Positron emission tomography/computed tomography dual imaging using 18-fluorine flurodeoxyglucose and 11C-labeled 2-ß-carbomethoxy-3-ß-(4-fluorophenyl) tropane for the severity assessment of Parkinson disease.

The value of dual imaging mode for the severity assessment of Parkinson disease (PD) is explored by conducting positron emission tomography computed tomography (PET/CT) double imaging using combined 18-fluorine flurodeoxyglucose (F-FDG) brain metabolism and 11C-2ß-carbomethoxy-3ß-(4-fluorophenyl) tropane (C-CFT) brain dopamine transporter (DAT).A total of 102 patients with PD and 50 healthy people in the control group are enrolled for the PET/CT dual imaging of F-FDG brain metabolism and C-CFT brain DAT. The characteristics of F-FDG PET/CT and C-CFT PET/CT imaging are analyzed by delineating the region of interest. Differences in the glucose metabolism and DAT distribution in the basal ganglia of patients with PD and healthy control group in the PET/CT imaging and the radioactive distribution characteristics of cerebral cortex in glucose metabolism imaging are compared. The characteristics of PET/CT imaging of C-CFT brain DAT in the ganglion region in absorbing C-CFT in different PD groups are analyzed.Compared with the healthy control group, changes in the cerebral glucose metabolism in the PD group mainly occur due to the increased symmetry metabolism of the nucleus of bilateral basal ganglia and the decreased metabolism of the cerebral cortex as shown in the F-FDG PET/CT images. With disease progression, the bilateral parietal, frontal, temporal, and occipital leaves showed different degrees of FDG metabolism. Statistically significant difference is observed for theC-CFT absorption among the caudate nucleus and the anterior, middle, and posterior nuclei of the bilateral basal ganglia of the PD and healthy control groups. In the PD group, the bilateral caudate nucleus and the anterior, middle, and posterior parts of the putamen show decreased DAT distribution. Regardless of unilateral or bilateral symptoms, the DAT distribution in the nucleus of the contralateral basal ganglia and in the posterior part of the nucleus is substantially reduced.PET/CT dual imaging by F-FDG PET/CT combined with C-CFT PET/CT features high application value for the severity assessment of PD.

Multimodal assessment of recovery from coma in a rat model of diffuse brainstem tegmentum injury.

Despite the association between brainstem lesions and coma, a mechanistic understanding of coma pathogenesis and recovery is lacking. We developed a coma model in the rat mimicking human brainstem coma, which allowed multimodal analysis of a brainstem tegmentum lesion's effects on behavior, cortical electrophysiology, and global brain functional connectivity. After coma induction, we observed a transient period (∼1h) of unresponsiveness accompanied by cortical burst-suppression. Comatose rats then gradually regained behavioral responsiveness concurrent with emergence of delta/theta-predominant cortical rhythms in primary somatosensory cortex. During the acute stage of coma recovery (∼1-8h), longitudinal resting-state functional MRI revealed an increase in functional connectivity between subcortical arousal nuclei in the thalamus, basal forebrain, and basal ganglia and cortical regions implicated in awareness. This rat coma model provides an experimental platform to systematically study network-based mechanisms of coma pathogenesis and recovery, as well as to test targeted therapies aimed at promoting recovery of consciousness after coma.

Clarifying associations between cortical thickness, subcortical structures, and a comprehensive assessment of clinical insight in enduring schizophrenia.

