroscopy (f-NIRS), focusing on hemodynamic responses of the supplementary motor area (SMA) responsible for speech production in conjunction with the frontal aslant tract (FAT) pathway. SPECT yielded common perfusion abnormalities not only in the fronto–parieto–cerebellar loop, but also in the SMA, IFG and surrounding language-relevant regions. In NIRS sessions during a phonemic verbal fluency task, we found significant word retrieval decline in acute thalamic patients relative to age-matched healthy volunteers. Further, NIRS showed strong correlation between word retrieval and posterior SMA responses. In addition, follow-up NIRS exhibited increased bilateral SMA responses linked to improving word retrieval ability. The findings suggest that cognitive dysfunction may be related to the fronto–parieto–cerebellar loop, while language dysfunction is attributed to the SMA, IFG and language-related brain areas. SMA may contribute to the recovery of word retrieval difficulty and aphasia after thalamic stroke.

Relationship between decreased cerebral blood flow and amnesia after microsurgery for anterior communicating artery aneurysm

Objective

Postoperative amnesia after surgery for anterior communicating artery aneurysm might be associated with the damage of the basal forebrain. Our purpose was to verify whether decreased regional cerebral blood flow (rCBF) in basal forebrain could be related to the degree of postoperative amnesia.

Methods

Regional voxel rCBF data analyzed using three-dimensional stereotactic surface projection on ¹²³I-IMP-SPECT were compared between ten patients with postoperative amnesia and 13 normal subjects. The Severity (average Z score of the voxels with a Z score that exceeds a threshold value of 2) was calculated. The cerebral lobes with rCBF exhibiting Severity > 2 in all patients were identified. In these lobes, we then examined whether there was a gyrus exhibiting Severity that was negatively related to memory quotients (MQs).

Results

In the right subcallosal gyrus, there was a significant negative correlation between Severity and visual MQ (ρ= −  0.884, p = 0.0007) or general MQ (ρ =− 0.853, p = 0.0017). In the right anterior cingulate gyrus, there was a significant negative correlation between Severity and verbal MQ (ρ = − 0.769, p = 0.0092). In the right rectal gyrus, there was a significant negative correlation between Severity and general MQ (ρ =  −  0.811, p = 0.0044). No significant correlations were found between Severity in other brain regions and verbal, visual, or general MQ.

Conclusions

The decreased rCBF in the subcallosal gyrus included in the basal forebrain, anterior cingulate gyrus, and the rectal gyrus in the right hemisphere was related to postoperative amnesia.

Electronic supplementary material

The online version of this article (10.1007/s12149-020-01436-z) contains supplementary material, which is available to authorized users.

Differences in cerebellar perfusion between Parkinson's disease and multiple system atrophy

INTRODUCTION

Objective biomarkers are required for differential diagnosis of Parkinson's disease (PD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP).

OBJECTIVE

We aimed to determine if cerebellar blood flow, measured using N-isopropyl-[¹²³I] p-iodoamphetamine single photon emission computed tomography (¹²³I -IMP-SPECT), was useful for differentiating between PD, MSA and PSP.

METHODS

Twenty-four patients with PD, seventeen patients with MSA with predominant parkinsonian features (MSA-P), sixteenth patients with MSA with predominant cerebellar ataxia (MSA-C) and eight patients with PSP were enrolled. Twenty-seven normal controls' data were used for the calculation of z score. All patients underwent ¹²³I -IMP-SPECT, and data were analyzed using a three-dimensional-stereotactic surface projection program.

RESULTS

Cerebellar perfusion in MSA-P (MSA-P vs PD, P = .002; MSA-P vs PSP, P < .001) and MSA-C (MSA-C vs PD, P < .001; MSA-C vs PSP, P < .001) were significantly decreased compared with PD or PSP. There was no significant difference in perfusion between PD and PSP groups (P = .061). The area under the receiver operating characteristic curve for cerebellar perfusion between MSA-P and PD was 0.858.

CONCLUSION

Our findings revealed that cerebellar perfusion by ¹²³I-IMP-SPECT was useful for differentiating between PD and MSA-P.

Selective neuronal damage and blood pressure in atherosclerotic major cerebral artery disease

OBJECTIVE

In patients with atherosclerotic major cerebral artery disease, low blood pressure might impair cerebral perfusion, thereby exacerbate the risk of selective neuronal damage. The purpose of this retrospective study was to determine whether low blood pressure at follow-up is associated with increased selective neuronal damage.

METHODS

We retrospectively analysed data from 76 medically treated patients with atherosclerotic internal carotid artery or middle cerebral artery disease with no ischaemic episodes on a follow-up of 6 months or more. All patients had measurements of the distribution of central benzodiazepine receptors twice using positron emission tomography and ¹¹C-flumazenil. Using three-dimensional stereotactic surface projections, we quantified abnormal decreases in the benzodiazepine receptors of the cerebral cortex within the middle cerebral artery distribution and correlated these changes in the benzodiazepine receptors index with blood pressure values at follow-up examinations.

