Differences in resting state regional cerebral blood flow assessed with 99mTc-HMPAO SPECT and brain atlas matching between depressed patients with and without tinnitus

An increased occurrence of major depressive disorder has been reported in tinnitus patients, and of tinnitus in depressive patients. Involvement of several Brodmann areas (BAs) has been reported in tinnitus perception. The aim of this study was to assess the regional cerebral blood flow (rCBF) changes in depressed patients with and without tinnitus. The rCBF distribution at rest was compared among 45 patients with a lifetime prevalence of major depressive disorder, of whom 27 had severe tinnitus, and 26 normal healthy subjects. 99mTc-hexamethylenepropylene amine oxime (99mTc-HMPAO) single photon emission computed tomography (SPECT), using a three-headed gamma camera, was performed and the uptake in 34 functional sub-volumes of the brain bilaterally was assessed by a computerized brain atlas. Decreased rCBF in right frontal lobe BA 45 (P<0.05), the left parietal lobe BA 39 (P<0.00) and the left visual association cortex BA 18 (P<0.05) was found in tinnitus patients compared with non-tinnitus patients. The proportion of tinnitus patients with pronounced rCBF alterations in one or more of the temporal lobe BAs 41+21+22 was increased compared to gender matched controls (P<0.00) and patients without tinnitus (P<0.05). Positive correlations were found between trait anxiety scales from the Karolinska Scales of Personality and rCBF in tinnitus patients only in three limbic BAs (P<0.01), and inverse correlations in non-tinnitus patients only in five BAs subserving auditory perception and processing (P<0.05). rCBF differences between healthy controls and depressed patients with and without tinnitus were found in this study. The rCBF alterations were distributed in the cortex and were particularly specific in the auditory cortex. These findings suggest that taking audiological symptoms into account may yield more consistent results between rCBF studies of depression.     

A comparative technetium 99m hexamethylpropylene amine oxime SPET study in different types of dementia

Regional cerebral perfusion was evaluated by single photon emission computed tomography (SPET) using technetium 99m hexamethylpropylene amine oxime (^99mTc-HMPAO) as a tracer, in 13 control subjects and 44 age-matched patients suffering from dementia of the Alzheimer's type (DAT, n=19), presumed Pick's disease (n=5), idiopathic Parkinson's disease with dementia (DPD, n=15) and progressive supranuclear palsy (PSP, n=5). HMPAO uptake was measured in the superior frontal, inferior frontal, parietal, temporal and occipital cortices, and the perfusion values were expressed as cortical/cerebellar activity ratios. As compared with controls, tracer uptake ratios in the DAT group were significantly reduced over all cortical regions, with the largest defects in the parieto-temporal and superior frontal cortices. A marked hypoperfusion affecting the superior and inferior frontal cortices was found in Pick's disease, whereas a mild but significant hypoperfusion was observed only in the superior frontal cortex of patients with PSP. In the DPD group, HMPAO uptake was significantly reduced in the parietal, temporal and occipital cortices, but not in the frontal cortex. These results show that DAT and DPD share an opposite anteroposterior HMPAO uptake defect as compared with the Pick's and PSP groups. Offprint reprints to: M.O. Habert     

A comparative technetium 99m hexamethylpropylene amine oxime SPET study in different types of dementia

Regional cerebral perfusion was evaluated by single photon emission computed tomography (SPET) using technetium 99m hexamethylpropylene amine oxime (99mTc-HMPAO) as a tracer, in 13 control subjects and 44 age-matched patients suffering from dementia of the Alzheimer's type (DAT, n = 19), presumed Pick's disease (n = 5), idiopathic Parkinson's disease with dementia (DPD, n = 15) and progressive supranuclear palsy (PSP, n = 5). HMPAO uptake was measured in the superior frontal, inferior frontal, parietal, temporal and occipital cortices, and the perfusion values were expressed as cortical/cerebellar activity ratios. As compared with controls, tracer uptake ratios in the DAT group were significantly reduced over all cortical regions, with the largest defects in the parieto-temporal and superior frontal cortices. A marked hypoperfusion affecting the superior and inferior frontal cortices was found in Pick's disease, whereas a mild but significant hypoperfusion was observed only in the superior frontal cortex of patients with PSP. In the DPD group, HMPAO uptake was significantly reduced in the parietal, temporal and occipital cortices, but not in the frontal cortex. These results show that DAT and DPD share an opposite anteroposterior HMPAO uptake defect as compared with the Pick's and PSP groups.     

