99mTc-ECD Single Photon Emission Computed Tomography Research Articles

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

BackgroundBlood-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. MethodsBetween 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. ResultsThunderclap 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. ConclusionReduced 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.

Different hemodynamics of basal ganglia between moyamoya and non-moyamoya diseases using intravoxel incoherent motion imaging and single-photon emission computed tomography.

Moyamoya disease (MMD) and non-MMD have different pathogenesis, clinical presentation, and treatment policy. To identify differences in hemodynamics between MMD and non-MMD using intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT). Patients who had undergone 99mTc-ECD or 123I-IMP SPECT, and IVIM imaging were retrospectively studied. IVIM imaging was acquired using six different b-values. Cerebral blood flow ratio (CBFR) in the basal ganglia was calculated using a standardized volume-of-interest template. The cerebellum was used as a reference region. IVIM perfusion fraction (f) was obtained using a two-step fitting algorithm. Elliptical regions of interest were placed in bilateral basal ganglia on the IVIM f map. Patients were classified into MMD and non-MMD groups. The correlation between CBFR and mean IVIM f (fmean) in the basal ganglia was evaluated using Spearman's rank correlation coefficient. In total, 20 patients with MMD and 28 non-MMD patients were analyzed. No significant differences in fmean were observed among MMD, affected hemisphere with non-MMD (non-MMDaff), and unaffected hemispheres with non-MMD (non-MMDunaff). A negative correlation was seen between fmean and CBFR in the MMD group (r = -0.40, P = 0.0108), but not in the non-MMD group (non-MMDaff, r = 0.07, P = 0.69; non-MMDunaff, r = -0.22, P = 0.29). No significant differences were found among MMD and non-MMD patients, irrespective of SPECT tracers. The combination of IVIM MRI and SPECT appears to allow non-invasive identification of differences in hemodynamics between MMD and non-MMD.

Reduced cerebral blood flow of lingual gyrus associated with both cognitive impairment and gait disturbance in patients with idiopathic normal pressure hydrocephalus

BackgroundIdiopathic normal pressure hydrocephalus (iNPH) is primarily characterized by cognitive impairment and gait disturbance. Our objective was to evaluate the clinical characteristics of iNPH and the association between cerebral blood flow (CBF), measured using single-photon emission computed tomography (SPECT), and both cognitive and gait disturbances in iNPH patients. MethodsWe compared cognitive and motor functions and neuroimaging findings between 29 iNPH patients and 35 age-matched Parkinson's disease (PD) patients. We examined the associations between cognitive and motor dysfunctions and CBF in iNPH patients using 99mTc-ECD SPECT subtraction imaging data from a database of healthy control subjects. ResultsThe cognitive function of iNPH patients, as measured by the Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB), was significantly poorer than that of PD patients; however motor function of the legs based on the Unified PD Rating Scale (UPDRS) part III was similar across groups. Impairment in cognitive function based on the MMSE and FAB was significantly correlated with motor dysfunction of the legs on the UPDRS part III and the 3-m Timed Up and Go test. Furthermore, 99mTc-ECD SPECT subtraction imaging revealed lower CBF in the bilateral lingual gyrus of iNPH patients with severely impaired cognitive and motor functions than healthy control subjects. ConclusionPatients with iNPH have severely impaired cognitive function; however, motor dysfunction of the legs is similar to PD patients. The cognitive and gait disturbances of iNPH are significantly interrelated, which may be associated with an impaired brain network that includes the bilateral lingual gyrus.

Significance of combined use of MRI and perfusion SPECT for evaluation of multiple system atrophy, cerebellar type.

