Search

ABSTRACT Brain disorders including neurological and psychiatric disorders have become a major global public health issue due to their high prevalence and burden. However, elucidating ultimate causes and improving strategies for diagnosis and treatment of these disorders remain challenging due to limited accessibility to living human brain. In addition, there has been a great need for robust biomarkers for them at a very early stage. Neuroimaging technologies have demonstrated the potential in investigating the pathophysiology and developing the biomarkers. The current review discusses the potential diagnostic applications of neuroimaging in brain disorders. We summarized major findings in recent neuroimaging meta-analyses, which could be used as future biomarkers, in Alzheimer's disease, Parkinson's disease, central nervous system inflammation, depression, and schizophrenia. New possibilities of novel imaging techniques were also demonstrated. Finally, future directions for the imaging-based diagnosis were suggested. In spite of promising results from preliminary studies and rapid technological advances, further studies on the reliability and validity of potential imaging biomarkers in larger patient populations and the development of new guidelines for the clinical applications would be required. [ABSTRACT FROM AUTHOR]

ABSTRACT Since both Parkinson's disease with dementia (PDD) and subcortical ischemic vascular dementia (SIVaD) are subcortical dementia syndromes and have similar patterns of cognitive dysfunction, it is difficult to accurately differentiate between these in their early phases using neuropsychological tests. The purpose of this study was to investigate differences in the cerebral perfusion pattern of patients with SIVaD and PDD at the earliest stages using single photon emission computed tomography (SPECT). We, consecutively, recruited 24 patients with mild PDD, 28 patients with mild probable AD, and 33 age-matched healthy subjects. All subjects underwent Tc-99m HMPAO perfusion SPECT and general neuropsychological tests. Brain SPECT images were analyzed using the statistical parametric mapping program. There was more significant hypoperfusion in the right cuneus, fusiform gyrus and lingual gyrus in the occipital lobe, right middle temporal gyrus, right postcentral gyrus, and right cerebellar tonsil in PDD compared with the SIVaD group. Conversely, significant hypoperfusion was observed in the bilateral brain stem, limbic system and posterior cingulate gyrus in SIVaD compared with the PDD group. This study suggests that parieto-occipital hypoperfusion in PDD and hypoperfusion of the brain stem and limbic system in SIVaD are likely useful to differentiate between mild PDD and SIVaD. [ABSTRACT FROM AUTHOR]

ABSTRACT The clinical heterogeneity of Parkinson's disease (PD) is well recognized. It is possible to distinguish two main clinical subgroups, a tremor dominant PD (TP) and nontremor dominant PD (NTP). However studies compared the regional cerebral blood flow between subtypes of PD had rarely been performed yet, although the classification of subtypes was very important because of difference of disease progression and prognosis between subtypes of PD. We recruited 43 patients with PD (21 TP and 22 NTP). All patients with PD underwent brain perfusion SPECT and evaluated motor severity by using the Hoehn and Yahr stage and Part III of the unified Parkinson's disease rating scale (UPDRS). We also compared tremor and nontremor symptoms with motor phenotype scores between two subtypes of PD. Brain perfusion SPECT showed significant hypoperfusion in TP compared with NTP in the left occipital lobe and middle occipital gyrus, left frontal lobe and superior frontal gyrus, cerebellar hemisphere, left lentiform nucleus. On the other hand, brain perfusion SPECT of NTP compared with TP showed hypoperfusion in right parietal lobe and precuneus, left temporal lobe and inferior temporal gyrus, both frontal lobe and inferior frontal gyrus. The present study indicates that pathophysiology of TP compared to NTP has more closely association with neuronal circuits including cerebellar pathway, such as CTC circuit. Therefore, we cautiously assert that neuronal systems other than the nigrostriatal dopaminergic system are likely involved in the generation of tremor in PD. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 222-226, 2013 [ABSTRACT FROM AUTHOR]