RESULTS

The changes in the benzodiazepine receptor index during follow-up (mean 27±21 months) were negatively correlated with systolic blood pressure at follow-up. The relationship between changes in benzodiazepine receptor index and systolic blood pressure was different among patients with and without decreased cerebral blood flow at baseline (interaction, p<0.005). Larger increases in benzodiazepine receptor index (neuronal damage) were observed at lower systolic blood pressure levels in patients with decreased cerebral blood flow than in patients without such decreases.

CONCLUSION

In patients without ischaemic stroke episodes at follow-up but with decreased cerebral blood flow due to arterial disease, low systolic blood pressure at follow-up may be associated with increased selective neuronal damage.

Can we predict amyloid deposition by objective cognition and regional cerebral blood flow in patients with subjective cognitive decline?

BACKGROUND

Subjective cognitive decline (SCD) may herald the first symptoms of Alzheimer's disease (AD) whereas individuals with beta-amyloid (Aβ) deposition are regarded as a high-risk group for AD. Recently, amyloid positron emission tomography (PET) studies have demonstrated clinical and cognitive feature differences between Aβ-positive and negative SCD, but details of their differences remain unclear. We aimed to investigate the relationships among Aβ deposition, clinical, and cognitive features in patients with SCD.

METHODS

Forty-two patients with SCD (22 women, 74.5 ± 4.7 years) were examined using fluorine-18 florbetaben PET and were divided into Aβ-positive (n = 10) and negative (n = 32) groups. We compared cognitive and psychological outcomes, and single photon emission computed tomography (SPECT) imaging data between the two groups. In addition, a linear regression analysis was performed to assess relationships between the severity of SCD and neuropsychological tests, affective scores, and demographic factors.

RESULTS

The rate of score changes from the immediate recall to delayed recall in the logical memory subtest of the Wechsler's Memory Scale Revised were different between the groups (P = 0.04). However, the binary logistic regression analysis showed no significant differences between the two. In addition, the severity of SCD was significantly strong in women (P = 0.002). Furthermore, within the Aβ-negative group, subjective memory loss correlated with word fluency category score (P = 0.023) and apathy scale (P = 0.037).

CONCLUSIONS

No significant differences were observed between Aβ-positive and -negative SCD on any of the neuropsychological measures, clinical measures, or SPECT imaging. Further, the severity of SCD was not predicted by the symptoms of anxiety, depression, or neuropsychological examination.

The Cingulate Island Sign on FDG-PET vs. IMP-SPECT to Assess Mild Cognitive Impairment in Alzheimer's Disease vs. Dementia with Lewy Bodies

BACKGROUND AND PURPOSE

The cingulate island sign (CIS) on ¹⁸ F-fluorodeoxyglucose positron emission tomography (FDG-PET); ie, the relative preservation of mid-posterior cingulate cortex metabolism, is a supportive biomarker in the diagnostic criteria for dementia with Lewy bodies (DLB). However, limited information is currently available on the diagnostic value of the CIS on FDG-PET or ¹²³ I-iodoamphetamine single-photon emission computed tomography (IMP-SPECT) for differentiating between mild cognitive impairment (MCI) due to Alzheimer's disease (AD) (MCI-AD) and MCI due to DLB (MCI-DLB).

METHODS

We examined the CIS ratio in 9 AD patients, 9 DLB patients, 8 patients with MCI-AD, and 9 patients with MCI-DLB using FDG-PET and IMP-SPECT. The CIS ratio was calculated using NEUROSTAT software.

RESULTS

In the dementia groups, a receiver operating characteristic analysis of the CIS ratio showed significant accuracy for differentiating between AD and DLB on FDG-PET and IMP-SPECT. In the MCI groups, only the FDG-PET derived CIS ratio displayed significant accuracy for differentiating between AD and DLB.

CONCLUSIONS

The FDG-PET and IMP-SPECT derived CIS ratios are both useful for differentiating between AD and DLB. The FDG-PET derived CIS ratio is more valuable than the IMP-SPECT derived CIS ratio for differential diagnosis in patients with MCI. A larger study is needed to confirm these results.

rCBF and cognitive impairment changes assessed by SPECT and ADAS-cog in late-onset Alzheimer's disease after 18 months of treatment with the cholinesterase inhibitors donepezil or galantamine