BACKGROUND: The relationship between poor insight and less favorable outcomes in schizophrenia has promoted research efforts to understand its neurobiological basis. Thus far, research on neural correlates of insight has been constrained by small samples, incomplete insight assessments, and a focus on frontal lobes. The purpose of this study was to examine associations of cortical thickness and subcortical volumes, with a comprehensive assessment of clinical insight, in a large sample of enduring schizophrenia patients. METHODS: Two dimensions of clinical insight previously identified by a factor analysis of 4 insight assessments were used: Awareness of Illness and Need for Treatment (AINT) and Awareness of Symptoms and Consequences (ASC). T1-weighted structural images were acquired on a 3 T MRI scanner for 110 schizophrenia patients and 69 healthy controls. MR images were processed using CIVET (version 2.0) and MAGeT and quality controlled pre and post-processing. Whole-brain and region-of-interest, vertex-wise linear models were applied between cortical thickness, and levels of AINT and ASC. Partial correlations were conducted between volumes of the amygdala, thalamus, striatum, and hippocampus and insight levels. RESULTS: No significant associations between both insight factors and cortical thickness were observed. Moreover, no significant associations emerged between subcortical volumes and both insight factors. CONCLUSIONS: These results do not replicate previous findings obtained with smaller samples using single-item measures of insight into illness, suggesting a limited role of neurobiological factors and a greater role of psychological processes in explaining levels of clinical insight.

Quantitative assessment on blood-brain barrier permeability of acute spontaneous intracerebral hemorrhage in basal ganglia: a CT perfusion study.

PURPOSE: Blood-brain barrier (BBB) damage aggravates perihematomal edema, and edema volume predicts prognosis independently. But the BBB permeability at the late stage of acute intracerebral hemorrhage (ICH) patients is uncertain. We aimed to assess the BBB permeability of spontaneous basal ganglia ICH using computed tomographic perfusion (CTP) and investigates its relationship with hematoma and perihematomal edema volume. METHODS: We performed CTP on 54 consecutive ICH patients within 24 to 72 h after symptom onset. Permeability-surface area product (PS) derived from CTP imaging was measured in hematoma, "high-PS spot," perihematoma, normal-appearing, hemispheric, and contralateral regions. Hematoma and edema volumes were calculated from non-contrast CT. RESULTS: "High-PS spot" and perihematoma regions had higher PS than the contralateral regions (p < 0.001). Hematoma PS was lower than that in the contralateral regions (p < 0.001). Perihematoma PS of the large-hematoma group was higher than that of the small-hematoma group (p = 0.011). Perihematomal edema volume correlated positively with hematoma volume (ß = 0.864, p < 0.001) and perihematoma PS (ß = 0.478, p < 0.001). Perihematoma PS correlated positively with hematoma volume (ß = 0.373, p = 0.005). CONCLUSIONS: Locally elevated perihematoma PS was found in most spontaneous basal ganglia ICH patients within 24 to 72 h after symptom onset. Perihematoma PS was higher in larger hematomas and was associated with larger edema volume. At this period, BBB leakage is likely to be an important factor in edema formation.

Prognostic Assessment of Aneurysmal Subarachnoid Patients with WFNS Grade V by CT Perfusion on Arrival.

BACKGROUND: The prognosis of patients with aneurysmal subarachnoid hemorrhage (aSAH) depends on their condition on arrival at the hospital. However, a small number of patients recover from an initially poor condition. We investigated the correlation between quantitative measures of computed tomography (CT) perfusion (CTP) on arrival and the outcomes of patients with World Federation of Neurosurgical Society (WFNS) grade V aSAH. METHODS: We performed plain CT, CTP, and CT angiography (CTA) in all patients with aSAH on arrival. Aneurysms were surgically obliterated in patients with stable vital signs and the presence of a brain stem response. We measured the average mean transit time (aMTT) and compared it with the modified Rankin Scale (mRS) score at 1 month. Regions of interest were identified as 24 areas in the bilateral anterior, middle, and posterior cerebral artery territories and 2 areas in the basal ganglia. RESULTS: A total of 57 patients were treated between 2007 and 2014. None of the 21 patients with aMTT >6.385 seconds achieved a favorable outcome, whereas 8 of the 36 patients with aMTT <6.385 seconds did achieve a favorable outcome (P = 0.015). Furthermore, comparing the number of areas showing a mean transit time (MTT) >7.0 seconds among the aforementioned 8 areas and mRS, favorable outcomes were not seen in 24 patients with more than 2 such areas (P = 0.009). CONCLUSION: We cannot expect a favorable outcome for patients with WFNS grade V aSAH with aMTT >6.385 seconds or more than 2 of 8 areas with MTT >7.0 seconds.