Multiple system atrophy, cerebellar type (MSA-C) sometimes shows asymmetrical findings on magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). To assess the frequency and clinical significance of asymmetrical MRI and (99m)Tc-ethyl cysteinate dimer perfusion (ECD) SPECT findings of the cerebellum, middle cerebellar peduncle (MCP), and pons in MSA-C patients. We retrospectively reviewed 28 patients with MSA-C who underwent MRI and (99m)Tc-ECD SPECT and evaluated laterality of atrophy and signal changes on MRI, and laterality of perfusion on (99m)Tc-ECD SPECT transversely and longitudinally. Laterality was identified for 64%, 61%, and 21% of atrophy in the cerebellum, MCP, and pons, respectively, on MRI and for 71% of atrophy in the cerebellum on perfusion SPECT. Concerning comparisons between the latest MRI and SPECT findings, laterality of cerebellar/MCP atrophy on MRI and decreased cerebellar perfusion on SPECT was matched in 57%, mismatched in 11%, and absent in 25% of patients. On past images, MRI and SPECT showed matched laterality in 33%, mismatched laterality in 27%, no laterality in 13%, and SPECT precedent laterality in 27% of patients. Including the latest and past images, asymmetrical changes were observed in 75% of patients. We could not identify any correlation between laterality of image findings and cerebellar symptoms in most patients. Asymmetrical changes on MRI and perfusion SPECT are common in MSA-C patients. Perfusion SPECT is useful for diagnosing MSA-C in the early stages from a functional perspective.

Sleep Deprivation Reveals Altered Brain Perfusion Patterns in Somnambulism.

BackgroundDespite its high prevalence, relatively little is known about the pathophysiology of somnambulism. Increasing evidence indicates that somnambulism is associated with functional abnormalities during wakefulness and that sleep deprivation constitutes an important drive that facilitates sleepwalking in predisposed patients. Here, we studied the neural mechanisms associated with somnambulism using Single Photon Emission Computed Tomography (SPECT) with 99mTc-Ethylene Cysteinate Dimer (ECD), during wakefulness and after sleep deprivation.MethodsTen adult sleepwalkers and twelve controls with normal sleep were scanned using 99mTc-ECD SPECT in morning wakefulness after a full night of sleep. Eight of the sleepwalkers and nine of the controls were also scanned during wakefulness after a night of total sleep deprivation. Between-group comparisons of regional cerebral blood flow (rCBF) were performed to characterize brain activity patterns during wakefulness in sleepwalkers.ResultsDuring wakefulness following a night of total sleep deprivation, rCBF was decreased bilaterally in the inferior temporal gyrus in sleepwalkers compared to controls.ConclusionsFunctional neural abnormalities can be observed during wakefulness in somnambulism, particularly after sleep deprivation and in the inferior temporal cortex. Sleep deprivation thus not only facilitates the occurrence of sleepwalking episodes, but also uncovers patterns of neural dysfunction that characterize sleepwalkers during wakefulness.

Old wine in new bottles: Validating the clinical utility of SPECT in predicting cognitive performance in mild traumatic brain injury

The neural underpinnings of cognitive dysfunction in mild traumatic brain injury (TBI) are not fully understood. Consequently, patient prognosis using existing clinical imaging is somewhat imprecise. Single photon emission computed tomography (SPECT) is a frequently employed investigation in this population, notwithstanding uncertainty over the clinical utility of the data obtained. In this study, subjects with mild TBI underwent 99mTc-ECD SPECT scanning, and were administered a brief battery of cognitive tests and self-report symptom scales of concussion and emotional distress. Testing took place 2 weeks (n=84) and 1 year (n=49) post-injury. Multivariate analysis (i.e., partial least squares analysis) revealed that frontal perfusion in right superior frontal and middle frontal gyri predicted poorer performance on the Stroop test, an index of executive function, both at initial and follow-up testing. Conversely, SPECT scans categorized as normal or abnormal by radiologists did not differentiate cognitively impaired from intact subjects. These results demonstrate the clinical utility of SPECT in mild TBI, but only when data are subjected to blood flow quantification analysis.