Posterior parietooccipital hypometabolism may differentiate mild cognitive impairment from dementia in Parkinson’s disease

Purpose

Patients with Parkinson’s disease (PD) may have normal cognition, mild cognitive impairment (MCI) or dementia. We investigated differences in cerebral metabolism associated with these three cognitive states and the relationship between metabolism and cognitive dysfunction.

Methods

FDG PET and a battery of neuropsychological tests were used to study PD patients with dementia (n?=?19), MCI (n?=?28) and normal cognition (n?=?21), and control subjects (n?=?20). Regional glucose metabolism in patients and controls was analysed using statistical parametric mapping (SPM8) corrected for age, motor severity and depression. Correlations between the mini-mental state examination score and Z-score values of the different cognitive domains with respect to cerebral FDG uptake were assessed using SPM8.

Results

PD patients with MCI (PD-MCI patients) exhibited decreased FDG uptake in the frontal lobe, and to a lesser extent in parietal areas compared with cognitively normal patients. Patients with dementia showed reduced metabolism in the parietal, occipital and temporal areas and a less extensive reduction in the frontal lobe compared with PD-MCI patients, while widespread hypometabolism was seen in comparison with patients with normal cognition. PD-MCI patients exhibited reduced FDG uptake in the parietal and occipital lobes and in localized areas of the frontal and temporal lobes compared with controls, whereas patients with dementia showed a widespread reduction of cortical metabolism. Mini-mental state examination score correlated positively with metabolism in several lobes, executive function with metabolism in the parietooccipitotemporal junction and frontal lobe, memory with temporoparietal metabolism, visuospatial function with occipitoparietal and temporal metabolism, and language with frontal metabolism.

Conclusion

PD patients with MCI exhibited hypometabolism in several cortical regions compared with controls, and in the frontal and parietal regions compared with cognitively normal patients. Hypometabolism was higher in patients with dementia than in those with MCI, mainly in the posterior cortical areas where it was correlated with visuospatial, memory and executive functions.     

A simple method for the detection of abnormal brain regions in Alzheimer’s disease patients using [11C]MP4A: Comparison with [123I]IMP SPECT

We have developed a radiolabeled lipophilic acetylcholine analogue, N-[11C]methylpiperidin-4-yl acetate ([11C]MP4A) to measure brain acetylcholinesterase (AChE) activity by positron emission tomography (PET) in vivo. Aiming to develop a new SPECT tracer similar to MP4A, we first proposed a simple method for diagnosing Alzheimer's disease (AD) using [11C]MP4A PET. We performed [11C]MP4A PET and N-isopropyl [123I]iodoamphetamine ([123I]IMP) SPECT in 13 patients with AD and in 17 normal controls (NC). We calculated the ratio of radioactivity of the cortical region of interest (ROI) to that of the cerebellum measured with [11C]MP4A PET (MP4A ratio) and the ratio of regional cerebral blood flow (rCBF) to that of the cerebellum measured with [123I]IMP SPECT (IMP ratio). Eleven cortical ROIs were placed in the frontal, sensorimotor, temporal, parietal, and occipital cortices in both hemispheres and in the posterior cingulate cortex, and z-score was calculated in each ROI in patients with AD compared with NC. When the z-score was 2 or more in a ROI, it was defined as a positive ROI. When a patient had 3 or more positive ROIs, the patient was diagnosed as having AD. The reduction in the MP4A ratio was greater than that in the IMP ratio in all cortical ROIs except for in the right parietal cortex and cingulate cortex in patients with AD. MP4A ratio method showed 92% sensitivity and the IMP ratio method 69% sensitivity for the diagnosis of AD. These results encourage us to develop a new SPECT tracer similar to MP4A for the diagnosis of AD.     

