113 research outputs found
1 H-MR-spektroskopische Bestimmung der zerebralen Glutamat- und Glutaminkonzentration bei Patienten mit einer Demenz vom Alzheimer-Typ
Die in vivo MR-Protonenspektroskopie (1H-MRS) ist ein nichtinvasives Verfahren, das die Untersuchung biochemischer Substanzen beim Lebenden ermöglicht. In einer prospektiven Studie wurden Patienten, die an einer Demenz vom Alzheimer-Typ (DAT) litten, und altersentsprechende Probanden mit der 1H-MRS untersucht. Im Hirngewebe wurden Konzentrationen von MolekĂŒlen bestimmt, die Aussagen ĂŒber die zellulĂ€re Zusammensetzung ermöglichen. Das Hauptinteresse galt der Untersuchung von Glutamat und Glutamin, da ein Ăberangebot des Neurotransmitters Glutamat im synaptischen Spalt möglicherweise fĂŒr die Neurodegeneration beim M. Alzheimer mitverantwortlich ist. Bei 29 Patienten mit einer DAT sowie 19 Probanden wurden zwei Volumina in Kortex und Marklager des Parietallappens bei 1,5 Tesla MagnetfeldstĂ€rke mit einer PRESS-Sequenz (TE = 22 ms, TR = 3 s) untersucht. Die Patienten waren kognitiv leicht bis mittelschwer beeintrĂ€chtigt (Mini Mental State Examination, MMSE, 11-27 Punkte). Die quantitative Auswertung der Spektren erfolgte nach der "phantom replacement method" mit dem Softwareprogramm LCModel. Als Kriterium fĂŒr die ZuverlĂ€ssigkeit der Konzentrationsangaben diente die vom Programm als %SD-Wert angegebene Auswertegenauigkeit der Einzelmessungen. Neben dem Glutamat- und Glutamingehalt wurden der Liquorgehalt im kortikalen Messvolumen und die Konzentrationen der MolekĂŒle N-Acetyl-Aspartat und N-Acetyl-Aspartyl- Glutamat (tNAA), myo-Inositol (mI), Kreatin und Kreatinphosphat (tCr) sowie der cholinhaltigen Substanzen (tCh) bestimmt. Bei den Patienten konnten 25 aussagekrĂ€ftige Spektren aus der Rindenregion und 19 aus dem Marklager des Parietallappens gemessen werden, bei den Probanden 17 Kortex- und 13 Marklager-Spektren. Glutamat und Glutamin können mit der in vivo-Spektroskopie wegen ihrer sich ĂŒberlappenden Resonanzen nicht separat bestimmt werden und wurden deshalb als âGlxâ zusammengefasst. Der Glx-Gehalt betrug in der Rindenregion bei den Patienten im Durchschnitt 15,48 ± 5,15 mmol/l, bei den Probanden 13,98 ± 3,14 mmol/l. Die um 11% höhere Konzentration bei den Patienten war nicht signifikant. Die Glx-Konzentrationen im Marklager betrugen 8,16 ± 3,79 mmol/l bei den Patienten und 8,14 ± 3,71 mmol/l bei den Probanden. Nach dem Kriterium der %SD war die ZuverlĂ€ssigkeit der Konzentrationsbestimmung von Glutamat und Glutamin eingeschrĂ€nkt, was auf die protonenspektroskopischen Eigenschaften von Glutamat und Glutamin zurĂŒckzufĂŒhren ist. Sie erzeugen wegen ihrer gekoppelten Resonanzen breite und mehrgipflige Protonensignale, die wegen der resultierenden niedrigen Signalamplitude fĂŒr LCModel von MakromolekĂŒlresonanzen oder von Artefakten, die durch ungenĂŒgende WasserunterdrĂŒckung entstehen, schwierig abzugrenzen sind. Die %SD-Werte der Einzelmessungen von tNAA, mI, tCr und tCh waren gering, die Messergebnisse können daher als zuverlĂ€ssig angesehen werden. Die tNAA-Konzentrationen in beiden Gruppen unterschieden sich weder in der grauen noch in der weiĂen Substanz signifikant voneinander. Im Hirnrindenvolumen zeigte sich bei den Patienten jedoch eine positive Korrelation von tNAA und MMSE-Ergebnis, also eine Reduktion von tNAA mit zunehmenden kognitiven EinbuĂen. Dies spricht fĂŒr eine Abnahme des neuronalen Volumenanteils mit fortschreitender Erkrankung. Der durchschnittliche myo-Inositolgehalt im Marklagervolumen lag in der Patientengruppe um 20% höher als bei den Probanden. Der Unterschied erreichte jedoch kein Signifikanzniveau (p = 0,09). Im Rindenvolumen war die mittlere myo-Inositolkonzentration bei den Patienten um 7% höher als in der Kontrollgruppe, auch hier war der Unterschied nicht signifikant. Der nichtsignifikante myo-Inositolanstieg lĂ€sst sich als mĂ€Ăige entzĂŒndliche oder reaktive Gliaproliferation interpretieren. Die tCr-Konzentrationen in beiden Gruppen unterschieden sich nicht, jedoch bestand bei den DAT-Patienten eine positive Korrelation des tCr-Gehalts mit der MMSE-Punktzahl in der grauen Substanz des Parietallappens, die Konzentration nahm also mit zunehmendem Schweregrad der Demenz ab. Bei der durchschnittlichen tCh-Konzentration bestanden keine Gruppenunterschiede in den untersuchten Regionen. Die Patienten wiesen eine signifikante Zunahme des mittleren Liquoranteils um 16% im kortikalen Volumen auf. Dies ist als kortikale Hirngewebeatrophie in frĂŒhen und mittleren Stadien der DAT zu werten. WĂ€hrend die in vivo-Konzentrationen von tNAA, mI, tCr und tCh zuverlĂ€ssig bestimmt werden konnten, war die Messung von Glutamat und Glutamin bei 1,5 T mit technischen Schwierigkeiten verbunden. Wegen der hohen Standardabweichungen konnte aus dieser Untersuchung keine gesicherte Aussage zu einer möglichen KonzentrationsĂ€nderung dieser AminosĂ€uren bei der DAT abgeleitet werden. Es ist zu erwarten, dass hier durch