Concordance between 99mTc‐ECD SPECT and 18F‐FDG PET interpretations in patients with cognitive disorders diagnosed according to NIA‐AA criteria

The purpose of this study was to clarify the concordance of diagnostic abilities and interobserver agreement between 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and brain perfusion single photon-emission computed tomography (SPECT) in patients with Alzheimer's disease (AD) who were diagnosed according to the research criteria of the National Institute of Aging-Alzheimer's Association Workshop. Fifty-five patients with "AD and mild cognitive impairment (MCI)" (n = 40) and "non-AD" (n = 15) were evaluated with 18F-FDG PET and (99m)Tc-ethyl cysteinate dimer (ECD) SPECT during an 8-week period. Three radiologists independently graded the regional uptake in the frontal, temporal, parietal, and occipital lobes as well as the precuneus/posterior cingulate cortex in both images. Kappa values were used to determine the interobserver reliability regarding regional uptake. The regions with better interobserver reliability between 18F-FDG PET and (99m)Tc-ECD SPECT were the frontal, parietal, and temporal lobes. The (99m)Tc-ECD SPECT agreement in the occipital lobes was not significant. The frontal, temporal, and parietal lobes showed good correlations between 18F-FDG PET and (99m)Tc-ECD SPECT in the degree of uptake, but the occipital lobe and precuneus/posterior cingulate cortex did not show good correlations. The diagnostic accuracy rates of "AD and MCI" ranged from 60% to 70% in both of the techniques. The degree of uptake on 18F-FDG PET and (99m)Tc-ECD SPECT showed significant correlations in the frontal, temporal, and parietal lobes. The diagnostic abilities of 18F-FDG PET and (99m)Tc-ECD SPECT for "AD and MCI," when diagnosed according to the National Institute of Aging-Alzheimer's Association Workshop criteria, were nearly identical.

Brain perfusion SPECT in limbic encephalitis associated with autoantibody against the glutamate receptor epsilon 2

The aim of this study was to elucidate the single-photon emission computed tomography (SPECT) pattern at the acute stage of disease in non-herpetic limbic encephalitis (NHLE) patients associated with the N-methyl-D-aspartate-type glutamate receptor epsilon 2 (GluR ϵ2) autoantibody using Z-score imaging system (eZIS) analyses. Brain magnetic resonance imaging (MRI) and brain perfusion SPECT using technetium-99 ethyl cysteinate dimer ((99m)Tc-ECD) were performed in eight patients with NHLE (5 men and 3 women; mean age 48.8±22 years) within 20days after clinical onset. All patients had various clinical limbic-associated symptoms and no evidence of herpes simplex infection or systemic malignancies. Two of eight patients showed abnormally hyperintense lesions on diffusion-weighted images and significant hyperperfusion in ipsilateral cerebral cortex on eZIS analysis, whereas other patients showed normal MRI findings and significant hypoperfusion in one or both sides of the limbic and paralimbic areas. We suggest that (99m)Tc-ECD SPECT study using eZIS analyses may be helpful to detect the neuronal dysfunction, particularly in NHLE patients without abnormal MRI findings.

Evaluation of FDG-PET and ECD-SPECT in patients with subcortical band heterotopia

Objective: The purpose of this retrospective study was to clarify the cellular activities of ectopic neurons in subcortical bands and to evaluate the imaging features of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and 99mTc ethyl cysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in a series of patients with subcortical band heterotopia (SBH). Materials and methods: The cases of 12 patients with SBH (3 men and 9 women; age range, 2–51years) were evaluated on the basis of their MRI findings. Eight 18F-FDG PET and 12 99mTc-ECD SPECT images were obtained. The uptakes of these images were compared with electroencephalography (EEG) or MRI findings such as band thickness. In all patients, easy Z-score Imaging System (eZIS) software was used to statistically analyze the SPECT images. Results: Of the eight 18F-FDG PET images, five showed higher uptake in the thick subcortical bands than in the overlying cortex. Of the 12 99mTc-ECD SPECT examinations with eZIS images, nine indicated increased regional cerebral blood flow (rCBF) areas corresponding to the band locations. Of the eight 18F-FDG PET examination findings, six were congruent with the rCBF distributions on the eZIS images. Eight of the 12 patients showed correspondence to the increased rCBF on the eZIS images, the band locations on MRI, and abnormal discharge sites on EEG. Conclusions: Ectopic neurons in subcortical bands may have higher glucose metabolism and/or increased rCBF compared to the overlying cortex. 18F-FDG PET and 99mTc-ECD SPECT using eZIS can be helpful to clearly detect the cellular activities of ectopic neurons in patients with SBH.