Changed cortical activity after anterior cruciate ligament reconstruction in a joint position paradigm: an EEG study

After reconstruction of the anterior cruciate ligament (ACL) afferent proprioceptive information from the knee joint may be altered. In order to examine changes in central activation patterns, spectral features of the electroencephalography (EEG) were measured. Patients after ACL reconstruction and healthy controls carried out an knee-angle reproduction task in a groups × limbs × trials design. Cortical activity was recorded using international standards. FFT were conducted to determine power at Theta, Alpha-1, Alpha-2 and Beta-1. Statistics show significantly larger aberrations in the reconstructed limbs compared with the controls whereas there are no differences between the uninvolved land controls. Brain activity demonstrates significantly higher frontal Theta-power (F3, F4, F8) in both limbs of the ACL group vs the controls and a significantly higher Alpha-2 power was shown in the ACL-reconstructed limb compared with controls at parietal positions (P3, P4). No such differences were found between the uninvolved side and the controls. The EEG was able to measure a change in joint position sense at the cortical level after the reconstruction of the ACL. The results of these findings might indicate differences in focused attention with involvement of the anterior cingulate cortex (frontal Theta) and sensory processing in the parietal somatosensory cortex (Alpha-2).     

Generalized multiple-layer appearance of the cerebral cortex with 3D FLAIR 7.0-T MR imaging

To examine the multiple-layer appearance of the cerebral cortex with fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging at 7.0 T, whole-brain volumetric three-dimensional (3D) magnetization prepared FLAIR images were acquired in 12 volunteers (0.8 3 0.8 3 0.8-mm spatial resolution). Signal intensity profiles were evaluated for the anterior frontal (Brodmann area [BA] 10), posterior frontal (BA 6), parietal (BA 7), precentral (BA 4), postcentral (BA 3), occipital (BA 18), and calcarine (BA 17) regions. Variance of the normalized profile was used as the metric for the multiple-layer appearance. Wilcoxon signed-rank tests were performed to compare variances of the profiles between all areas. All cortical areas showed multiple-layered appearances, with a prominent hyperintense band at the external surface of the cortex, a hypointense band deeper in the cortex, and a hyperintense third band. The ranking from least- to most-pronounced layer appearance was as follows: postcentral (variance, 0.04), posterior frontal (variance, 0.05), calcarine (variance, 0.05), precentral (variance, 0.06), parietal (variance, 0.08), anterior frontal (variance, 0.10), and occipital (variance, 0.11). Each region was significantly different from at least one other region. In conclusion, a multiple-layer appearance of the cerebral cortex was found for all cortical regions with high-spatial-resolution 3D FLAIR MR imaging at 7.0 T.     

Voxel-based comparison of rCBF SPET images in frontotemporal dementia and Alzheimer's disease highlights the involvement of different cortical networks