Longitudinal Assessment of Motor Recovery of Contralateral Hand after Basal Ganglia Infarction Using Functional Magnetic Resonance Imaging.

We used functional fMRI to study the brain activation during active finger movements at different time points during the recovery phase following basal ganglia infarction. Four hemiplegic patients with basal ganglia infarction were serially evaluated at different time points spanning the acute and chronic phase using fMRI. To evaluate motor recovery, the patients were asked to perform functional tasks arranged in a block design manner with their hand. On follow-up (chronic phase), three patients achieved significant recovery of motor function of affected limbs. Activation of bilateral sensorimotor cortex (SMC) was observed in two of these patients, while activation of cerebellum was observed in all patients. No remarkable recovery of motor function was noted in one patient with left basal ganglia infarction. In this patient, the activation domain was located in SMC of both sides in acute phase and in ipsilateral SMC in chronic phase. Contralateral SMC appears to be involved in the functional rehabilitation following basal ganglia infarction. The cerebellum may act as an intermediary during functional recovery following basal ganglia infarction. The activation domain associated with active finger movement may be bilateral in acute phase; one patient was ipsilateral in the chronic stage.

Assessment of enlarged perivascular spaces and their relation to target organ damage and mild cognitive impairment in patients with hypertension.

BACKGROUND AND PURPOSE: Enlarged perivascular spaces (EPVS) have been recently considered a feature of cerebral small vessel disease. They have been related to aging, hypertension and dementia but their relationship with hypertension related variables (i.e. target organ damage, treatment compliance) and mild cognitive impairment (MCI) is not fully elucidated. Our aims were to investigate the relation between basal ganglia (BG) and centrum semiovale (CSO) EPVS with vascular risk factors, hypertension related variables and MCI. METHODS: In all, 733 hypertensive individuals free of stroke and dementia from the Investigating Silent Strokes in Hypertensives, a magnetic resonance imaging Study (ISSYS) underwent brain magnetic resonance imaging and cognitive testing to diagnose MCI or normal cognitive aging. RESULTS: The numbers of participants presenting high grade (>10) EPVS at the BG and CSO were 23.3% and 40.0%, respectively. After controlling for vascular risk factors, high grade BG EPVS were associated with age (odds ratio 1.68; 95% confidence interval 1.37, 2.06), poor antihypertensive compliance (1.49; 1.03, 2.14) and the presence of microalbuminuria (1.95; 1.16, 3.28), whereas in the CSO only age (1.38; 1.18, 1.63) and male sex were associated with EPVS (1.73; 1. 24, 2.42). MCI was diagnosed in 9.3% of the participants and it was predicted by EPVS in the BG (1.87; 1.03, 3.39) but not in the CSO. This last association was greatly attenuated after correction for lacunes and white matter hyperintensities. CONCLUSIONS: Basal ganglia EPVS are associated with the presence of microalbuminuria and poor adherence to antihypertensive drugs. The BG EPVS relation with MCI is not independent of the presence of other cerebral small vessel disease markers.

Cortical dynamics and subcortical signatures of motor-language coupling in Parkinson's disease.