It is very difficult that idiopathic Parkinson's disease (PD) patients with dementia (PDD) distinguish from PD patients, because PD patients may exhibit patterns of cognitive impairment. Recently, cardiac I-123 metaiodobenzylguanidine (MIBG) scintigraphy has been used as tools to distinguish PD from atypical parkinsonism. Thus, we performed this study to confirm significant clinical value of cardiac I-123 MIBG scintigraphy for differential diagnosis between PD and PDD. Cardiac I-123 MIBG scintigraphy was studied in 18 patients with PD, 18 patients with PDD, and 13 normal controls that were matched for age, disease duration, and severity of symptoms. The heart to mediastinum ratio (H/M ratio) was calculated. The mean value of H/M ratio of PDD and PD was significantly lower than normal controls. However, there were no differences between PDD and PD groups. Although cardiac I-123 MIBG scintigraphy did not distinguish PDD from PD, we wish to focus attention on sustained studies that are needed to differentiate other Lewy body disease from many dementia patients with PD features. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 241-244, 2012 [ABSTRACT FROM AUTHOR]

Abstract: Stroke is a leading cause of death and disability worldwide. Although neuroimaging has been used to examine brain changes related to recovery from stroke, cerebral perfusion changes after rehabilitation have yet to be elucidated. The aim of this study was to evaluate the regional cerebral blood flow (rCBF) changes and their associations with gross motor functions after neurorehabilitation therapy in stroke patients. A total of 7 patients with middle cerebral artery (MCA) infarction received conventional neurorehabilitation therapy twice per day for 4‐6 weeks on admission. Brain perfusion images were acquired before and after the therapy using acetazolamide‐challenged single photon emission computed tomography. A whole‐brain voxel‐wise analysis found increased rCBF in the contralesional prefrontal, precentral, and postcentral cortical areas and decreased rCBF in the ipsilesional insula, posterior orbital gyrus, and central operculum. Moreover, a region of interest analysis revealed that rCBF of the ipsilesional basal ganglia was positively correlated with motor function at baseline and follow‐up, and perfusion changes in the ipsilesional basal ganglia was positively correlated with changes in motor function. These findings suggest that the contralesional prefrontal and sensorimotor cortex may play compensatory roles during the motor recovery and that perfusion in the ipsilesional basal ganglia is closely associated not only with current functional status but also with clinical improvement after neurorehabilitation therapy in patients with MCA infarction. Further studies with larger sample size are warranted to investigate whether assessment of cerebral perfusion may be clinically useful in rehabilitation of stroke patients. [ABSTRACT FROM AUTHOR]

ABSTRACT This functional magnetic resonance imaging (fMRI) study investigated the secondary somatosensory area (SII) in humans, especially regarding the presence of distinctive spatial arrangements of neural subunits responding to different types of tactile stimuli. Ten healthy volunteers received four different sensory stimuli on the palmar side of the right hand-vibrotactile, pressure, warmth, and coolness. Based on group-level analysis of the fMRI data, all four of the somatosensory stimuli resulted in activations in the bilateral SII and insula as well as the SI contralateral to the stimulation. The spatial distribution of neural activations corresponding to each stimulus, as examined by cortical inflation technique, revealed significant overlaps, but also showed the differences in terms of its overall topology. The local maxima of the activation within the SII, corresponding to these stimuli, manifested distinctive spatial location. These results suggest that differential networks of the SII subregions are involved in the processing of the different nature of the tactile stimuli, while sharing common regions in the parietal operculum. [ABSTRACT FROM AUTHOR]

ABSTRACT Kyung-ok-ko (KOK) has been used for the treatment of central nervous system disorders such as amnesia, dementia, and cerebral ischemia. However, the effects of KOK on transient ischemic-induced neuronal damage are still unclear. We examined whether KOK improves functional recovery and has a neuroprotective effect on infarction volume after transient middle cerebral artery occlusion (MCAO). KOK (50, 100, and 200 mg/kg) was administered orally following reperfusion and twice per day for 14 days post-MCAO. Infarction volume was measured using 2% 2-3-5 triphenylterazolium (TTC) staining at 14 days post-MCAO and alteration in regional cerebral blood flow (rCBF) after KOK treatment was monitored. Functional improvement was evaluated using adhesive removal and treadmill tests at 1, 7, and 14 days post-MCAO. Also, apoptotic cell death was assessed by terminal deoxynucleotidyl-transferase mediated d-UTP-biotin nick end (TUNEL) in the peri-infarction region. The protein level of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), and interleukin-1β (IL-1β) was measured in the ischemic core, ischemic border zone, and contralateral hemisphere regions. The KOK-treated group showed both reduced infarction volume and behavior tests demonstrated a significant improvement as compared to the control. Also, in the KOK-treated group, rCBF was recovered to near normal levels. The apoptotic cells were significantly decreased as compared with the control group in the ischemic peri-infarction area. Furthermore, the level of TNF-α, IL-1β, and IL-1α was decreased. These results suggest that KOK may improve functional outcome by inhibiting inflammatory cytokines (TNF-α, IL-1β, and IL-1α) in neuronal injury such as ischemic stroke. [ABSTRACT FROM AUTHOR]

