Brain Single Photon Emission Computed Tomography Imaging in Landau-Kleffner Syndrome

Summary: Five right–handed children with Landau-Kleffner syndrome (LKS) who had disease onset between the ages of 3 and 9 years were studied with EEG and single-photon emission computed tomography (SPECT) before and, in four cases, after 6 months of corticosteroid treatment. EEG findings included both focal and generalized spikes as well as spike-wave discharges with bilateral temporal predominance. These increased markedly during sleep in 1 child, and continuous spike-and-wave complexes appeared during slow-wave sleep in another patient. Neuropsychological testing demonstrated verbal auditory agnosia. Magnetic resonance imaging (MRI) was performed in 4 children and was normal. Brain SPECT imaging demonstrated abnormal perfusion in the left temporal lobe in all patients. The response to corticosteroid therapy was mixed. Our findings reinforce the concept that LKS is a functional disease affecting the language-dominant brain areas. We conclude that SPECT imaging may be of diagnostic assistance in the evaluation of this syndrome of unknown etiology.     

Functional neuroimaging strategy in temporal lobe epilepsy: a comparative study of 18FDG-PET and 99mTc-HMPAO-SPECT.

We performed 99mTc-hexamethylpropyleneamineoxime-single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose-positron emission tomography (PET) in 20 epileptic patients with well-lateralized temporal electroencephalographic focus, normal computed tomographic scan, and brain magnetic resonance imaging (MRI) either normal (n = 10) or showing nonspecific changes in the epileptogenic temporal lobe (n = 10). In patients with a normal MRI, PET exhibited focal hypometabolism in 80%, whereas SPECT showed corresponding hypoperfusion in only 20%. In patients with an abnormal MRI, PET and SPECT yielded 100% and 90% sensitivity, respectively. The metabolic and regional cerebral blood flow disturbances were topographically concordant with electroencephalographic and MRI findings in all these patients. Only patients with a large and pronounced hypometabolism on PET images exhibited hypoperfusion on SPECT. Spatial resolution appeared to be the critical factor responsible for the higher sensitivity of PET. However, this superiority of PET did not prove clinically useful in patients whose SPECT was abnormal, particularly when brain MRI showed nonspecific changes in the epileptogenic temporal lobe.     

Qualitative and quantitative imaging of the hippocampus in mesial temporal lobe epilepsy with hippocampal sclerosis

MR imaging allows the in vivo detection of hippocampal sclerosis (HS) and has been instrumental in the delineation of the syndrome of mesial temporal lobe epilepsy with HS (mTLE-HS). MR features of HS include hippocampal atrophy with an increased T2 signal. Quantitative MR imaging accurately reflects the degree of hippocampal damage.Ictal single photon emission computed tomography (SPECT) in mTLE-HS shows typical perfusion patterns of ipsilateral temporal lobe hyperperfusion, and ipsilateral frontoparietal and contralateral cerebellar hypoperfusion. Interictal 18fluoro-2-deoxyglucose positron emission tomography (PET) shows multiregional hypometabolism, involving predominantly the ipsilateral temporal lobe. 11C-flumazenil PET shows hippocampal decreases in central benzodiazepine receptor density. Future strategies to study the etiology and pathogenesis of HS should include longitudinal MR imaging studies,MR studies in families with epilepsy and febrile seizures, stratification for genetic background, coregistration with SPECT and PET, partial volume correction and statistical parametric mapping analysis of SPECT and PET images.     

SPECT abnormalities in Landau-Kleffner syndrome

Five right-handed children with acquired aphasia elipepsy syndrome (Landau-Kleffner, LKS), were investigated with 99^m TcHMPAO single photon emission computed tomography (SPECT) and the results were correlated with their EEGs and clinical history. The childrens' ages ranged from 2 to 5 years and the aphasia had been present for 6 to over 12 months. No clinical seizure had ever been onserved in the younger two children and their waking EEGs showed infrequent central spikes. Both children had areas of low intensity on SPECT, involving the left temporal lobe in one and the right temporal lobe in the other, which has also been reported in children with congenital dysphasia who have normal EEGs. The three older children presented with frequent generalized seizures, with the aphasia occurring 3–6 months later. The SPECT scans in these children were performed either in the ictal state, or when electrographic seizure activity was very frequent on EEG. All three children had hyperintense foci on SPECT involving the left posterior temporal region corresponding to Wernickes area. We conclude that LKS may be initially a unilateral seizure disorder of Wernickes area, with EEG discharges in the contralateral hemisphere representing propagation from the unilateral focus.     