Impairments of action language have been documented in early stage Parkinson's disease (EPD). The action-sentence compatibility effect (ACE) paradigm has revealed that EPD involves deficits to integrate action-verb processing and ongoing motor actions. Recent studies suggest that an abolished ACE in EPD reflects a cortico-subcortical disruption, and recent neurocognitive models highlight the role of the basal ganglia (BG) in motor-language coupling. Building on such breakthroughs, we report the first exploration of convergent cortical and subcortical signatures of ACE in EPD patients and matched controls. Specifically, we combined cortical recordings of the motor potential, functional connectivity measures, and structural analysis of the BG through voxel-based morphometry. Relative to controls, EPD patients exhibited an impaired ACE, a reduced motor potential, and aberrant frontotemporal connectivity. Furthermore, motor potential abnormalities during the ACE task were predicted by overall BG volume and atrophy. These results corroborate that motor-language coupling is mainly subserved by a cortico-subcortical network including the BG as a key hub. They also evince that action-verb processing may constitute a neurocognitive marker of EPD. Our findings suggest that research on the relationship between language and motor domains is crucial to develop models of motor cognition as well as diagnostic and intervention strategies.

[Potential of helical scan technique in acute cerebral infarction assessment].

The high convenience of data collection by helical scanning, such as making multi planner reformat (MPR) and shortening scan time, means that the technique is widely used to diagnose various body parts. However, non-helical scanning is still a main current for plane brain computed tomography. The possibility of diagnosing acute cerebral infarction by helical scanning MPR was examined. It was found that image degradation in helical scanning had little influence on the physical evaluation of the characteristics of modulation transfer function and the noise power spectrum, etc. In the evaluation of the ischemic change occurring at the early stage made by examination of clinical images, the result was almost equal to that obtained by non-helical scanning, as the reported sensitivity was 52% and the specificity was 95%. This suggested that brain helical scanning MPR might be applied clinically. However, a disadvantage was confirmed as helical scanning had a higher exposure dose than non-helical scanning at the start and end of scanning. The results of this study indicated that helical scanning demonstrates sufficient convenience for the assessment of acute cerebral infarction at the basal nucleus level.

Use of 11C-methionine positron emission tomography in basal germinoma: assessment of treatment response and residual tumor.

INTRODUCTION: Prognosis of germinoma arising in the basal ganglia or thalamus is worse compared to that in the pineal or suprasellar region. One of the reasons for poor prognosis is the difficulty in evaluating the efficacy of treatment by conventional neuroimaging tools. PET STUDIES: The usefulness of (11)C-methionine (MET) positron emission tomography (PET) in monitoring the biological nature of brain tumors has been proved in glioma patients. CASE REPORTS: Herein, we describe MET-PET findings in three cases of germinomas in the basal ganglia or thalamus and discuss the use of MET-PET in the assessment of treatment response and residual tumor for the next treatment strategy. The patients showed transient increase of MET uptake in the lesions after the initial treatment. Although we did not perform histological verification, MET- PET findings suggested that active tumor cells were still alive in the lesions after the initial treatment. MET uptake gradually decreased during the course of intensive therapy in these patients. MET-PET also revealed germinoma invasion in the brain before discernible signal abnormality or mass lesion in conventional magnetic resonance images in two patients. DISCUSSION: Further studies including histological verification and long-term follow-up might validate the use of MET-PET in monitoring the treatment efficacy and evaluation of active residual tumor after the treatment. CONCLUSION: Until we understand what MET uptake truly represents, treatment strategy based on MET uptake must be carefully designed to prevent overtreatment and resultant complications.

[Usefulness of FDG-PET in the diagnosis of patients with chronic severe brain injury]. / Utilidad de la PET con FDG en la valoración del paciente con traumatismo craneoencefálico severo crónico.