ABSTRACT Memantine's efficacy has been demonstrated in patients with moderate to severe Alzheimer's disease. However, memantine therapy is not typically used in treating Parkinson's disease dementia (PDD), although the deviating glutamatergic pattern evidenced in neuropathological findings suggests that N-methyl D-aspartate receptor antagonists in patients with Lewy-body disorder may be effective. Therefore, we conducted this longitudinal study to confirm the efficacy of memantine for PDD by analyzing comparative changes in regional cerebral blood flow (rCBF) and neuropsychological tests before and after memantine administration in PDD. A total of 18 patients with PDD were enrolled in this study. All patients underwent technetium-99m hexamethylpropyleneamine oxime single photon emission computed tomography and completed neuropsychological tests before and 12 months after memantine administration. This study showed that there was no significant difference in cognitive functioning before and after memantine administration. No significant difference in rCBF was observed in any regions at baseline compared to 12 months after memantine administration. Our results suggest that memantine delays the speed of deterioration in cognitive functioning and behavioral symptoms in PDD because we found no significant changes in rCBF and cognition after memantine treatment. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is associated with reduction of regional cerebral blood flow (rCBF) in various brain regions. Although nicergoline has been used to treat cognitive impairment in various types of dementia, the effect of nicergoline on brain perfusion in AD has not been elucidated. The aim of the study was to examine the effect of nicergoline on rCBF in patients with early AD using technetium‐99m hexamethylpropylene amine oxime single‐photon emission computed tomography (SPECT). For 1.7 years on average, 22 patients with early AD received nicergoline (30 mg twice daily) and acetylcholinesterase inhibitors (AChEI), whereas other 22 patients received AChEI only. All patients underwent assessment of dementia severity and SPECT scans at baseline and follow‐up. We compared baseline rCBF and annual percent change of rCBF between the two groups. There were no significant differences in rCBF between the groups at baseline. Although changes in dementia severity was not statistically different, the annual percent changes of rCBF were higher in the left temporal pole (−0.12 ± 3.95 vs −3.38 ± 3.30, P = 0.002) and middle cingulate gyrus (1.91 ± 3.58 vs −1.34 ± 3.17, P = 0.002) among the nicergoline group. Our study demonstrated that nicergoline treatment combined with AChEI either better preserves or further improves cerebral perfusion in the temporal and cingulate cortices in patients with early AD compared to AChEI treatment alone. These results may indicate potential beneficial effects of nicergoline on brain functions in AD. [ABSTRACT FROM AUTHOR]

Although N-methyl- d-aspartate (NMDA) receptor antagonists may have beneficial influences on cognition in patients with alcohol-related dementia (ARD), their effects on regional cerebral blood flow (rCBF) remain unknown. This study evaluated changes in rCBF in ARD patients after administration of NMDA receptor antagonist for 12 weeks using technetium-99m ethyl cysteinate dimer (Tc-99m ECD) single-photon emission computed tomography (SPECT). Twenty-eight ARD patients were administered memantine for 12 weeks and underwent clinical evaluations and brain SPECT scans at baseline and follow-up. Whole-brain changes in perfusion were examined on a voxel-by-voxel basis. At follow-up, the patients showed reduced rCBF in the left medial frontal gyrus, left cingulate gyrus, left claustrum, right brainstem, left superior temporal gyrus, bilateral fusiform gyrus, and left cerebellum. On the other hand, increased rCBF was found in the bilateral uncus, left parahippocampal gyrus, bilateral superior frontal gyrus, right inferior parietal lobule, left cuneus, and left superior temporal gyrus. Perfusion increases in various brain areas including the superior frontal, parahippocampal, and inferior parietal areas, which may play important roles in the pathophysiology of ARD, suggest potential benefits of NMDA receptor antagonists on brain functions in patients with ARD. [ABSTRACT FROM AUTHOR]