Late-onset Alzheimer's disease (AD) differs substantially from early-onset AD. In this cross sectional study we investigated brain perfusion changes after 18 months of treatment with cholinesterase inhibitors (ChEIs) donepezil or galantamine. Twenty-five drug-naïve late-onset AD patients were recruited from outpatient clinics. We examined brain perfusion using single photon emission computed tomography (SPECT) and used three-dimensional stereotactic surface projection (3D-SSP) and the stereotactic extraction estimation method (SEE) level 3 to analyze classified gyrus level segments. We assessed cognitive function using the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) grouped into three subgroup domains, language, memory, and praxis. In the follow-up data, some regions were further hypoperfused, reflecting worsening of the disease, while other regions showed alleviated hypoperfusion, potentially related to the ChEIs treatment. Regional cerebral blood flow (rCBF) decreased in the parietal cortex and increased in the frontal and the limbic cortices. Increased hypoperfusion significantly correlated with ADAS-cog scores changes were seen in the superior parietal lobule, inferior parietal lobule, angular gyrus, and supramarginal gyrus of the parietal cortex. Alleviated hypoperfusion significantly related to recovery of ADAS-cog scores were seen in the rectal and paracentral lobule of the frontal cortex, and the anterior cingulate of the limbic cortex. These regions showed significant relationships with total ADAS-cog and language, memory and praxis subscales scores. The current longitudinal study indicates prominent rCBF changes and their relationships with changes in ADAS-cog scores in late-onset AD patients.

Motor Improvement-Related Regional Cerebral Blood Flow Changes in Parkinson's Disease in Response to Antiparkinsonian Drugs

Little is known about the relationship between regional cerebral blood flow (rCBF) change and clinical improvement in patients with Parkinson's disease (PD). Single-photon emission computed tomography (SPECT) measurement of cerebral blood flow allows evaluation of temporal changes in brain function, and using SPECT, we aimed to identify motor improvement-related rCBF changes in response to the administration of antiparkinsonian drugs. Thirty PD patients (16 without dementia; 14 with dementia) were scanned with technetium-99m labeled ethyl cysteinate dimer SPECT and were rated with the Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III, both before and after a single administration of antiparkinsonian drugs. The SPECT data were processed using Statistical Parametric Mapping 2, the easy Z-score Imaging System, and voxel-based Stereotactic Extraction Estimation. The rCBF responses in the deep brain structures after administration of antiparkinsonian drugs tended to be larger than those in cortical areas. Among these deep brain structures, the rCBF increases in the substantia nigra (SN), lateral geniculate (LG) body, and medial geniculate (MG) body correlated with drug efficacy (p < 0.05, respectively). A subgroup analysis revealed that the motor improvement-related rCBF change in the MG was statistically significant, irrespective of cognitive function, but the significant changes in the LG and SN were not found in subjects with dementia. In conclusion, our SPECT study clearly exhibited drug-driven rCBF changes in PD patients, and we newly identified motor improvement-related rCBF changes in the LG and MG. These results suggest that rCBF changes in these regions could be considered as candidates for clinical indicators for objective evaluation of disease progression. Furthermore, functional studies focusing on the LG and MG, especially in relation to therapies using audio-visual stimuli, may bring some new clues to explain the pathophysiology of PD.

Age-related increase in GABAA receptor distribution in the prefrontal cortex

Profound insight into age-related changes in γ-aminobutyric acid type A receptor (GABAA-R) distribution using iodine-123-iomazenil single photon emission computed tomography (IMZ-SPECT) can contribute to accurate in vivo evaluation. We evaluated the age-related changes in prefrontal cortex (PFC), which is the key region involved in various neurological and psychiatric diseases. In this study, IMZ-SPECT imaging data of 21 healthy males with an age range of 22-59 (mean, 38 ± 12) years were analyzed using three-dimensional stereotactic surface projection (3D-SSP). The Z-score images of the younger group (age < 40, n = 11) and the older group (age ≥ 40, n = 10) were compared. Subsequently, the mean RI-count ratios calculated for each Brodmann area (BA) by stereotactic extraction estimation method were compared between these groups. Thereafter, linear regression analysis between age and RI-count ratio was performed for all enrolled subjects. In the result, IMZ accumulation increased in bilateral BA10, 11, and the BA47 (left hemisphere) in the older group compared with the younger group. Furthermore, regression analysis demonstrated a significant positive correlation between age and RI-count ratio in these areas. Our findings indicate that GABAA-R distribution in the PFC relatively increases with age. Therefore, we concluded that the age-related changes should be considered to accurately evaluate pathophysiology of neurological and psychiatric diseases.

Usefulness of the convexity apparent hyperperfusion sign in 123I-iodoamphetamine brain perfusion SPECT for the diagnosis of idiopathic normal pressure hydrocephalus

OBJECTIVE

The gold standard for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is the CSF removal test. For elderly patients, however, a less invasive diagnostic method is required. On MRI, high-convexity tightness was reported to be an important finding for the diagnosis of iNPH. On SPECT, patients with iNPH often show hyperperfusion of the high-convexity area. The authors tested 2 hypotheses regarding the SPECT finding: 1) it is relative hyperperfusion reflecting the increased gray matter density of the convexity, and 2) it is useful for the diagnosis of iNPH. The authors termed the SPECT finding the convexity apparent hyperperfusion (CAPPAH) sign.