The influence of the tracer injection–acquisition interval on the distribution of 99mTc-ECD in the brain of laboratory cats

Abstract Single-photon emission computed tomography (SPECT) can be used to study the regional distribution of the cerebral blood flow in the feline brain without interference of anesthetics. When the tracer, 99m technetium-ethyl cysteinate dimer ( 99m Tc-ECD), is injected in the awake animal, the acquisition can be performed afterward under general anesthesia, whereas the tracer distribution still represents the regional cerebral blood flow (rCBF) in the awake animal. The aim of this study was to look at the in vivo stability of 99m Tc-ECD in the feline brain. For this purpose, 6 cats (n = 6) were used, and 3 serial acquisitions were performed starting at 40 (T40), 60 (T60), and 85 (T85) minutes after tracer injection. Total counts and perfusion indices (PIs), normalized to the total brain and to the cerebellum, were calculated. When T85 was compared with T40, total counts decreased, depending on the brain region, with 29% (left thalamus) to 51% (bulbus olfactorius). These regional differences in tracer clearance resulted in significantly altered PIs at T85 as compared with T40. This study shows that 99m Tc-ECD SPECT can be used in cats for studying the rCBF and that the clearance of 99m Tc-ECD in the feline brain is region dependent. As a result, the acquisition should be started between 40 and 60 minutes after tracer injection.

99mTc-ECD SPECT at rest and activation in young patients with schizophrenia

Abstract The aim of the study was to localize brain parts involved in executive functions in patients with schizophrenia by means of 99mTc-ECD single photon emission computed tomography (SPECT) with 3-dimensional automatic software. We examined 12 men with schizophrenia (mean age 29±3.9 years). Brain perfusion SPECT was performed at rest and during Wisconsin Card Sorting Test (WCST). Two types of quantitative SPECT analysis were applied; voxel-based and volume of interest (VOI)-based. With voxel-based approach, rest and activation SPECT were compared. VOI-based analysis allowed for correlation of regional cerebral blood flow (rCBF) in 20 VOIs with WCST scores. In voxel-based analysis, the patterns of rCBF decrease and increase after activation varied between patients, with combinations of different brain regions involved. In VOI-based approach, the only statistically significant difference between activation and rest was rCBF decrease in the left basal ganglia (p=0.028). The thalami and right temporal cortex correlated with the greatest number of WCST scores, followed by left occipital cortex and left cerebellum. In conclusion, our results suggest that patterns of WCST activation and deactivation vary between patients with schizophrenia. Among the network of involved brain structures, right temporal cortex and thalami appear to play the major role.

Correlation of defects in regional cerebral blood flow determined by 99mTc SPECT with residual neurocognitive testing abnormalities during and 3 months post exposure in acutely poisoned patients with organophosphates

Introduction. Following acute organophosphate exposure, morphological changes in certain regions of the brain have been reported to develop within a few hours and involve neuronal degeneration. Single photon emission computed tomography (SPECT) has been used to determine changes in the regional cerebral blood flow and attempts have been made to correlate these changes with long-term neurological sequelae. Purpose of study. The aim of the study was to determine changes in the regional cerebral blood flow by 99mTc-ECD SPECT following acute organophosphate poisoning and to correlate these defects with abnormalities in neurocognitive testing carried out during admission and at 3 months post exposure, in order to determine whether any changes in the cerebral blood flow could help in predicting future development of neurocognitive deficit. Patients and methods. Twenty-eight patients with acute organophosphorous poisoning were included in the study. The inclusion criteria were a history of ingestion or accidental exposure, clinical features of cholinergic crises, and low serum acetylcholinesterase (AChE). Twenty age- and sex-matched patients from a previous study were used as controls for the neurocognitive tests. There were no controls for SPECT. Results. Of the 28 patients studied, 27 had abnormalities in the regional cerebral blood flow on SPECT with men having significantly higher abnormalities than women (p < 0.05). The right side of the brain had more defects than the left, with the occipital lobes being the most commonly involved. Of seven neurocognitive function tests carried out on patients who had regional cerebral blood flow defects during admission, abnormalities were observed in six tests. In 18 of 26 patients who could be tested at 3 months post exposure, improvement was observed in Trail B and Visual retention tests. However, others tests remained significantly abnormal. Conclusion. We conclude that a single episode of clinically significant organophosphate intoxication can lead to persistent residual neurocognitive deficits. Detection of regional cerebral blood flow defects on 99mTc-ECD SPECT can possibly help in predicting long-term deficits in neurocognitive functions in such patients.