Characteristic patterns of regional cerebral blood flow (rCBF) reduction, as detected by technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO) single-photon emission tomography (SPET), may help clinicians in differentiating patients with frontotemporal dementia (FTD) from those with Alzheimer's disease (AD). However, in some cases these patients may share common rCBF abnormalities and the visual analysis and/or the region of interest (ROI) approach may not sensitively detect more localised focal changes that could be more specific for each pathology. Recently, automated voxel-by-voxel statistical analysis of perfusion brain maps has been applied to SPET images. This method has the advantage of including the rCBF information for the whole brain for statistical analysis without any a priori hypothesis regarding the regions possibly involved. This could result in a better characterisation of rCBF differences in brain regions while also reducing the operator's subjectivity and the time required for data analysis. The purpose of this study was to apply such a technique to highlight the specific brain areas showing a relative functional involvement in FTD and AD. Thus, we compared the relative rCBF patterns obtained in eight FTD patients with those obtained in 21 AD patients using (99m)Tc-HMPAO SPET and statistical parametric mapping (SPM). When FTD patients were compared with AD patients, relatively lower rCBF was observed in right medial frontal cortex (BA 8, 9, 10), right anterior cingulate cortex (BA 32), right temporal cortex (BA 21/22), right orbitofrontal cortex (BA 11) and ventrolateral prefrontal cortex (BA 47); in BA 47 the reduction was evident bilaterally but was more marked on the right side. On the other hand, when AD patients were compared with FTD patients, a significant relative rCBF decrease was found in the bilateral superior parietal cortex (BA 7); this decrease was more extensive on the left side, where it also included the inferior parietal (BA 40), superior occipital (BA 19) and temporo-occipital regions (BA 39, 19). The results of this study confirm the preferential involvement of the frontotemporal regions in FTD patients and of the temporoparietal regions in AD patients. Furthermore, they highlight the networks that are more specifically impaired in these disorders and that could be implicated in the emotional-behavioural and cognitive disturbances that characterise FTD and AD respectively.     

Increased brain amyloid deposition in patients with a lifetime history of major depression: evidenced on 18F-florbetapir (AV-45/Amyvid) positron emission tomography

Purpose

The literature suggests that a history of depression is associated with an increased risk of developing Alzheimer’s disease (AD). The aim of this study was to examine brain amyloid accumulation in patients with lifetime major depression using ¹⁸F-florbetapir (AV-45/Amyvid) PET imaging in comparison with that in nondepressed subjects.

Methods

The study groups comprised 25 depressed patients and 11 comparison subjects who did not meet the diagnostic criteria for AD or amnestic mild cognitive impairment. Vascular risk factors, homocysteine and apolipoprotein E (ApoE) genotype were also examined. The standard uptake value ratio (SUVR) of each volume of interest was analysed using whole the cerebellum as the reference region.

Results

Patients with a lifetime history of major depression had higher ¹⁸F-florbetapir SUVRs in the precuneus (1.06?±?0.08 vs. 1.00?±?0.06, p?=?0.045) and parietal region (1.05?±?0.08 vs. 0.98?±?0.07, p?=?0.038) than the comparison subjects. Voxel-wise analysis revealed a significantly increased SUVR in depressed patients in the frontal, parietal, temporal and occipital areas (p?<?0.01). There were no significant associations between global ¹⁸F-florbetapir SUVRs and prior depression episodes, age at onset of depression, or time since onset of first depression.

Conclusion

Increased ¹⁸F-florbetapir binding values were found in patients with late-life major depression relative to comparison subjects in specific brain regions, despite no differences in age, sex, education, Mini Mental Status Examination score, vascular risk factor score, homocysteine and ApoE ε4 genotype between the two groups. A longitudinal follow-up study with a large sample size would be worthwhile.     

脑功能磁共振对梗死后抑郁症的研究

目的 采用功能性磁共振方法对梗死后抑郁症(PSD)患者观察正性、中性、负性情绪图片后的脑功能成像差异.资料与方法 对11例PSD患者和15名健康志愿者(NORM)进行正性、中性、负性情绪图片刺激下的脑功能磁共振成像研究.结果 PSD组及NORM组观察情绪图片时均主要激活额叶皮层-皮层下网状系统、基底节区(丘脑、苍白球、尾状核)和边缘系统(海马、海马旁回、杏仁核)、岛叶、颞叶,脑干及小脑.两组间有显著组间差异的激活脑区主要有海马旁回、海马、额中回、顶上小叶,扣带回(中性),右侧背侧丘脑、岛叶(正性),右侧杏仁核(负性).结论 PSD与边缘系统(海马、海马旁回、杏仁核)以及额中回、顶上小叶、扣带回、背侧丘脑、岛叶等有密切关系,上述脑区的损害可能参与了PSD的病理生理机制.     