METHODS

Two clinical studies were conducted. In study 1, SPECT was performed for 20 patients suspected of having iNPH, and regional cerebral blood flow (rCBF) of the high-convexity area was examined using quantitative analysis. Clinical differences between patients with the CAPPAH sign (CAP) and those without it (NCAP) were also compared. In study 2, the CAPPAH sign was retrospectively assessed in 30 patients with iNPH and 19 healthy controls using SPECT images and 3D stereotactic surface projection.

RESULTS

In study 1, rCBF of the high-convexity area of the CAP group was calculated as 35.2–43.7 ml/min/100 g, which is not higher than normal values of rCBF determined by SPECT. The NCAP group showed lower cognitive function and weaker responses to the removal of CSF than the CAP group. In study 2, the CAPPAH sign was positive only in patients with iNPH (24/30) and not in controls (sensitivity 80%, specificity 100%). The coincidence rate between tight high convexity on MRI and the CAPPAH sign was very high (28/30).

CONCLUSIONS

Patients with iNPH showed hyperperfusion of the high-convexity area on SPECT; however, the presence of the CAPPAH sign did not indicate real hyperperfusion of rCBF in the high-convexity area. The authors speculated that patients with iNPH without the CAPPAH sign, despite showing tight high convexity on MRI, might have comorbidities such as Alzheimer’s disease.

Vascular risk factors and the relationships between cognitive impairment and hypoperfusion in late-onset Alzheimer's disease

OBJECTIVE

Our recent single-photon emission computed tomography (SPECT) study of patients with late-onset Alzheimer's disease (AD) revealed that regional cerebral blood flow (rCBF) was reduced in the frontal, temporal, and limbic lobes, and to a lesser degree in the parietal and occipital lobes. Moreover, these patients' scores on the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) were significantly correlated with rCBF in some gyri of the frontal, parietal, and limbic lobes. Our present study aimed to understand how vascular factors and metabolic disease influenced the relationship between rCBF and ADAS-cog scores.

METHODS

We divided late-onset AD patients into two groups according to their Hachinski Ischemic Score (HIS), low vascular risk patients had values of ≤4 (n=25) and high vascular risk patients had scores ≥5 (n=15). We examined rCBF using brain perfusion SPECT data.

RESULTS

The degrees and patterns of reduced rCBF were largely similar between late-onset AD patients in both groups, regardless of HIS values. Cognitive function was significantly associated with rCBF among late-onset AD patients with low vascular risk (HIS≤4), but not among those with high vascular risk (HIS≥5). Furthermore, metabolic diseases, such as hypertension and diabetes mellitus, disrupted the relationships between hypoperfusion and cognitive impairments in late-onset AD patients.

CONCLUSION

Factors other than hypoperfusion, such as hypertension and diabetes mellitus, could be involved in the cognitive dysfunction of late-onset AD patients with high vascular risk.

Working memory deficit in drug-resistant epilepsy with an amygdala lesion

This study compared temporal lobe epilepsy (TLE) patients with amygdala lesion (AL) without hippocampal sclerosis (HS) (TLE-AL) with patients with TLE and HS without AL (TLE-HS). Both subtypes of TLE arose from the right hemisphere.

The TLE-AL group exhibited a lower Working Memory Index (WMI) on the Wechsler Adult Intelligence Scale, third edition (WAIS-III), indicating that the amygdala in the right hemisphere is involved in memory-related function. [18F]fluorodeoxyglucose positron emission topography (FDG-PET) showed glucose hypometabolism limited to the right uncus for the TLE-AL group.

The results suggest the importance of considering cognitive functions in the non-dominant hemisphere to prevent impairment after surgery.

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Low working memory index (WMI) was found due to a right amygdala lesion (AL).

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Glucose hypometabolism was limited to the right uncus for the Temporal Lobe Epilepsy-AL (TLE-AL) patients

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Glucose hypometabolism was associated with low WMI in the TLE-AL patients

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We suggest the need to consider cognitive function in non-dominant hemisphere

Reduced CBF recovery detected by longitudinal 3D-SSP SPECT analyses predicts outcome of postoperative patients after subarachnoid haemorrhage

The aim of this study was to evaluate the impact of cerebral blood flow (CBF) recovery obtained from brain single-photon emission computed tomography (SPECT) images on postoperative outcome after aneurysmal subarachnoid haemorrhage (SAH). Twenty-nine patients who had undergone surgical clipping for ruptured anterior communicating artery aneurysms were analyzed prospectively. Routine measurements of CBF were performed using technetium-99 m hexamethyl propyleneamine oxine SPECT on days 4 and 14 after SAH. Regional voxel data analyzed by three dimensional stereotactic surface projection (3D-SSP) were compared between patients and age-matched normal database (NDB). In 3D-SSP analysis of all patients, cortical hypoperfusion around the surgical site in bilateral frontal lobes was evident on day 4 (P < .05 vs NDB), which was improved significantly on day 14. However, the recovery was less complete in patients with poor clinical grades (P < .05) and presenting symptoms attributable to delayed cerebral ischaemia (DCI) (P < .05) than those without. Multivariate analysis showed that patients with mild to moderate CBF recovery (relative Z-score differences of <4) (P = .014; odds ratio, 2.5; 95% confidence interval, 1.93-3.31) was independently associated with poor functional outcome at 3 months. We conclude that reduced CBF recovery detected by serial 3D-SSP SPECT image analyses can be a potential predictor of poor prognosis in postoperative patients after SAH.