ABSTRACT Hyperhomocysteinemia is associated with the severity of human neurodegenerative diseases due to its neuronal and endothelial toxicities, and pretreatment of a catecho-O-methyltransferase (COMTI) could block the l-dopa induced elevation of serum Hcy levels in preclinical study. However, it is unclear whether hyperhomocysteinemia in the patients with Parkinson's disease (PD) is related to clinical progression or not. Therefore, we conducted this 2-year follow-up study to evaluate whether or not COMTI has an impact on the progression or severity of PD. Data for 50 PD patients (22 PD patients treated with l-Dopa and COMTI and 28 PD patients treated with l-Dopa alone) who were recruited for this study were compared with those of 19 healthy controls. All subjects underwent Tc-99m HMPAO SPECT and neurological evaluation including cognitive function. Serum homocysteine (Hcy) was measured at baseline and at the 2-year follow up visit. The result showed serum Hcy levels were greater in the two PD groups than the healthy control group ( P = 0.003), suggesting L-dopa induced hyperhomocysteinemia. However, the comparison between these two PD groups showed no significant differences in serum Hcy level as well as regional cerebral perfusion, cognitive function or motor severity at baseline and at 2 years, indicating that COMTI neither prevented l-dopa induced hyperhomocysteinemia nor delayed clinical progression. Given limitation of excluding advanced PD with late motor complications, future large-scale long-term followup studies are needed to clarify the effects of COMTI. [ABSTRACT FROM AUTHOR]

ABSTRACT Ultrasound application to neural tissues modifies their activity, and it is increasingly considered as a new mode of functional neuromodulation in both central and peripheral nervous system. We investigate that ultrasound focused to skin surface can induce differential peripheral sensations by modulating the activity of sensory receptors. Pulsed focused ultrasound was applied to the last digit of human hands for 10 s using combinations of acoustic frequencies (350 and 650 kHz), tone-burst-durations (0.1 and 1.0 ms), pulse repetition frequencies (10 and 100 Hz) with 1% duty cycle, and acoustic intensities (3-100 mW/cm2), divided into two ambient temperatures (20 and 40°C). On insonification, volunteers reported cooling, warming, vibrotactile sensations, and mild nociception, while there was no actual increase to the skin temperature. Continuous insonification, in contrast to pulsed insonification, failed to elicit these sensations. Our results suggest that pulsed ultrasound temporarily modifies the activity of the sensory receptors on the skin, and casts future utility in dermatological applications as well as in the field of haptic device interfaces. © 2014 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 24, 167-174, 2014 [ABSTRACT FROM AUTHOR]

The testis shows physiologic uptake in flourine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET). The purpose of this study was to examine the degree of FDG uptake of normal testis on PET/computed tomography (CT), especially in relationship to various clinical parameters. We obtained the maximum standardized uptake value (SUVmax) and the mean standardized uptake value (SUVmean) of each testis from PET/CT of 166 healthy men. We also calculated the testis-to-muscle (T/M) ratio, defined as the SUVmean of the testis divided by the SUVmean of the right thigh muscle. Subjects completed a questionnaire on their medical history and sexual habits, including frequency of sexual intercourse, latest date of sexual intercourse, and vasectomy history. We then evaluated the association between imaging parameters and sexual habits. The mean age of subjects was 48 ± 10 years (range, 21-74), and the mean volume of each testis was 17.1 ± 4.5 cm3 (range, 7.4-32.4). The mean SUVmax was 3.6 ± 0.5 (range, 2.2-5.5), the mean SUVmean was 2.5 ± 0.4 (range, 1.6-3.8), and the mean T/M ratio was 4.2 ± 0.8 (range, 2.3-7.3). Of the 166 subjects, 51 reported having sexual intercourse zero times per month and 109 had sexual intercourse at least per month. The interval between the latest date of sexual intercourse and PET/CT was less than 3 days in 48 subjects; between 3 days and 1 month in 58; and greater than 1 month in 60. Twenty subjects were currently vasectomized. The T/M ratio was significantly correlated with age ( P = 0.040) but not with sexual habits. On the PET/CT, normal testicular FDG uptake decreased as age increased. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 245-249, 2012 [ABSTRACT FROM AUTHOR]