MR-GerĂ€te mit 3 T FeldstĂ€rke sowie durch den Einsatz der parallelen Bildgebung ein erheblich höheres Signal/Rausch-VerhĂ€ltnis und damit genauere Ergebnisse erzielt werden können.Proton magnetic resonance spectroscopy (1H-MRS) is a noninvasive tool for the examination of neurochemistry in vivo. The aim of the present prospective study is the investigation of in vivo-detectable changes in metabolite concentrations during early stages of probable AlzheimerÂŽs disease (AD) using 1H-MRS. To obtain information about tissue composition the concentrations of several metabolites were estimated. The main focus of this study were the amino acids glutamate and glutamine, since an excessive supply of the neurotransmitter glutamate in the synaptic cleft is considered to be a possible cause for neurodegeneration in AD. For 29 patients with probable AD and for 19 elderly controls two volumes in parietal grey and white matter were examined at 1.5 Tesla using a single-voxel short echo PRESS sequence (TE = 22 ms, TR = 3 s). The patients had mild to moderate dementia (mini mental state examination, MMSE, 11-27). Their spectroscopic findings were compared to the data obtained from 19 healthy elderly controls. Metabolite concentrations were quantified using the software tool LCModel (Provencher 1993). For each data set the compliance with accuracy criteria was based on the %SD values. These values are calculated by the software measuring the reliability of the obtained metabolite concentrations. In patients, 25 spectra with sufficient quality were obtained from parietal grey matter (PGM) and 19 from white matter (PWM) and compared to 17 PGM spectra and 13 PWM spectra from controls. For volumes in parietal grey matter, the fraction of cerebrospinal fluid was estimated. Absolute concentrations of glutamate and glutamine (Glx), N-acetyl aspartate and N-acetyl aspartyl glutamate (tNAA), myo-Inositol (mI), creatine and phosphocreatine (tCr) and choline-containing compounds (tCh) were calculated based on the phantom replacement method. Due to overlapping proton resonances, glutamine and glutamate cannot be separated in vivo and therefore are summed up as âGlxâ. In patients, mean Glx concentration in PGM was 15,48 ± 5,15 mmol/l, in healthy controls 13,98 ± 3,14 mmol/l. The 11% increase in patients did not reach significance. In PWM, Glx concentration in probable AD patients was 8,16 ± 3,79 mmol/l, in controls 8,14 ± 3,71 mmol/l. These values had high %SD values compared to the singulett signals (tNAA, mI, tCho, tCr) since glutamate and glutamine are broadened due to the complex multiplett structures. The respective low amplitudes are sometimes difficult to discriminate from baseline modulations caused by imperfect water suppression or macromolecules, resulting in a reduced accuracy of the LCModel fit. The estimates of tNAA, mI, tCr and tCh had low %SD, indicating high accuracy of the calculated quantitative concentrations. There were no significant alterations of tNAA concentrations in either parietal grey or white matter, but in patients, tNAA showed a significant positive correlation with MMSE score in PGM. Since tNAA is considered to be a neuronal marker, this correlation may indicate a reduction in neuronal volume as the disease proceeds. Myo-inositol concentrations in patients were 20% elevated for PWM in probable AD patients compared to controls, but the difference did not reach significance (p = 0,09). In PGM, patients showed a 7% increase in mI, which was not significant either. The moderate increase in myo-Inositol in PWM for patients can be interpreted as mild gliosis, e.g. due to inflammation. There were no significant between-group differences in tCr concentrations in either of the volumina, but in patients, tCr correlated positively with MMSE score in PGM. tCh concentrations were similar in both regions in patients and controls. For probable AD patients, the fraction of cerebrospinal fluid in the parietal cortical volume was significantly increased by 16% compared to controls. This increase is in accordance with cortical atrophy in early and advanced stages of probable AD. NAA, mI, tCr and tCh concentrations were estimated with high accuracy, whereas the quantification of glutamate and glutamine at 1.5 T was difficult, mainly for technical reasons. Thus, the presented data do not provide sound information regarding potential changes of Glx concentrations in probable AD. Further improvement of in vivo Glx examination should be achieved by an improvement of signal-to-noise ratio at higher magnetic fields, e.g. 3 T MR scanners, and the use of parallel imaging
Limb-shaking transient ischemic attacks: case report and review of literature