Cingulate island sign temporally changes in dementia with Lewy bodies

The cingulate island sign (CIS) that reflects sparing of the posterior cingulate cortex (PCC) relative to the precuneus plus cuneus on FDG-PET and brain perfusion SPECT, has been proposed as a feature of dementia with Lewy bodies (DLB). As the CIS is influenced by concomitant Alzheimer's disease (AD)-type neurofibrillary tangle (NFT) pathology, we postulated that the CIS gradually disappears as DLB progresses. To determine temporal changes in the CIS, 24 patients with mild DLB and 7 with prodromal DLB underwent ¹²³I-IMP-SPECT and MMSE twice at an interval of two years. The CIS was evaluated as a ratio that was derived by dividing IMP accumulation in the PCC with that in the precuneus plus cuneus. We found that the CIS changed over time and that the relationship between CIS ratios and MMSE scores was inverted U-shaped. Thus, the CIS was most obvious in the vicinity of an MMSE score of 22 and it gradually diminished as the MMSE score decreased. Moreover, a lower CIS ratio in mild DLB was associated with a worse prognosis for cognitive decline, presumably due to concomitant AD-type NFT pathology. Our findings would provide a foundation for the appropriate usage of CIS as a biomarker.

Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer’s disease and depression

AIM

To evaluate usefulness of single photon emission computed tomography (SPECT) with three-dimensional stereotactic surface projection (3D-SSP) in distinguishing between Alzheimer’s disease (AD) and depression.

METHODS

We studied 43 patients who presented with both depressive symptoms and memory disturbance. Each subject was evaluated using the following: (1) the Minimal Mental State Examination; (2) the Hamilton Rating Scale for Depression; (3) Clinical Global Impression-Severity scale (CGI-S); and (4) SPECT imaging with 3D-SSP.

RESULTS

The MMSE scores correlated significantly with the maximum Z-scores of AD-associated regions. CGI-S scores correlated significantly with the maximum Z-scores of depression-associated regions. Factor analysis identified three significant factors. Of these, Factor 1 could be interpreted as favouring a tendency for AD, Factor 2 as favouring a tendency for pseudo-dementia, and Factor 3 as favouring a depressive tendency.

CONCLUSION

We investigated whether these patients could be categorized as types: Type A (true AD), Type B (pseudo-dementia), Type C (occult AD), and Type D (true depression). The factor scores in factor analysis supported the validity of this classification. Our results suggest that SPECT with 3D-SSP is highly useful for distinguishing between depression and depressed mood in the early stage of AD.

Regional cerebral glucose metabolism in systemic lupus erythematosus patients with major depressive disorder

OBJECTIVES

Depression is frequently observed in patients with systemic lupus erythematosus (SLE). Neuropsychiatric SLE (NPSLE) patients often exhibit cerebral hypometabolism, but the association between cerebral metabolism and depression remains unclear. To elucidate the features of cerebral metabolism in SLE patients with depression, we performed brain 18F-fluoro-d-glucose positron emission tomography (FDG-PET) on SLE patients with and without major depressive disorder.

METHODS

We performed brain FDG-PET on 20 SLE subjects (5 male, 15 female). The subjects were divided into two groups: subjects with major depressive disorder (DSLE) and subjects without major depressive disorder (non-DSLE). Cerebral glucose metabolism was analyzed using the three-dimensional stereotactic surface projection (3D-SSP) program. Regional metabolism was evaluated by stereotactic extraction estimation (SEE), in which the whole brain was divided into segments.

RESULTS

Every SLE subject exhibited cerebral hypometabolism, in contrast to the normal healthy subjects. Regional analysis revealed a significantly lower ER in the left medial frontal gyrus (p=0.0055) and the right medial frontal gyrus (p=0.0022) in the DSLE group than in the non-DSLE group.

CONCLUSION

Hypometabolism in the medial frontal gyrus may be related to major depressive disorder in SLE. Larger studies are needed to clarify this relationship.