Usefulness of 99mTc-ECD brain SPECT with voxel-based analysis in evaluation of perfusion changes early after carotid endarterectomy

SummaryBackgroundAssociation between preoperative perfusion pattern and reperfusion after carotid endarterectomy (CEA) is an important yet unexplored topic. Therefore, the aim of our study was to determine whether 99mTc-ECD single-photon emission computed tomography (SPECT) performed before carotid endarterectomy in patients with internal carotid artery (ICA) stenosis may be helpful in predicting early perfusion changes after revascularization.Material/MethodsThe examined group consisted of 30 patients (mean age 67.4±9.6 years) with ICA stenosis who underwent CEA. Infarction was demonstrated on computed tomography (CT) in 12 cases. Brain perfusion SPECT was performed 1–3 days before CEA and 3–5 days after the surgery. Voxel-based analysis was carried out with Brain SPECT Quantification software. For evaluation of preoperative interhemispheric asymmetry of perfusion, the percentage asymmetry index (AI) was calculated. For comparison of perfusion before and after CEA, the percentage relative difference (RD) was computed.ResultsBefore CEA, cerebral hypoperfusion was seen in 26 cases, including 15 participants with normal CT. After CEA, the following changes of perfusion were observed: perfusion increase n=18 (ipsilateral and bilateral), deterioration n=1, mixed patterns n=2, no change n=9. In patients with preoperative ipsilateral hypoperfusion and perfusion increase after CEA, AI correlated significantly with RD (r=0.48, p=0.04).ConclusionsOur results suggest that perfusion increase 3–5 days after CEA is higher in patients with greater ipsilateral asymmetry index. Evaluation of preoperative AI may help to identify patients in whom rapid reperfusion is more likely.

Optimized Data Preprocessing for Multivariate Analysis Applied to 99mTc-ECD SPECT Data Sets of Alzheimer's Patients and Asymptomatic Controls

Multivariate image analysis has shown potential for classification between Alzheimer's disease (AD) patients and healthy controls with a high-diagnostic performance. As image analysis of positron emission tomography (PET) and single photon emission computed tomography (SPECT) data critically depends on appropriate data preprocessing, the focus of this work is to investigate the impact of data preprocessing on the outcome of the analysis, and to identify an optimal data preprocessing method. In this work, technetium-99methylcysteinatedimer ((99m)Tc-ECD) SPECT data sets of 28 AD patients and 28 asymptomatic controls were used for the analysis. For a series of different data preprocessing methods, which includes methods for spatial normalization, smoothing, and intensity normalization, multivariate image analysis based on principal component analysis (PCA) and Fisher discriminant analysis (FDA) was applied. Bootstrap resampling was used to investigate the robustness of the analysis and the classification accuracy, depending on the data preprocessing method. Depending on the combination of preprocessing methods, significant differences regarding the classification accuracy were observed. For (99m)Tc-ECD SPECT data, the optimal data preprocessing method in terms of robustness and classification accuracy is based on affine registration, smoothing with a Gaussian of 12 mm full width half maximum, and intensity normalization based on the 25% brightest voxels within the whole-brain region.

Residual brain viability, evaluated by 99mTc-ECD SPECT, in patients with suspected brain death and with confounding clinical factors