Functional Brain Imaging of a Catatonic Type of Schizophrenia: PET and SPECT Studies

Abstract: A brain imaging study was conducted in the case of a catatonic type of schizophrenia (DSM-IIIR) by applying (i) positron emission tomography (PET) and (ii) single photon emission computed tomography (SPECT). A PET study using [¹⁸]-2-fluoro-2-deoxy-D-glucose revealed a lower glucose utilization in the dorsal frontal and parietal lobes of both cerebral hemispheres. Correlative SPECT studies using [¹²³I]-iodoamphetamine showed a diminished regional cerebral blood flow in similar regions of the cerebral hemisphere. A three-dimensional volume rendering method of the SPECT images (TITAN) identified the dorsal region of the fronto-parietal lobe as the most severely affected region. These patterns of deficits implicated the role of the dorsal frontal and parietal lobes in the pathogenesis of catatonic syndromes.     

Disparity of perfusion and glucose metabolism of epileptogenic zones in temporal lobe epilepsy demonstrated by SPM/SPAM analysis on 15O water PET, [18F]FDG-PET, and [99mTc]-HMPAO SPECT

PURPOSE: To elucidate uncoupling of perfusion and metabolism and its significance in epilepsy, 15O water and 18F fluorodeoxyglucose (FDG) positron emission tomography (PET) and Tc-99m hexamethyl-propyleneamine-oxime (HMPAO) single-photon emission computed tomography (SPECT) were examined by SPM (statistical parametric mapping) and quantitation by using SPAM (statistical probabilistic anatomic map). METHODS: [15O]water and [18F]FDG-PET, and [99mTc]-HMPAO SPECT were performed in 25 patients (SPECT in 17 of 25) with medial temporal lobe epilepsy. For volume of interest (VOI) count analysis, the normalized counts using VOI based on SPAM templates of PET and SPECT were compared with those of the normal controls. Perfusion or metabolism was found abnormal if the Z score was >2 for each VOI. For SPM analysis, the differences between each patient's image and a group of normal control images (t statistic for p < 0.01) on a voxel-by-voxel basis were examined to find significant decreases in perfusion or metabolism. RESULTS: With SPAM VOI count analysis, areas of hypoperfusion were found in 13 patients in the epileptogenic temporal lobes by [15O]water PET and areas of hypometabolism in 21 patients by [18F]FDG-PET. With voxel-based SPM analysis, the epileptogenic zones were localized in 15 by [15O]water PET and in 23 patients by [18F]FDG-PET. The localization by [15O]water PET was concordant with that of [18F]FDG-PET. The areas of hypoperfusion on [15O]water PET were absent or smaller than the areas of hypometabolism on [18F]FDG-PET. Interictal [99mTc]-HMPAO SPECT revealed the hypoperfused zones in seven of 17 patients on visual assessment. CONCLUSIONS: SPAM VOI count and SPM analysis of [15O]water and [18F]FDG-PET and [99mTc]-HMPAO SPECT revealed that in the same patients, the areas of hypoperfusion were concordant with but smaller than the areas of hypometabolism. Discordance of perfusion and metabolic abnormalities represents an uncoupling of perfusion and metabolism in the epileptogenic zones, and this might explain the lower diagnostic accuracy of perfusion imaging in temporal lobe epilepsy.     

Ratio-images calculated from interictal positron emission tomography and single-photon emission computed tomography for quantification of the uncoupling of brain metabolism and perfusion in epilepsy

PURPOSE: Image processing techniques were applied to interictal positron emission tomography (PET) and single-photon emission computed tomography (SPECT) brain images to aid in the localization of epileptogenic foci by calculating a functional image that represents the degree of coupling between perfusion and metabolism. Uncoupling of these two functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and has the potential to serve as a diagnostic measure for localization in other areas as well. METHODS: Interictal PET ((18)F-FDG) and interictal SPECT ((99m)Tc-HMPAO) scans were acquired from 11 epilepsy patients. The metabolism and perfusion images were three-dimensionally spatially registered, and a functional ratio-image was computed. These functional maps are overlaid onto a three-dimensional rendering of the same patient's magnetic resonance imaging anatomy. RESULTS: In all patients, an average uniform perfusion-to-metabolism ratio showed approximately constant values throughout most of the whole brain. However, the epileptogenic area (confirmed on surgery) demonstrated an area of elevated perfusion/metabolism in the grey matter. CONCLUSIONS: Although hypometabolism in the PET image was observed in most of these patients, the calculation of a functional ratio-image demonstrated localized foci that in some cases could not be observed on the PET image alone. The ratio-image also yields a quantitative measure of the uncoupling phenomenon.     