INTRODUCTION: To describe the changes in cerebral glucose metabolism after a severe traumatic brain injury (TBI), at the beginning of the rehabilitation, to analyze its diagnostic agreement with morphologic neuroimaging technologies (MR/CT) and to correlate the neuroimaging findings with the intensity of the TBI and the functional ability for daily activities. MATERIAL AND METHODS: Prospective study of 55 patients who had sustained a severe TBI (GCS < or = 8) by means of 18F-FDG PET and MR/CT. The agreement between anatomical and functional neuroimagen studies was measured. Correlation between cerebral injury severity in neuroimaging, clinical functional evaluation assessed with Barthel-M Index and GCS were tested. RESULTS: 100 % of patients showed changes in cerebral metabolism, being the thalamus the area more frequently affected. 60 % of patients showed injuries in MR/CT, more frequently in frontal areas. The agreement for the diagnosis of pathology between morphologic and functional neuroimagen was very low. The TBI severity showed significant statistical correlation with the degree of cerebral metabolism and the level of disability. CONCLUSIONS: 18F-FDG PET allows to know the cerebral glucose metabolism at the beginning of the rehabilitation, being correlated with the TBI severity and the level of patient's disability for daily activities. 18F-FDG PET diagnoses major number of injuries that traditional neuroimaging and demonstrates a high thalamic vulnerability, with injuries in up to 76 % of patients with severe TBI.

[Improvement in accuracy of quantitative assessment of the regional cerebral blood flow with 99mTc-ECD].

Mean cerebral blood flow (mCBF) in the slice including the basal ganglia (reference slice) is necessary for the quantification of regional CBF using Patlak plot and BUR methods on 99mTc-ECD cerebral perfusion SPECT. The mCBF was calculated from the mean counts of this slice. A region of interest (ROI) has been manually set on the reference slice to obtain the mean counts (manual ROI method). However, there was large variability observed in the value of rCBF in this method. We developed a 3DSRT method for improving the accuracy of the mean counts in the reference slice and evaluated the difference between the value of rCBF on manual ROI method and that on 3DSRT method in consecutive 11 patients with cerebral vascular disease. Difference in the value of mean counts of the reference slice was distributed within the 2 standard deviations (SD) with Blant-Altman analysis in 9 of 11 patients. Significant difference in the value of mean counts between two methods was observed in 2 of 11 patients. 3DSRT method is superior accuracy to the manual ROI method in the evaluation of the counts in the ROI. Lower accuracy in manual ROI method, therefore, results in the difference of the value of mean counts. 3DSRT method provides high accuracy with the various quantitative methods for the evaluation of rCBF using 99mTc-ECD.

Assessment of image quality of a standard and three dose-reducing protocols in adult cranial CT.

The purpose of this study was to analyze the effect of various tube current settings (mAs) and optimize the image quality and dose for adult cranial CT protocol. Sixty adult patients who underwent a cranial CT scanning for different indications were subdivided into three subgroups. Subjective image and noise quality scores and quantitative noise measurements were selectively studied on three reference levels (cerebellar, basal ganglia and centrum semiovale levels). For each subgroup, only one level was studied. Head circumference (HC) and the maximum anteroposterior diameter (MAPD) of each patient were measured. At 50% decreased dose protocol, there was no poor quality score at any level. At nearly 60% decreased dose protocol, the incidence of poor quality scores was much higher at the cerebellar level than at the other two levels. For the same protocol number, quantitative noise measurements were higher at the cerebellar level than the other two supratentorial levels. The correlation was found to be significant between HC, MAPD and quantitative noise measurements, and there was a non-significant correlation between HC and subjective noise scores. In adult cranial CT, depending on the level, a dose reduction of up to 60% may be possible while maintaining image quality.

Reliability assessment of computerized tomography scanning measurements in intracerebral hematoma.