In 1968, the Harvard criteria for brain death diagnosis were introduced in clinical practice. These include no movements or breathing, no reflexes, and flat electroencephalogram in the absence of confounding factors, including hypothermia, drugs, electrolyte, and endocrine disturbances. When confounding factors occur, confirmatory tests documenting the absence of cerebral blood flow, such as cerebral angiogram, transcranial Doppler sonography, computed tomography angiography, and nuclear techniques, are required. The aim of this study was to evaluate the clinical value of single-photon emission computed tomography (SPECT) with technetium-99m (Tc)-ECD in the diagnosis of brain death in a cohort of patients with confounding factors. Fifty-two patients were studied between 1 January 2000 and 23 September 2008. The criteria for the request for Tc-ECD SPECT were sodic thiopental withdrawal after less than 24 h, unreceptivity and unresponsivity of brainstem reflexes, anesthesia in the last 24 h, hypothermia, anamnesis for barbiturate use, electroencephalogram artefacts, toxic state, and pediatric criteria. All patients underwent Tc-ECD SPECT using a dual-headed camera fitted with a high-resolution low-energy collimator. Images were reconstructed and processed according to standard procedures and interpreted qualitatively by two experienced observers. The presence of spots of residual brain viability was observed in 13 patients: 25% of our patient cohort. The patients with residual viability were younger (aged 30.92+/-17.28 years) in comparison with those with no viability (41.91+/-18.77 years, P<0.031). Considering the eligibility for transplantation, there were 12 of 13 patients in the residual viability group and 31 of 39 in the no viability group (P<0.0001). All patients with spots of brain uptake were monitored daily by Tc-ECD SPECT, and all of them reached the condition of empty skull after one or multiple studies. The opposition to organ donation was observed in six of 13 patients with spots of viable brain tissue and in three of 39 with no signs of residual viability (P<0.001). In patients with confounding factors in whom brain death diagnosis is equivocal, Tc-ECD SPECT is a helpful and safe diagnostic approach, allowing a three-dimensional evaluation of cortical and brainstem viability. It guarantees an unequivocal diagnosis of brain death for patients who are potential candidates for organ donation. The persistence of viable spots of brain tissue was found in 25% of our patients and was more frequent in young patients. This affects the opposition to donation.

Cognitive function and 99mTc-ECD brain SPECT are significantly correlated in patients with primary Sjögren syndrome: a case–control study

Objectives:To assess subclinical central nervous system (CNS) involvement in primary Sjögren syndrome (pSS), by comparing standard brain MRI, in-depth neuropsychological testing and 99mTc-ECD brain single-photon emission computed tomography (SPECT) of...

Reduced Cerebral Blood Flow During Wakefulness In Obstructive Sleep Apnea-Hypopnea Syndrome

To investigate changes in regional cerebral blood flow (rCBF) in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). We compared the 99mTc-ethylcysteinate dimer (ECD) single photon emission computed tomography (SPECT) images of patients with OSAHS with those of age- and sex-matched healthy volunteers. University hospital. Twenty-seven patients with severe OSAHS and 27 healthy volunteers underwent 99mTc-ECD brain SPECT studies. For statistical parametric mapping analysis, all SPECT images were spatially normalized to the standard SPECT template and then smoothed using a 14-mm full-width at half-maximum Gaussian kernel. The Student t test was used for the statistical analysis. The mean age of patients and subjects was 44.3 years (range 31-58). All patients underwent overnight polysomnography. The mean apnea-hypopnea index of patients was 60.4 +/- 17.6 per hour (range 33 -104), indicating severe OSAHS. All patients snored heavily and had daytime sleepiness (mean Epworth Sleepiness Scale score, 10.7 +/- 3.7, range 6-12). Statistical parametric mapping analysis showed that rCBF in patients with OSAHS was significantly reduced in bilateral parahippocampal gyri and in the right lingual gyrus, as compared with that of healthy volunteers (P < 0.05 with false discovery rate correction). Moreover, apnea-hypopnea indexes of patients were negatively correlated with rCBF in the right pericentral gyrus and right cuneus at uncorrected P < 0.001. Our results show the altered rCBF pattern in bilateral parahippocampal gyri, right lingual gyrus, pericentral gyrus, and cuneus in patients with severe OSAHS. These findings may partly explain the deficit in memory, spatial learning, executive function, and attention, which are frequently found in patients with OSAHS.