A case of moyamoya disease presenting with chorea

Case report We describe a 15-year-old girl with moyamoya disease whose initial manifestation was chorea-like involuntary movements. T2-weighted magnetic resonance imaging showed high signal intensity lesions in the left frontal lobe, right parieto-occipital lobes, and frontal subcortical white matter. Single-photon emission computed tomography (SPECT) showed diffuse hypoperfusion of the whole brain. Bilateral direct and indirect cerebrovascular bypass surgeries were performed. Chorea disappeared 2 days after the surgery. Follow-up SPECT demonstrated increased cerebral perfusion in the bilateral frontal, temporal, and parietal regions.Conclusions Chorea accompanied with moyamoya disease can be properly managed by revascularization surgery. Moyamoya disease should be remembered as being one of the differential diagnoses of chorea, which is treatable by surgery.     

The use of SPECT and PET in routine clinical practice in epilepsy

PURPOSE OF REVIEW: The aim of this article is to give a subjective review of the usefulness of single photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging in clinical practice in epilepsy for 2007. RECENT FINDINGS: Both ictal perfusion SPECT and interictal fluorodeoxyglucose PET can provide new information in the presurgical evaluation of intractable partial epilepsy. These functional imaging modalities reflect dynamic seizure-related changes in cerebral cellular functions. Although asymmetry of fluorodeoxyglucose PET metabolism has been useful to localize the epileptic temporal lobe, which tends to be more hypometabolic than the contralateral one, both frontal lobes are more hypometabolic than the epileptic temporal lobe, and may represent a region of 'surround inhibition'. Due to its low temporal resolution, ictal perfusion SPECT hyperperfusion patterns often contain both the ictal onset zone and propagation pathways. These patterns often have a multilobulated 'hourglass' appearance. The largest and most intense hyperperfusion cluster often represents ictal propagation, and does not always need to be resected in order to render a patient seizure free. SUMMARY: Optimized interictal FDG-PET and ictal perfusion SPECT as part of a multimodality imaging platform will be important tools to better understand the neurobiology of epilepsy and to better define the epileptogenic, ictal onset, functional deficit and surround inhibition zones in refractory partial epilepsy.     

Ictal SPECT and interictal PET in the localization of occipital lobe epilepsy

PURPOSE: To compare the localizing value of ictal single photon emission computed tomography (SPECT) and interictal fluorodeoxyglucose-positron emission tomography (FDG-PET) in refractory occipital lobe epilepsy. METHODS: Six patients who underwent surgery for refractory epilepsy associated with pathology in the occipital lobe were retrospectively selected from records of the Austin & Repatriation Centre Comprehensive Epilepsy Programme. Interictal SPECT and PET and ictal SPECT were obtained by standard methods. All studies were read by a nuclear medicine expert blinded to clinical data except the diagnosis of epilepsy. RESULTS: Ictal SPECT showed unilateral occipital hyperperfusion in five of six cases often accompanied by temporal lobe hyperperfusion. These patterns were seen in cases with or without magnetic resonance imaging (MRI) abnormality. Interictal SPECT was not localizing in any case, in contrast to PET, which showed occipital hypometabolism in three of five studies. CONCLUSIONS: Ictal SPECT can provide novel localizing data in MRI-negative occipital lobe epilepsy. Interictal PET can provide useful localizing information, but its role in providing novel information was not demonstrated. Interictal SPECT is useful only as a baseline to aid in interpretation of ictal studies.     

A new disorder of praxis in neurodegenerative disease that may be part of Alzheimer's disease

Apraxia is a well-known disorder of praxis and is caused mainly by damage to the left parietal lobe. We presented two cases of neurodegenerative disease with a distinct disorder of praxis, predominantly involving left parietal lobe. While both patients could understand what they should do, they were not able to initiate action and often stopped during execution of actions. They had no apraxia and no temporal and spatial errors on praxis. Magnetic resonance imaging of both patients showed atrophy of the left parieto-occipital and temporo-occipital lobes, and single photon emission computed tomography showed hypoperfusion in the same lobes. Moreover, one of our cases, using [11C] PIB PET, demonstrated increased uptake in the cerebral cortices, suggesting Alzheimer's disease. The symptoms described are different from other disorders of praxis and similar to bradyphrenia or freezing.     