Brain MRI and SPECT in the diagnosis of early neurological involvement in Wilson’s disease

Purpose To evaluate the impact of brain MRI and single-photon emission computed tomography (SPECT) in early detection of central nervous system abnormalities in patients affected by Wilson’s disease (WD) with or without neurological involvement. Methods Out of 25 consecutive WD patients, 13 showed hepatic involvement, ten hepatic and neurological manifestations, and twp hepatic, neurological, and psychiatric symptoms, including mainly movement disorders, major depression, and psychosis. Twenty-four healthy, age–gender matched subjects served as controls. All patients underwent brain MRI and ^99mTc-ethyl-cysteinate dimer (ECD) SPECT before starting specific therapy. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare differences in ^99mTc-ECD brain uptake between the two groups. Results Brain MRI showed T2-weighted hyperintensities in seven patients (28%), six of whom were affected by hepatic and neurological forms. Brain perfusion SPECT showed pathological data in 19 patients (76%), revealing diffuse or focal hypoperfusion in superior frontal (Brodmann area (BA) 6), prefrontal (BA 9), parietal (BA 40), and occipital (BA 18, BA 39) cortices in temporal gyri (BA 37, BA 21) and in caudatus and putamen. Moreover, hepatic involvement was detected in nine subjects; eight presented both hepatic and neurological signs, while two exhibited WD-correlated hepatic, neurological, and psychiatric alterations. All but one patient with abnormal MRI matched with abnormal ECD SPECT. Pathologic MRI findings were obtained in six out of ten patients with hepatic and neurological involvement while abnormal ECD SPECT was revealed in eight patients. Both patients with hepatic, neurological, and psychiatric involvement displayed abnormal ECD SPECT and one displayed an altered MRI. Discussion These findings suggest that ECD SPECT might be useful in detecting early brain damage in WD, not only in the perspective of assessing and treating motor impairment but also in evaluating better the less investigated disorders in the cognitive domain.     

SPECT imaging for brain improvement quantification in a patient with cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis is a rare recessive autosomal disease caused by mutations of the sterol 27-hydroxylase gene (CYP27), which leads to reduced synthesis of bile acids, particularly chenodeoxycholic acid (Cali et al, J Biol Chem. 1991;266:7779-7783; Gallus et al, Neurol Sci. 2006;27:143-149). The disease is characterized by progressive neurologic dysfunction due to accumulation of cholestanol in neurologic tissues (Moghadasian et al, Arch Neurol. 2002;59:527-529; Selva-O'Callaghan et al, Rheumatology. 2007;46:1212-1213). Long-term treatment with chenodeoxycholic acid can arrest or even reverse progression of the disease (Pierre et al, J Inherit Metab Dis. In press).Brain SPECT with 740 MBq of Tc-99m ethyl cysteinate dimmer, using a double-head gamma camera (Siemens E.cam) with high-resolution, low-energy parallel collimators was performed in our patient at onset and 2 years after starting chenodeoxycholic acid treatment. SPECT acquisitions were performed using a 360-degree orbit, 1 image/30 seg/3 degree, and 128 × 128 matrix. Reconstruction was by means of filtered back-projection, Butterworth 5/0.25, without attenuation correction. Pre- and post-SPECT dicom images were reoriented into Talairach space using NeuroGam (Segami Corporation). To visually identify abnormal perfusion regions, volume render brain image was computed, where abnormal perfusion regions were found by comparing with age-matched normal database, and Brodmann areas (BA) were quantified. Pre- versus post-treatment changes were computed by means of relative percentage between counts. Post-treatment SPECT showed better perfusion than pretreatment SPECT with an increase between 5% and 10% in frontal cortex (BA 9, BA 24, BA 32, BA 46, BA 47), parietal cortex (BA 5, BA 31), and temporal cortex (BA 20, BA 22, BA 28, BA 36, BA 37, BA 38), and with an increase of more than 10% in frontal cortex (BA 45) and parietal cortex (BA 23). This case illustrates the benefit of bile acid therapy for halting and even reversing neurologic retardation in this condition.     