Relationships between cognitive impairment on ADAS-cog and regional cerebral blood flow using SPECT in late-onset Alzheimer's disease

The aim of this study was to examine brain hypoperfusion and its relationship with cognitive dysfunction in late-onset Alzheimer's disease (AD). Forty patients with late-onset AD and not receiving acetylcholinesterase inhibitors were recruited from outpatient clinics. We examined cognitive function using the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and brain perfusion using single-photon emission computed tomography, and analyzed classified gyrus level segments with three-dimensional stereotactic surface projection and the stereotactic extraction estimation method level 3. ADAS-cog subscales were grouped into three domains: language, memory, and praxis. Patients with late-onset AD showed an apparent reduction in regional cerebral blood flow (rCBF) with a z score >1.5 in the frontal, temporal, and limbic lobes, with lesser reduction in the parietal and occipital lobes. Although hypoperfusion in the orbital, rectal, and subcallosal gyri of the frontal lobe was prominent, rCBF in the inferior frontal gyrus of the frontal lobe was significantly correlated with ADAS-cog total and language and praxis subscale scores. The parahippocampal gyrus of the limbic lobe was also significantly correlated with the ADAS-cog total, language, and praxis subscale scores. Additionally, the cingulate of the limbic lobe was significantly related with ADAS-cog memory. In spite of lesser hypoperfusion, the posterior cingulate gyrus of the limbic lobe was significantly related with ADAS-cog total, language, and memory subscale scores. Further, each subdivision of ADAS-cog was found to be related with various brain regions.

Pure Amorphagnosia without Tactile Object Agnosia

A 54-year-old female showed amorphagnosia without ahylognosia and tactile agnosia 40 days after the onset of right cerebral infarction. Her basic somatosensory functions were normal. The appreciation of substance qualities (hylognosia) was preserved, but the patient's inability to recognize the size and shape (morphagnosia) was confined to 2- and 3-dimensional shapes (amorphagnosia) in the left hand. However, the patient's ability to recognize real daily objects was well preserved. Brain MRI after admission showed ischemic lesions confined to the right pre- and postcentral gyri and the medial frontal cortex on DWI and FLAIR images. An analysis of SPECT images revealed that the most decreased areas were localized to the pre- and postcentral gyri, superior and inferior parietal lobules, supramarginal gyrus, and angular gyrus. Considering the previous reported cases, the responsible lesion for the impaired perception of hylognosia and morphagnosia may not necessarily be confined to the right hemisphere. To date, 5 reports (6 cases) of tactile agnosia have been published; 4 cases presented with both ahylognosia and amorphagnosia, while 1 presented with only amorphagnosia, and another showed amorphagnosia and mild ahylognosia. Our case is the first to present with only amorphagnosia without tactile agnosia. The mechanism for the well-preserved recognition of real objects may depend on the preserved hylognosia. Of note, there have been no reports showing only ahylognosia without amorphagnosia. Further studies are necessary to clarify whether or not patients with preserved hylognosia or morphagnosia retain the ability to perceive real objects.

Progressive Cortical Neuronal Damage and Extracranial-Intracranial Bypass Surgery in Patients with Misery Perfusion

BACKGROUND AND PURPOSE

Misery perfusion may cause selective neuronal damage in atherosclerotic ICA or MCA disease. Bypass surgery can improve misery perfusion and may prevent neuronal damage. On the other hand, surgery conveys a risk for neuronal damage. The purpose of this retrospective study was to determine whether progression of cortical neuronal damage in surgically treated patients with misery perfusion is larger than that in surgically treated patients without misery perfusion or medically treated patients with misery perfusion.

MATERIALS AND METHODS

We evaluated the distribution of benzodiazepine receptors twice by using PET and ¹¹C-labeled flumazenil in 18 surgically treated patients with atherosclerotic ICA or MCA disease (9 with misery perfusion and 9 without) and no perioperative stroke before and after bypass surgery; in 8 medically treated patients with misery perfusion and no intervening ischemic event; and in 7 healthy controls. We quantified abnormal decreases in the benzodiazepine receptors of the cerebral cortex within the MCA distribution and compared changes in the benzodiazepine receptor index among the 3 groups.

RESULTS

The change in the benzodiazepine receptor index in surgically treated patients with misery perfusion (27.5 ± 15.6) during 7 ± 5 months was significantly larger than that in surgically treated patients without misery perfusion (-5.2 ± 9.4) during 6 ± 4 months (P < .001) and in medically treated patients with misery perfusion (3.2 ± 15.4) during 16 ± 6 months (P < .01).

CONCLUSIONS

Progression of cortical neuronal damage in surgically treated patients with misery perfusion and no perioperative stroke may occur and may be larger than that in medically treated patients with misery perfusion and no intervening ischemic event.

Regional glucose hypometabolic spread within the primary motor cortex is associated with amyotrophic lateral sclerosis disease progression: A fluoro-deoxyglucose positron emission tomography study

Objective

Here we investigate the process of neurodegeneration in amyotrophic lateral sclerosis (ALS). The relationship between the cortical field spreading of glucose metabolic decreases in the primary motor cortex (PMC) and the progression of corresponding extremity dysfunction was evaluated using [¹⁸F] fluoro-deoxyglucose (FDG)-positron emission tomography (PET).