Arteriovenous malformation associated with moyamoya disease

The first case of a child with an arteriovenous malformation (AVM) associated with moyamoya disease is reported. The patient presented ischemic symptoms and underwent isdirect bypass surgery on both sides when she was 5 years old. Four years later she suffered from headache, and a small AVM of the left frontal lobe associated with the moyamoya vessels was detected. Single photon emission computed tomography (SPECT) was performed at age 11 and demonstrated low local cerebral blood flow (CBF) in the left frontal lobe and right temporal lobe, although the revascularization after the bypass surgery seemed to be effective, as judged on pancerebral angiography. We feel that brain ischemia due to the moyamoya disease may have played a causative role in the development of the AVM.     

局灶性难治性颞叶癫痫全脑葡萄糖代谢特点

目的 探讨局灶性难治性颞叶癫痫全脑葡萄糖代谢特点。方法 回顾性分析2017年1~12月行发作间期18FDG-PET/CT检查的23例局灶性难治性颞叶癫痫的影像学资料。将PET图像导入MIM neuro软件,软件自动分析癫痫病人葡萄糖代谢水平与正常人群葡萄糖代谢的差异,各脑区差异结果以Z-Score值显示,分析颞叶癫痫病人全脑葡萄糖代谢特点。结果 术后病理为脑皮质发育不良22例,节细胞胶质瘤1例;病灶位于左侧颞叶16例,右侧颞叶7例。除颞叶呈葡萄糖低代谢改变外,还存在同侧海马、海马旁回、岛叶、杏仁核、颞叶岛盖以及双侧小脑半球葡萄糖代谢不同程度减低;对侧颞叶、额叶、顶叶、顶上小叶以及角回葡萄糖代谢不同程度增高。结论 颞叶癫痫具有一定葡萄糖代谢特点,其特定的葡萄糖代谢特点有助于更加精准的癫痫术前定位及其病理特征的分析。     

发作间期PET对难治性颞叶癫痫的诊断价值

目的分析18例颞叶癫痫患者的正电子发射断层扫描(PET)结果.方法 18例难治性癫痫患者,根据临床症状、脑电图/录像脑电监测(EEG/VEEG)、MRI海马相和单光子发射计算机体层摄影(SPECT)检查诊断为颞叶癫痫.均进行PET检查,结果有16例显示不同程度的颞叶前中部和(或)内侧部的低代谢区域.所有患者均在手术显微镜下采用显微外科技术进行手术,其中右侧颞叶癫痫16例行标准前颞叶及海马杏仁核切除术,左侧颞叶癫痫2例行选择性海马杏仁核切除术.结果随诊观察6～26个月,按照Engel的疗效判断标准,结果I级(癫痫发作消失)11例,II级(极少发作)4例,III级(发作减少75%以上)2例,IV(无改变)1例.结论对于临床上怀疑为颞叶癫痫而上述常规检查方法不能明确癫痫灶者,PET能更好地帮助诊断.     

A case of Kleine-Levin syndrome examined with SPECT and neuropsychological testing

A case of Kleine-Levin syndrome with typical periodic hypersomnia and bulimia was diagnosed. On examination with single photo emission tomography (SPECT) (CERETEC) during a relapse period and 2 weeks later there was marked cortical hypoperfusion of the frontal and temporal lobes, especially on the left side as well as in the right parietal lobe. Neuropsychological testing performed 1 week after a relapse showed a reduction in encoding to memory function of verbal learning indicating neocortical damage of the left fronto-temporal region. A follow-up 2 months later after the patient had spontaneously recovered showed only a slight left fronto-temporal disturbance. CT and MRI of the brain were normal although the MRI showed a large and asymmetric mamillary body. Neuropsychological testing 6 years after recovery showed pronounced reduction in short-time verbal and visual memory. Seven years after recovery SPECT demonstrated a normalized frontal perfusion but still a slight hypoperfusion in the left temporal lobe. Our results correlate to autopsy findings in two cases described previously.     