Abnormal brain function in neuromyelitis optica: A fMRI investigation of mPASAT

PurposeCognitive impairment with the Neuromyelitis Optica (NMO) patients is debated. The present study is to study patterns of brain activation in NMO patients during a pair of task-related fMRI.Materials and methodsWe studied 20 patients with NMO and 20 control subjects matched for age, gender, education and handedness. All patients with NMO met the 2006 Wingerchuk diagnostic criteria. The fMRI paradigm included an auditory attention monitoring task and a modified version of the Paced Auditory Serial Addition Task (mPASAT). Both tasks were temporally and spatially balanced, with the exception of task difficulty.ResultsIn mPASAT, Activation regions in control subjects included bilateral superior temporal gyri (BA22), left inferior frontal gyrus (BA45), bilateral inferior parietal lobule (BA7), left cingulate gyrus (BA32), left insula (BA13), and cerebellum. Activation regions in NMO patients included bilateral superior temporal gyri (BA22), left inferior frontal gyrus (BA9), right cingulate gyrus (BA32), right inferior parietal gyrus (BA40), left insula (BA13) and cerebellum. Some dispersed cognition related regions are greater in the patients.ConclusionsThe present study showed altered cerebral activation during mPASAT in patients with NMO relative to healthy controls. These results are speculated to provide further evidence for brain plasticity in patients with NMO.     

99mTc-ECD brain perfusion SPET: variability, asymmetry and effects of age and gender in healthy adults

Reliable and high-resolution reference data for regional cerebral blood flow measured with single-photon emission tomography (SPET) are necessary for optimal clinical and research use. Therefore, a large dataset of normal technetium-99m labelled ethylene cysteine dimer (ECD) perfusion SPET in carefully screened healthy volunteers with an age range spanning six decades was created, with correction for non-uniform attenuation and scatter and based on an anatomically standardised analysis. Eighty-nine healthy volunteers, stratified for gender (46 females, 43 males; age 20-81 years), were included. Twelve volunteers underwent repeated 99mTc-ECD SPET after 2.5+/-2.3 weeks. An automated whole-brain volume of interest analysis with MANOVA as well as voxelwise analysis using SPM99 was conducted. Average intersubject variability was 4.8% while intrasubject reproducibility was 3.0%. An age-related decline in tracer uptake was found in the anterior cingulate gyrus, bilateral basal ganglia, left prefrontal, left lateral frontal and left superior temporal and insular cortex (all P=0.001-0.02). There was an overall increase in right/left asymmetry with age, which was most pronounced in the frontal and temporal neocortex. The most significant correlations between AI and age decade were found in the prefrontal (R=0.35, P=0.001) and superior temporal neocortex (R=0.43, P<0.001). Women had significantly higher uptake in the right parietal cortex (P<0.001), while men showed higher uptake in the cerebellum and the left anterior temporal and orbitofrontal cortex (all P<0.01). This normative dataset allows age- and gender-specific patient and group assessment of 99mTc-ECD perfusion SPET under a wide variety of clinical circumstances in relation to normal variations and highlights the importance of both age- and gender-specific normal datasets for optimal analysis sensitivity.     