Methods

Patients with ALS underwent [¹⁸F] FDG-PET and the resulting datasets were individually contrasted against healthy controls using the NEUROSTAT software. The extent ratio was defined as the proportion of pixels with a significant Z-score decrease within regions of the primary motor cortex (precentral gyrus or paracentral lobule) opposite to the impaired upper extremities (UEs) or lower extremities (LEs), respectively. Clinical symptoms in all extremities were assessed using an upper motor neuron (UMN) score and the MRC (Medical Research Council) sum score upon physical examination. Cross-sectional correlations were analysed between clinical symptoms, the duration of these symptoms, and the extent ratio.

Results

Nineteen regions of the primary motor cortex corresponding to symptomatic limb in 10 participants were evaluated. In the corresponding region of the primary motor cortex, the extent ratio increased (same meaning as hypometabolic area spread) in association with symptom duration (r_s = 0.5, p = 0.03). Neither UMN nor lower motor neuron (LMN) scores were correlated with symptom duration. Three out of 19 impaired regions did not show upper motor neuron (UMN) signs upon physical examination. The extent ratio and UMN score-controlled symptom duration were partially correlated (r_s = 0.5, p = 0.05).

Conclusions

In patients with ALS, glucose metabolism decreased in the impaired side of the primary motor cortex depending on the clinical symptom progression in the corresponding extremities, regardless of the presence of clinical UMN signs. A decrement in glucose metabolism on FDG-PET corresponding to symptoms in the primary motor cortex might be an indicator of the time-dependent course of ALS neurodegeneration.

Diagnosis of dementia with Lewy bodies: can 123I-IMP and 123I-MIBG scintigraphy yield new core features?

OBJECTIVE

Since the clinical symptoms of different types of dementia frequently overlap, especially in the earlier stages at onset, it is difficult to distinguish dementia with Lewy bodies (DLB) from other neurodegenerative dementias based on their clinical manifestations alone. Nuclear medicine imaging has been reported as a high-value index for the objective evaluation and diagnosis of DLB. The aim of this study was to evaluate whether nuclear medicine imaging findings may yield core features to be added to the diagnosis of DLB.

METHODS

We enrolled 332 patients with suspected DLB. All were evaluated by both ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) myocardial scintigraphy and ¹²³I-labelled N-isopropyl-p-iodoamphetamine (¹²³I-IMP). brain perfusion single-photon emission CT. The final clinical diagnosis indicated probable DLB in 92 patients (40 males, 52 females; mean age ± standard deviation, 77.4 ± 6.4 years; range, 56-89 years); 240 patients (98 males, 142 females; mean age, 75.5 ± 9.0 years; range, 70-87 years) were recorded as being without DLB. The accepted core features used for clinical evaluations were fluctuating cognition, visual hallucinations and Parkinsonism. The nuclear medicine evaluation indices were the severity score of cerebral blood flow on ¹²³I-IMP scintigraphs of the posterior cingulate and praecuneus and a reduction in the blood flow in the occipital lobe. For ¹²³I-MIBG evaluation, we recorded the early and delayed heart-to-mediastinum (H/M) ratios and the washout rate.

RESULTS

Univariate and multivariate analyses of fluctuating cognition, visual hallucinations, Parkinsonism and early H/M ratio in patients with probable and without DLB revealed significant differences. Parameters based on ¹²³I-IMP studies did not show any significant differences by multivariate analysis. The area under the curve for the early H/M ratio was 0.918; for fluctuating cognition, visual hallucinations and Parkinsonism, it was 0.693, 0.760 and 0.611, respectively, by receiver-operating characteristic analysis. The early H/M ratio of <2.0 on ¹²³I-MIBG scintigraphs was of the highest diagnostic accuracy. The sensitivity, specificity and accuracy for the diagnosis of probable DLB were 82.4%, 96.3% and 92.5%, respectively.

CONCLUSION

The early H/M ratio obtained by ¹²³I-MIBG myocardial scintigraphy can serve as a reliable diagnostic index for the core clinical features of DLB. It can be used for the early diagnosis and treatment of DLB. Advances in knowledge: ¹²³I-MIBG myocardial scintigraphy performed at the initial clinical examination can facilitate the early identification or exclusion of DLB and the early H/M ratio may be a diagnostic biomarker for DLB.

123I-FP-CIT SPECT findings and its clinical relevance in prodromal dementia with Lewy bodies

PURPOSE

Evidence for the prodromal stage of dementia with Lewy bodies (DLB) is very limited. To address this issue, we investigate the ¹²³I-FP-CIT SPECT measure of dopamine transporter binding finding and its clinical relevance.