BACKGROUND: Limb shaking Transient Ischemic Attack is a rare manifestation of carotid-occlusive disease. The symptoms usually point towards a seizure like activity and misdiagnosed as focal seizures. On careful history the rhythmic seizure like activity reveals no Jacksonian march mainly precipitated by maneuvers which lead to carotid compression. We here present a case of an elderly gentleman who was initially worked up as suffering from epileptic discharge and then later on found to have carotid occlusion. CASE PRESENTATION: Elderly gentleman presented with symptoms of rhythmic jerky movements of the left arm and both the lower limbs. Clinical suspicion of focal epilepsy was made and EEG, MRI-Brain with MRA were done. EEG and MRI-Brain revealed normal findings but the MRA revealed complete occlusion of right internal carotid artery. On a follow-up visit jerky movements of the left arm were precipitated by hyperextension and a tremor of 3â4 Hz was revealed. Based on this the diagnosis of low flow TIA was made the patient was treated conservatively with adjustment of his anti-hypertensive and anti-platelet medications. CONCLUSION: Diagnosis of limb-shaking TIA is important and should be differentiated from other disorders presenting as tremors. Timely diagnosis is important as these patients are shown to benefit from reperfusion procedures either surgical or radiological reducing their risk of stroke
Observation of the embolus protection filter for carotid artery stenting
Background: Carotid artery stenting (CAS) in high-surgical-risk patients is considered as an effective alternative to carotid endarterectomy. Since the occurrence of distal embolization with CAS is still major concern, embolus protection device is usually employed during the procedure. We developed a technique for observation of embolus protection filter and evaluate the debris or thrombus microscopically, and the pathological findings were compared with preoperative imaging studies.Patients and Methods: After completing CAS, filter membrane was stained with hematoxylin & eosin (HE) solution and removed from filer strut. Mounting onto a glass slide, filter was evaluated under microscope. Plaque debris and appearance of filter membrane were evaluated and the covered area was measured. The pathological findings were compared with preoperative imaging studies.Results: Microscopical observation of the slide revealed atheromatous debris as well as thrombotic material to the filter membrane. HE stain facilitates the characterization of the debris composition, namely thrombotic debris, calicified debris, organized debris, fibrous debris, lipid-rich debris. The subtypes of debris were consistent with preoperative imaging studies. Thus. in cases of intraprocedural flow impairment, more than 50% of filter area was covered with debris or thrombotic material.Conclusion: Carotid plaque debris captured during carotid stenting with protection filter can be visualized with HE stain on the glass side. This simple method allows us to better understand plaque debris and appearance of embolus protection filter
Cerebral Ischemia Detected with Diffusion-Weighted MR Imaging after Protected Carotid Artery Stenting: Comparison of Distal Balloon and Filter Device
Long-term prognosis of symptomatic isolated middle cerebral artery disease in Korean stroke patients
<p>Abstract</p> <p>Background</p> <p>This study aimed to investigate the long-term mortality and recurrence rate of stroke in first-time stroke patients with symptomatic isolated middle cerebral artery disease (MCAD) under medical management.</p> <p>Methods</p> <p>We identified 141 first ever stroke patients (mean age, 64.4 ± 12.5 years; 53% male) with symptomatic isolated MCAD. MCAD was defined as significant stenosis of more than 50% or occlusion of the MCA as revealed by MR angiography. The median follow-up was 27.7 months. We determined a cumulative rate of stroke recurrence and mortality by Kaplan-Meier survival analyses and sought predictors using the Cox proportional hazard model.</p> <p>Results</p> <p>The cumulative composite outcome rate (stroke recurrence or any-cause death) was 14%, 19%, 22%, and 28% at years 1, 2, 3, and 5, respectively. The annual recurrence rate of stroke was 4.1%. The presence of diabetes mellitus was the only significant independent predictor of stroke recurrence or any cause of death in multivariate analyses of Cox proportional hazard model adjusted for any plausible potential confounding factors.</p> <p>Conclusions</p> <p>We estimated the long-term prognosis of stroke patients with isolated symptomatic MCAD under current medical management in Korea. Diabetes mellitus was found to be a significant predictor for stroke recurrence and mortality.</p
Glucose modifies the effect of endovascular thrombectomy in patients with acute stroke: a pooled-data meta-analysis
Background and Purpose:
Hyperglycemia is a negative prognostic factor following acute ischemic stroke but is not known whether glucose is associated with the effects of endovascular thrombectomy in patients with large vessel stroke. In a pooled-data meta-analysis, we analyzed whether serum glucose is a treatment modifier of the efficacy of endovascular thrombectomy in acute stroke.