A comparison of 99mTc-HMPAO SPET changes in dementia with Lewy bodies and Alzheimer's disease using statistical parametric mapping

Differences in regional cerebral blood flow (rCBF) between subjects with Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and healthy volunteers were investigated using statistical parametric mapping (SPM99). Forty-eight AD, 23 DLB and 20 age-matched control subjects participated. Technetium-99m hexamethylpropylene amine oxime (HMPAO) brain single-photon emission tomography (SPET) scans were acquired for each subject using a single-headed rotating gamma camera (IGE CamStar XR/T). The SPET images were spatially normalised and group comparison was performed by SPM99. In addition, covariate analysis was undertaken on the standardised images taking the Mini Mental State Examination (MMSE) scores as a variable. Applying a height threshold of P < or = 0.001 uncorrected, significant perfusion deficits in the parietal and frontal regions of the brain were observed in both AD and DLB groups compared with the control subjects. In addition, significant temporoparietal perfusion deficits were identified in the AD subjects, whereas the DLB patients had deficits in the occipital region. Comparison of dementia groups (height threshold of P < or = 0.01 uncorrected) yielded hypoperfusion in both the parietal [Brodmann area (BA) 7] and occipital (BA 17, 18) regions of the brain in DLB compared with AD. Abnormalities in these areas, which included visual cortex and several areas involved in higher visual processing and visuospatial function, may be important in understanding the visual hallucinations and visuospatial deficits which are characteristic of DLB. Covariate analysis indicated group differences between AD and DLB in terms of a positive correlation between cognitive test score and temporoparietal blood flow. In conclusion, we found evidence of frontal and parietal hypoperfusion in both AD and DLB, while temporal perfusion deficits were observed exclusively in AD and parieto-occipital deficits in DLB.     

应用局部一致性研究静息态脑功能磁共振成像的性别差异

目的:应用局部一致性的数据分析方法,将fMRI应用于正常人静息态的研究,从局部一致性的角度探讨静息态的性别差异。方法:将21例健康志愿者分为男性组、女性组,采集静息态下的fMRI数据,应用局部一致性方法个体激活图及组激活图;对数据行双样本t检验。结果:男性组较女性组差异有统计意义的激活区为右侧枕叶舌回(BA18)、左侧小脑、右侧枕叶(BA19)、右侧颞下回(BA20)、右侧颞上回(BA22)、左侧顶下小叶(BA22)、右侧楔前叶(BA7)、左侧后扣带回(BA31)、左侧额上回后外侧(BA9)、右侧额中回后部(BA6)、左侧缘上回(BA40)、右侧前扣带回(BA24);激活范围最大区域和激活强度最强均为右侧枕叶舌回(BA18)。女性组较男性组差异有统计意义的激活区为右侧颞下回(BA20)、左侧颞下回(BA20)、桥脑、左侧小脑、左侧颞极区(BA38)、右侧额极区(BA10)、左侧海马旁回(BA34)、左侧中央后回(BA3);激活范围最大区域为右侧额极区(BA10);激活强度最强为桥脑。结论:正常人静息态下的局部一致性存在性别差异。     

Diffusion tensor imaging in patients with acute onset of neuropsychiatric systemic lupus erythematosus: a prospective study of apparent diffusion coefficient, fractional anisotropy values, and eigenvalues in different regions of the brain