METHODS

We enrolled subjects into a prodromal DLB group (PRD-DLB) (n = 20) and clinical DLB group (CLIN-DLB) (n = 18) and compared these groups with an Alzheimer's disease control group (AD) (n = 10). PRD-DLB was defined as patients having the non-motor symptoms associated with Lewy body disease (LBD) [i.e. REM sleep behavior disorder (RBD), olfactory dysfunction, autonomic dysfunction, and depression] and showing characteristic diffuse occipital hypometabolism in ¹⁸F-FDG PET. CLIN-DLB was defined as patients fulfilling the established criteria of probable DLB. Striatal specific binding ratio (SBR) of ¹²³I-FP-CIT SPECT was used for objective group comparisons. The correlations between SBR and cognitive function (MMSE), motor symptoms (UPDRS3), and duration of LBD-associated non-motor symptoms were compared between the two DLB groups.

RESULTS

Mean SBR scores of both PRD-DLB and CLIN-DLB were significantly lower than those of AD. No correlation was found between SBR and MMSE scores. Both in the CLIN-DLB and total DLB groups, SBR scores were negatively correlated with UPDRS3 scores, whereas no correlation was found in PRD-DLB. Among the LBD-related non-motor symptoms, duration of olfactory dysfunction, and RBD demonstrated negative correlation with SBR scores in PRD-DLB.

CONCLUSION

¹²³I-FP-CIT SPECT may play a role for detecting DLB among the subjects in prodromal stage. During this stage, long-term olfactory dysfunction and/or RBD may indicate more severe degeneration of the nigro-striatal dopaminergic pathway.

Progressive Cortical Neuronal Damage and Chronic Hemodynamic Impairment in Atherosclerotic Major Cerebral Artery Disease

Background and Purpose—

Cross-sectional studies suggest that chronic hemodynamic impairment may cause selective cortical neuronal damage in patients with atherosclerotic internal carotid artery or middle cerebral artery occlusive disease. The purpose of this longitudinal study was to determine whether the progression of cortical neuronal damage, evaluated as a decrease in central benzodiazepine receptors (BZRs), is associated with hemodynamic impairment at baseline or hemodynamic deterioration during follow-up.

Methods—

We evaluated the distribution of BZRs twice using positron emission tomography and 11 C-flumazenil over time in 80 medically treated patients with atherosclerotic internal carotid artery or middle cerebral artery occlusive disease that had no ischemic episodes during follow-up. Using 3D stereotactic surface projections, we quantified abnormal decreases in the BZRs in the cerebral cortex within the middle cerebral artery distribution and correlated changes in the BZR index with the mean hemispheric values of hemodynamic parameters obtained from 15 O gas positron emission tomography.

Results—

In the hemisphere affected by arterial disease, the BZR index in 40 patients (50%) was increased during follow-up (mean 26±20 months). In multivariable logistic regression analyses, increases in the BZR index were associated with the decreased cerebral blood flow at baseline and an increased oxygen extraction fraction during follow-up. Increases in the oxygen extraction fraction during follow-up were associated with a lack of statin use.

Conclusions—

In patients with atherosclerotic internal carotid artery or middle cerebral artery disease, the progression of cortical neuronal damage was associated with hemodynamic impairment at baseline and hemodynamic deterioration during follow-up. Statin use may be beneficial against hemodynamic deterioration and therefore neuroprotective.

Cholinergic enhancement increases regional cerebral blood flow to the posterior cingulate cortex in mild Alzheimer's disease

AIM

The brain region that shows reductions in regional cerebral blood flow (rCBF) earliest is the posterior cingulate cortex (PCC), which is thought to have a relationship with cognitive function. We made a hypothesis that the PCC hypoperfusion is a result of cholinergic dysfunction and can be restored by cholinergic enhancement. This present longitudinal study aimed to detect the restoration of PCC rCBF in response to donepezil, an acetylcholine esterase inhibitor.

METHODS

We evaluated rCBF changes in the PCC, precuneus and anterior cingulate cortex using perfusion single-photon emission computed tomography (SPECT), statistical analysis and region of interest analysis, prospectively. We allocated 36 patients with mild AD to either the responder or non-responder groups based on changes in Mini-Mental State Examination scores. The patients were followed up for 18 months.

RESULTS

The PCC rCBF significantly increased in responders after 6 months of donepezil therapy. Statistical maps at baseline showed a typical decreased pattern of mild AD and obvious rCBF restoration in the bilateral PCC at 6 months in responders. Changes in Mini-Mental State Examination scores and the AD assessment scale cognitive scores significantly correlated with rCBF changes in the PCC of responders.

CONCLUSIONS

Cholinergic enhancement restored PCC rCBF under the three conditions of mild AD, responders and short follow-up interval, and that increase correlated with improved cognitive function. These findings support our hypothesis that PCC rCBF reflects cholinergic function in AD patients. Geriatr Gerontol Int 2017; 17: 951-958.