Abnormal Regional Cerebral Blood Flow in Systemic Lupus Erythematosus Patients With Psychiatric Symptoms

Single-photon emission computed tomography (SPECT) studies have demonstrated decreased regional cerebral blood flow (rCBF) in systemic lupus erythematosus (SLE) patients. However, no study has done voxel-based analysis using statistical parametric mapping (SPM) that can evaluate rCBF objectively, and the relationship between rCBF and psychiatric symptoms has not been well investigated. Using L,L-ethyl cysteinate dimer (99mTc ECD) SPECT and SPM, we aimed to clarify the association of rCBF changes with psychiatric symptoms in SLE patients whose magnetic resonance imaging (MRI) showed no morphological abnormalities. Twenty SLE patients and 19 healthy volunteers underwent 99mTc ECD SPECT. Data were collected from August 2000 to March 2003. SLE was diagnosed according to American College of Rheumatology criteria, and psychiatric symptoms were diagnosed according to ICD-10 criteria. On the basis of the modified Carbotte, Denburg, and Denburg method, the patients were classified into 3 groups: a group with major psychiatric symptoms (hallucinosis, delusional disorder, and mood disorder), a group with minor psychiatric symptoms (anxiety disorder, dissociative disorder, and emotionally labile disorder), and a group without psychiatric symptoms. Gross organic lesions were ruled out by brain MRI. Group comparisons of rCBF were performed with analysis using SPM99. SLE patients without MRI lesions showed decreased rCBF in the posterior cingulate gyrus and thalamus. The reduction in rCBF was overt in patients with major psychiatric symptoms. Our study indicated that SLE patients may have dysfunction in the posterior cingulate gyrus and thalamus and that this may be associated with the severity of psychiatric symptoms.

Perfusion abnormality of the caudate nucleus in patients with paroxysmal kinesigenic choreoathetosis

Previous cerebral blood flow and glucose metabolism studies suggest that the basal ganglia or thalamus is involved in the pathogenesis of paroxysmal kinesigenic choreoathetosis (PKC). However, the underlying cerebral abnormalities in idiopathic PKC have not been elucidated. To localise cerebral perfusion abnormalities in PKC, we performed interictal brain perfusion 99mTc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in PKC patients and in normal controls. Sixteen patients with idiopathic PKC and 18 age- and sex-matched normal controls were included. The patients were de novo diagnosed as having PKC, or had not taken medication for at least 3 months; none of them had structural abnormalities on MRI. Patients had a history of PKC attacks of a duration not exceeding 5 min and starting either on one side or on both sides of the body. These attacks were always induced by a sudden initiation of voluntary movement. PKC attacks were recorded in a hospital after being induced by neurology staff in 13 of the 16 patients. Interictal brain perfusion 99mTc-ECD SPECT was performed in all 16 patients and 18 normal controls. Differences between the cerebral perfusion in the PKC group and the normal control group were tested by statistical parametric mapping. Student's t test was used for inter-group comparisons. Compared with normal controls, patients with idiopathic PKC showed interictal hypoperfusion in the posterior regions of the bilateral caudate nuclei (false discovery rate-corrected P<0.001 with a small volume correction). This study showed that cerebral perfusion abnormality of bilateral caudate nuclei is present in idiopathic PKC.

Combined 99mTc-ECD SPECT and neuropsychological studies in MCI for the assessment of conversion to AD

Identifying pre-clinical Alzheimer's disease (AD) in subjects with mild cognitive impairment (MCI) is a major issue in clinical diagnosis. Establishing a combination of predictive markers from different fields of research might help in increasing the diagnostic accuracy. Aim of this study was to evaluate the potential role of 99mTc-ECD single photon emission computed tomography (SPECT) and memory scores in predicting conversion to AD in MCI subjects. Thirty-one MCI subjects underwent a clinical and neuropsychological examination, and a regional cerebral blood flow (rCBF) SPECT scan at baseline. Subjects had been followed periodically through 2 years in order to monitor the progression of cognitive symptoms. Canonical variate analysis of principal components was able to separate all subjects who converted to AD from those who remained stable, the former being characterized by a specific hypometabolic pattern, involving the parietal and temporal lobes, precuneus, and posterior cingulate cortex. Canonical correlation analysis of combined baseline memory deficits and rCBF SPECT images identified pre-clinical AD with a sensitivity and specificity of 77.8%. The pattern of hypoperfusion 99mTc-ECD SPECT and the severity of memory deficits predict the risk of progression to probable AD dementia in MCI subjects.