PURPOSE: To investigate whether apparent diffusion coefficient (ADC), fractional anisotropy (FA), and eigenvalues in neuropsychiatric systemic lupus erythematosus (NPSLE) patients differ from those of healthy controls. MATERIAL AND METHODS: Eight NPSLE patients (aged 23-55 years, mean 42.9 years) and 20 healthy age-matched controls (aged 22-59 years, mean 44.4 years) underwent conventional brain magnetic resonance (MR) and diffusion tensor imaging (DTI). The ADC, FA, principal eigenvalue (lambda parallel), and the corresponding average perpendicular eigenvalue (lambda perpendicular) (=(lambda2+lambda3)/2) were measured in selected regions of normal appearing gray and white matter brain parenchyma. For statistical evaluation of differences between the two groups, a Student's t-test was used. The P value for statistical significance was set to P=0.0025 after Bonferroni correction for multiple measurements. RESULTS: Significantly increased ADC values were demonstrated in normal-appearing areas in the insular cortex (P<0.001), thalamus (P<0.001), and the parietal and frontal white matter (P<0.001 and P<0.001, respectively) in NPSLE patients. Significantly decreased FA values were demonstrated in normal-appearing thalamus (P<0.001), corpus callosum (P=0.002), and in the parietal and frontal white matter (P<0.001 and P<0.001, respectively) in NPSLE patients compared to healthy controls. The lambda perpendicular was significantly higher in several of these regions in NPSLE patients compared to healthy controls. CONCLUSION: Our study demonstrates alterations in normal-appearing gray and white matter brain parenchyma of patients with NPSLE by means of abnormal ADC, FA, and eigenvalues. These alterations may be based on loss of tissue integrity in part due to demyelination. It is possible that DTI in the future could assist in the diagnosis of NPSLE and possibly help to further elucidate the pathogenesis of NPSLE.     

Riluzole protects Huntington disease patients from brain glucose hypometabolism and grey matter volume loss and increases production of neurotrophins

Purpose  Huntington disease (HD) mutation increases gain-of-toxic functions contributing to glutamate-mediated excitotoxicity. Riluzole interferes with glutamatergic neurotransmission, thereby reducing excitotoxicity, enhancing neurite formation in damaged motoneurons and increasing serum concentrations of BDNF, a brain cortex neurotrophin protecting striatal neurons from degeneration. Methods  We investigated metabolic and volumetric differences in distinct brain areas between 11 riluzole-treated and 12 placebo-treated patients by MRI and ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) PET scanning, according to fully automated protocols. We also investigated the influence of riluzole on peripheral growth factor blood levels. Results  Placebo-treated patients showed significantly greater proportional volume loss of grey matter and decrease in metabolic FDG uptake than patients treated with riluzole in all cortical areas (p<0.05). The decreased rate of metabolic FDG uptake correlated with worsening clinical scores in placebo-treated patients, compared to those who were treated with riluzole. The progressive decrease in metabolic FDG uptake observed in the frontal, parietal and occipital cortex correlated linearly with the severity of motor scores calculated by Unified Huntington Disease Rating Scale (UHDRS-I) in placebo-treated patients. Similarly, the rate of metabolic changes in the frontal and temporal areas of the brain cortex correlated linearly with worsening behavioural scores calculated by UHDRS-III in the placebo-treated patients. Finally, BDNF and transforming growth factor beta-1 serum levels were significantly higher in patients treated with riluzole. Conclusion  The linear correlation between decreased metabolic FDG uptake and worsening clinical scores in the placebo-treated patients suggests that FDG-PET may be a valuable procedure to assess brain markers of HD.     

Evaluation of dysthymic disorder with technetium-99 m hexamethylpropylene amine oxime brain single-photon emission tomography

Dysthymic disorder is a chronic disorder characterised by the presence of a depressed mood and is classified as a distinct category in DSM-IV, separately from major depression. Although brain imaging studies have been performed in major depressive disease, there have to date been no reports of such studies in dysthymic disorder. In this study 36 patients with dysthymic disorder were compared with 16 normal subjects using technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography. A relative blood flow ratio was calculated for each region of interest using the average tissue activity in the region divided by activity in the cerebellum. There were significant differences in the bilateral inferior frontal, bilateral parietal, right superior frontal and left posterior temporal regions in the patients with dysthymic disorder compared with the healthy controls. These findings support the hypothesis that the biological bases for dysthymic disorder and major depression are similar. Recognition of these regional abnormalities may have clinical utility in both the diagnosis and the treatment of dysthymic disorder. Further studies are needed to confirm our results and to assess the influence of treatment in patients with dysthymic disorder. Received 14 August and in revised form 24 October 1998