Methods:
Seven randomized trials compared endovascular thrombectomy with standard care between 2010 and 2017 (HERMES Collaboration). 1764 patients with large vessel stroke were allocated to endovascular thrombectomy (n=871) or standard care (n=893). Measurements included blood glucose on admission and functional outcome [modified Rankin Scale (mRS) range: 0-6; lower scores indicating less disability] at 3 months. The primary analysis evaluated whether glucose modified the effect of EVT over standard care on functional outcome, using ordinal logistic regression to test the interaction between treatment and glucose level.
Results:
Median (IQR) serum glucose on admission was 120 (104-140) mg/dl [6.6mmol/l (5.7-7.7) mmol/l]. Endovascular thrombectomy (EVT) was better than standard care in the overall pooled-data analysis [common odds ratio (acOR), 2.00 (95% CI 1.69â2.38); however, lower glucose levels were associated with greater effects of EVT over standard care. The interaction was nonlinear such that significant interactions were found in subgroups of patients split at glucose < or > 90mg/dl (5.0mmol/l) [(p=0.019 for interaction, acOR 3.81 (95% CI 1.73â8.41) for patients < 90 mg/dl vs 1.83 (95% CI 1.53â2.19) for patients > 90 mg/dl], and glucose < or > 100mg/dl (5.5mmol/l) [(p=0.004 for interaction, acOR 3.17 (95% CI 2.04â4.93) vs acOR 1.72 (95% CI 1.42â2.08)], but not between subgroups above these levels of glucose.
Conclusions:
Endovascular thrombectomy improved stroke outcomes compared to standard treatment regardless of glucose levels but the treatment effects were larger at lower glucose levels, with significant interaction effects persisting up to 90 to 100mg/dl (5.0-5.5mmol/l). Whether tight control of glucose improves the efficacy of endovascular thrombectomy following large vessel stroke warrants appropriate testing
Imaging features and safety and efficacy of endovascular stroke treatment: a meta-analysis of individual patient-level data
Background:
Evidence regarding whether imaging can be used effectively to select patients for endovascular thrombectomy (EVT) is scarce. We aimed to investigate the association between baseline imaging features and safety and efficacy of EVT in acute ischaemic stroke caused by anterior large-vessel occlusion.
Methods:
In this meta-analysis of individual patient-level data, the HERMES collaboration identified in PubMed seven randomised trials in endovascular stroke that compared EVT with standard medical therapy, published between Jan 1, 2010, and Oct 31, 2017. Only trials that required vessel imaging to identify patients with proximal anterior circulation ischaemic stroke and that used predominantly stent retrievers or second-generation neurothrombectomy devices in the EVT group were included. Risk of bias was assessed with the Cochrane handbook methodology. Central investigators, masked to clinical information other than stroke side, categorised baseline imaging features of ischaemic change with the Alberta Stroke Program Early CT Score (ASPECTS) or according to involvement of more than 33% of middle cerebral artery territory, and by thrombus volume, hyperdensity, and collateral status. The primary endpoint was neurological functional disability scored on the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included symptomatic intracranial haemorrhage, parenchymal haematoma type 2 within 5 days of randomisation, and mortality within 90 days. For the primary analysis, we used mixed-methods ordinal logistic regression adjusted for age, sex, National Institutes of Health Stroke Scale score at admission, intravenous alteplase, and time from onset to randomisation, and we used interaction terms to test whether imaging categorisation at baseline modifies the association between treatment and outcome. This meta-analysis was prospectively designed by the HERMES executive committee but has not been registered.