Retrospective study on PET–SPECT imaging in a large cohort of myotonic dystrophy type 1 patients

The aim was to study brain involvement in myotonic dystrophy type 1 by single photon emission tomography (SPECT) and positron emission tomography (PET). 58 DM1 patients were subjected to SPECT; 17 to both SPECT and PET. SPECT patients were grouped as ‘normally perfused’ and ‘abnormally perfused’; PET patients as ‘normal performers’ and ‘abnormal performers’. To quantify hypoperfusion and/or hypometabolism, we used a semi-quantitative scale. To localize focal hypoperfusion/hypometabolism, nine cerebral areas of involvement were identified. The Chi-square, Wilcoxon, McNemar tests were used for statistics. SPECT showed abnormalities in 52/58 patients. PET showed an abnormal glucidic uptake in 15/17. Hypoperfusion was mild/moderate in 50/58 patients, mostly involving the left supratentorial areas. Abnormal glucidic uptake was mainly observed in the left frontal lobe. Abnormalities in blood perfusion and/or glucose metabolism are frequent in DM1. These abnormalities involve the left more often than the right hemisphere, the frontal lobe more than other lobes. Such abnormalities are more often cortical than subcortical.     

MRI and SPECT in influenzal encephalitis.

Repeated magnetic resonance imaging studies were performed in a 22-month-old boy with influenzal encephalitis. T2-weighted magnetic resonance images disclosed multifocal hyperintense areas in the cortex and subcortical white matter of the left frontal, temporal, parietal, and right frontal lobes. 123I single photon emission computed tomography (SPECT) brain images demonstrated decreased uptake in the same regions. SPECT revealed larger areas of decreased uptake as compared with magnetic resonance imaging. One year after the onset of encephalitis, these brain lesions continue to be observed, although the patient has no apparent neurologic sequelae.     

Mesial temporal lobe epilepsy with lateral temporal lobe abnormalities in magnetoencephalography and glucose metabolism.

Magnetoencephalography (MEG) and positron emission tomography (PET) revealed abnormal findings in the lateral temporal lobe of a 22 year old female with mesial temporal lobe epilepsy. Electroencephalography identified the epileptogenic focus in the left mesial temporal lobe and standard anterior temporal lobectomy resulted in a good surgical outcome. These discrepancies can be explained by the presence of anatomical and functional pathways between the mesial and lateral temporal structures, or pathophysiological abnormalities in both the mesial and lateral temporal lobes. Careful evaluation is necessary for analysis of MEG and PET findings in patients with temporal lobe epilepsy.     

Glucose utilization in the temporal cortex of affectively ill patients: positron emission tomography

As temporal lobe dysfunction has been postulated in the affective disorders, the authors investigated glucose utilization in the temporal lobes of 13 affectively ill patients in comparison with 18 normal volunteer controls and 17 previously reported schizophrenic patients, following injections of fluorine 18-2-deoxy-D-glucose (FDG) during somatosensory stimulation to the right forearm. Using a boundary-finding algorithm to outline each temporal lobe, maximum glucose use relative to maximums elsewhere in the same positron emission tomography (PET) slice were calculated. In a small group of moderately to severely depressed patients, this relative measure was significantly reduced in the right (with a similar trend in the left) temporal lobe compared to normal volunteers and the other comparison groups. The lack of a significant increase in glucose utilization, measured either as a maximum or in relation to other areas in the PET scan slice, suggests that a temporal lobe activation or a seizure-like process is not generally occurring during active depressive phases of the illness.     

Relationship of nonlinear analysis,MRI and SPECT in the lateralization of temporal lobe epilepsy

OBJECTIVES: The purpose of this study was to investigate the correlation of lateralization by nonlinear analysis, magnetic resonance imaging (MRI) and interictal single-photon emission computed tomography (SPECT) in patients with temporal lobe epilepsy. METHODS: Twenty-three patients (7 males, 16 females) were examined by MRI, interictal SPECT and EEG. Nonlinear dynamic properties of neuronal networks were estimated by calculating correlation dimensions on interictal EEG signals and corresponding surrogate data. Lateralization was detected based on the criteria introduced in this study. Concordance rates of the results among the three methods were compared. RESULTS: Epileptogenic foci were shown in the temporal areas in 21 patients using the nonlinear method (8 left, 2 right, 11 both), while 20 patients showed abnormalities in temporal lobes on MR images (13 left, 5 right, 2 both). Low cerebral blood flows of the temporal lobes were detected in all patients (11 left, 8 right, 4 both). Completely concordant lateralization was observed in 8 patients (35%) for the nonlinear method and MRI, in 9 patients (39%) for the nonlinear method and SPECT, and in 10 patients (43%) for MRI and SPECT. There were no significant differences among the concordance rates for these different methods. CONCLUSIONS: Our results revealed that correlation dimension is useful for differentiating dynamic properties of neuronal networks in the interictal state, and can provide informative data for localizing epileptogenic foci in epileptic patients. Therefore, the present nonlinear method is recommended for use with patients during presurgical evaluation.