OBJECT: As one of the aspects of the International Surgical Trial in Intracerebral Haemorrhage (STICH), prerandomization computerized tomography (CT) scans were collected. In the present study the authors determined the inter-and intraobserver variability of various parameters pertinent to CT scans obtained in patients with intracerebral hematomas (ICHs). METHODS: A protocol was devised to analyze CT scans in a uniform and systematic manner. Each observer evaluated the same set of scans twice, with a minimum 2-month interval between assessments. In addition to noting the side and the sites of involvement, the observers measured the scale present on the scan itself and the length, breadth, height, and depth of the spontaneous ICH as well as the midline shift. The intraclass correlation was very high (kappa 0.8-1) for the measurements of volume, depth, and midline shift. Good interobserver agreement (kappa 0.8-1) was demonstrated with regard to involvement of basal ganglia or thalamus, presence of intraventricular extension, and the side of the hematoma. Agreement was substantial (kappa 0.61-0.8) with regard to identifying primary involvement of particular lobes. Agreement was moderate (kappa 0.41-0.6) on the presence or absence of hydrocephalus. When comparing the first and the second sets of readings, the intraobserver agreement was good (80-100%). CONCLUSIONS: The study quantifies the degree of inter- and intraobserver agreement regarding evaluation of CT scans in patients with ICH when conducted in accordance with a set protocol.

Assessment of the CO2 response by means of non diffusible contrast media and angio-CT in patients with cluster headache.

We analyzed the possibility of assessing functional vasomotor changes by means of Arm-Brain Circulation Time (rABCT) and Vascular volume images (Vv) obtained with Angio-CT, in basal condition and following CO2 inhalation, in a sample of 48 patients with cluster headache. CO2 inhalation resulted in the appearance of local changes, which were detected in 28 regions. Analysis by indicator images of Vv-dependent rABCT distribution showed two main patterns: abnormal rABCT mostly evident at the smallest Vv pixels and abnormal rABCT dependent on abnormal Vv distribution. The former pattern was linked to abnormality at the circle of Willis; the latter to abnormal local vasomotor responses. Patients with cluster headache showed both patterns, which prompted us to conclude for the presence of low-degree stenosis in carotid arteries and vasomotor instability in peripheral brain vessels.

[An assessment of the thalamocortical sensory pathway based on small infarcts in the corona radiata on CT].

Although lacunar syndrome is relatively commonly encountered in patients with a lacunar infarct in the deep cerebral white matter, the responsible lesions are often unidentified. By examining eight patients with lacunar syndrome who had small infarcts in the deep cerebral white matter, an attempt was made to determine the position and distribution of the sensory pathway on brain CT at the level of the splenium of the corpus callosum. When the distance from the frontal crista to the superior saggital sinus sulcus was defined as 1.0, the position of the corticospinal tract was located in the portion from 0.45 to 0.49 and that of the sensory pathway in the portion from 0.49 to 0.53. These data indicated that the position of the sensory pathway was just behind the corticospinal tract and the distribution was very narrow at this level. The results of this assessment revealed that lacunar infarcts in the deep cerebral white matter were liable to cause sensorimoter syndrome more than pure sensory stroke.

Single photon emission computerized tomography assessment of cerebral dopamine D2 receptor blockade in depression before and after sleep deprivation--preliminary results.

The antidepressant properties of total sleep deprivation (TSD) have been well established. There is some evidence that TSD may improve depression by altering central dopamine (DA) function. We therefore studied five depressed TSD responders and five TSD nonresponders after sleep and after TSD and five controls after sleep with IBZM single photon emission computerized tomography (SPECT). Responders showed a significant decrease (Wilcoxon--test p < 0.05) of relative basal ganglia D2 receptor occupancy after TSD compared to nonresponders (change score responders versus nonresponders p < 0.05, U-test). The data are interpreted as a sign of an enhanced DA release in responders. The results confirm previous hypotheses of dopaminergic involvement in the therapeutic action of TSD and indirectly support a dopamine hypotheses of depression.

The role of positron emission tomography in the assessment of human neurotransplantation.

Positron emission tomography (PET) using tracers of the dopaminergic system has been used to measure striatal function in a small number of parkinsonian patients undergoing neurotransplantation procedures. Some postoperative scans have shown an unequivocal increase in presynaptic dopaminergic function at the graft site, providing evidence of graft survival independent of clinical assessment. Combined PET and magnetic resonance imaging (MRI) images provide the facility to explore the relationship between graft placement, survival and clinical efficacy.