Findings:
Among 1764 pooled patients, 871 were allocated to the EVT group and 893 to the control group. Risk of bias was low except in the THRACE study, which used unblinded assessment of outcomes 90 days after randomisation and MRI predominantly as the primary baseline imaging tool. The overall treatment effect favoured EVT (adjusted common odds ratio [cOR] for a shift towards better outcome on the mRS 2·00, 95% CI 1·69â2·38; p<0·0001). EVT achieved better outcomes at 90 days than standard medical therapy alone across a broad range of baseline imaging categories. Mortality at 90 days (14·7% vs 17·3%, p=0·15), symptomatic intracranial haemorrhage (3·8% vs 3·5%, p=0·90), and parenchymal haematoma type 2 (5·6% vs 4·8%, p=0·52) did not differ between the EVT and control groups. No treatment effect modification by baseline imaging features was noted for mortality at 90 days and parenchymal haematoma type 2. Among patients with ASPECTS 0â4, symptomatic intracranial haemorrhage was seen in ten (19%) of 52 patients in the EVT group versus three (5%) of 66 patients in the control group (adjusted cOR 3·94, 95% CI 0·94â16·49; pinteraction=0·025), and among patients with more than 33% involvement of middle cerebral artery territory, symptomatic intracranial haemorrhage was observed in 15 (14%) of 108 patients in the EVT group versus four (4%) of 113 patients in the control group (4·17, 1·30â13·44, pinteraction=0·012).
Interpretation:
EVT achieves better outcomes at 90 days than standard medical therapy across a broad range of baseline imaging categories, including infarcts affecting more than 33% of middle cerebral artery territory or ASPECTS less than 6, although in these patients the risk of symptomatic intracranial haemorrhage was higher in the EVT group than the control group. This analysis provides preliminary evidence for potential use of EVT in patients with large infarcts at baseline.
Funding:
Medtronic
Silicone models as basic training and research aid in endovascular neurointervention-a single-center experience and review of the literature
The rapid development and wider use of neurointerventional procedures have increased the demand for a comprehensive training program for the trainees, in order to safely and efficiently perform these procedures. Artificial vascular models are one of the dynamic ways to train the new generation of neurointerventionists to acquire the basic skills of material handling, tool manipulation through the vasculature, and development of hand-eye coordination. Herein, the authors present their experience regarding a long-established training program and review the available literature on the advantages and disadvantages of vascular silicone model training. Additionally, they present the current research applications of silicone replicas in the neurointerventional arena
Association of follow-up infarct volume with functional outcome in acute ischemic stroke: a pooled analysis of seven randomized trials.
BACKGROUND: Follow-up infarct volume (FIV) has been recommended as an early indicator of treatment efficacy in patients with acute ischemic stroke. Questions remain about the optimal imaging approach for FIV measurement. OBJECTIVE: To examine the association of FIV with 90-day modified Rankin Scale (mRS) score and investigate its dependency on acquisition time and modality. METHODS: Data of seven trials were pooled. FIV was assessed on follow-up (12âhours to 2 weeks) CT or MRI. Infarct location was defined as laterality and involvement of the Alberta Stroke Program Early CT Score regions. Relative quality and strength of multivariable regression models of the association between FIV and functional outcome were assessed. Dependency of imaging modality and acquisition time (â€48âhours vs >48âhours) was evaluated. RESULTS: Of 1665 included patients, 83% were imaged with CT. Median FIV was 41âmL (IQR 14-120). A large FIV was associated with worse functional outcome (OR=0.88(95% CI 0.87 to 0.89) per 10âmL) in adjusted analysis. A model including FIV, location, and hemorrhage type best predicted mRS score. FIV of â„133âmL was highly specific for unfavorable outcome. FIV was equally strongly associated with mRS score for assessment on CT and MRI, even though large differences in volume were present (48âmL (IQR 15-131) vs 22âmL (IQR 8-71), respectively). Associations of both early and late FIV assessments with outcome were similar in strength (Ï=0.60(95% CI 0.56 to 0.64) and Ï=0.55(95% CI 0.50 to 0.60), respectively). CONCLUSIONS: In patients with an acute ischemic stroke due to a proximal intracranial occlusion of the anterior circulation, FIV is a strong independent predictor of functional outcome and can be assessed before 48âhours, oneither CT or MRI
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