bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi‐Site Phasic Neural Activity Mediates the Execution of An Auditory Continuous Performance Task: A PET and Electrophysiological Study
Authors: Lockwood Alan H. , Wack David S. , Benedict Ralph H. B. , Coad Mary Lou , Sussman Joan E. , Burkard Robert F. 
Published: October 2009

ABSTRACTBACKGROUND AND PURPOSE We studied an auditory continuous performance task with positron emission tomography (PET) and EEG‐derived current density reconstructions (CDRs) to define the spatial and temporal aspects of auditory attention. METHODS The CDRs were employed to segregate responses to targets and non‐targets at sites identified by PET. We then studied the time course of brain activity using statistical parametric mapping (SPM) of the CDR data. RESULTS In contrast to target EEG activity, non‐targets did not produce significant peaks after 300 ms. Pre‐300 ms biphasic activation of auditory, left posterior frontal, left supplemental, and primary motor cortices and the anterior cingulate (AC) and biphasic suppression of posterior cingulate and occipital cortex were identical for targets and non‐targets and may mediate the target non‐target decision. SPM analysis of post‐300 ms CDRs showed cingulate cortices were the first to be reactivated, remained active through 672 ms, and were accompanied by reactivation and deactivation of the same sites observed in the pre‐P300 responses. CONCLUSIONS The cingulate may play an important role in post‐decisional activity and control activity at other sites involved in post‐decisional cognitive processing.
Regional Specificity of Magnetization Transfer Imaging in Multiple Sclerosis
Authors: Tjoa Christopher W. , Benedict Ralph H. B. , Dwyer Michael G. , Carone Dominic A. , Zivadinov Robert 
Published: October 2009

ABSTRACTBACKGROUND The goal of this study was to develop and validate a method for generation of regional magnetization transfer ratio (MTR). We also studied the topography of MTR changes in multiple sclerosis (MS) and in normal controls (NC), and preliminarily examined the clinical usefulness of this method. METHODS We examined 45 patients with MS (relapsing remitting [RR]= 28 and secondary progressive [SP]= 17] and 19 NC. Mean disease duration was 14.3 years and median Expanded Disability Status Scale was 3.0. Regions of the brain were determined using semiautomated brain region extraction (SABRE). Twenty‐six regional masks were automatically applied to MTR maps that were further split into gray matter (GM) and white matter (WM) compartments. RESULTS Mean MTR from 12 SABRE regions differed significantly between MS patients and NC. For WM, all regional mean MTRs differed significantly between RR, SP, and NC participants (P < .001). In regression analysis, only 3 regions remained significantly different when corrected for total T2‐LV. The regression model predicting disability selected GM mean MTR of the right medial inferior frontal region (P= .031). CONCLUSIONS The study results showed that this regional MTR approach is reproducible, reliable and clinically relevant. MTI changes occur selectively in specific sub‐regions.
Proton Magnetic Resonance Spectroscopy Detects a Relative Decrease of N‐Acetylaspartate in the Hippocampus of Patients With Dementia With Lewy Bodies
Authors: Xuan Xiaqing , Ding Meiping , Gong Xiangyang 
Published: October 2009

ABSTRACTBACKGROUND AND PURPOSE To characterize the cerebral metabolic changes in dementia with Lewy bodies patients. METHODS The metabolic ratios of NAA/Cr and Cho/Cr in bilateral hippocampus were determined by proton magnetic resonance spectroscopy in 8 patients and 8 age‐matched healthy controls. RESULTS Dementia with Lewy bodies patients showed significantly lower NAA/Cr ratios in bilateral hippocampus, while the Cho/Cr ratio did not differ from the control group. CONCLUSIONS Our data show relatively decrease of N‐acetylaspartate in the hippocampus of patients with early or intermediate stage DLB. Hence, damage of neurons seems to be an early alteration in DLB.
Lactate Detection by MRS in Mitochondrial Encephalopathy: Optimization of Technical Parameters
Authors: José da Rocha Antônio , Túlio Braga Flávio , Carlos Martins Maia Júnior Antonio , Jorge da Silva Carlos , Toyama Carlos , Pereira Pinto Gama Hugo , Kok Fernando , Rodrigues Gomes Hélio 
Published: October 2009

ABSTRACT Mitochondriopathies are a heterogeneous group of diseases with variable phenotypic presentation, which can range from subclinical to lethal forms. They are related either to DNA mutations or nuclear‐encoded mitochondrial genes that affect the integrity and function of these organelles, compromising adenosine triphosphate (ATP) synthesis. Magnetic resonance (MR) is the most important imaging technique to detect structural and metabolic brain abnormalities in mitochondriopathies, although in some cases these studies may present normal results, or the identified brain abnormalities may be nonspecific. Magnetic resonance spectroscopy (MRS) enables the detection of high cerebral lactate levels, even when the brain has normal appearance by conventional MR scans. MRS is a useful tool for the diagnosis of mitochondriopathies, but must be correlated with clinical, neurophysiological, biochemical, histological, and molecular data to corroborate the diagnosis. Our aim is to clarify the most relevant issues related to the use of MRS in order to optimize its technical parameters, improving its use in the diagnosis of mitochondriopathies, which is often a challenge.
Long‐Term Study of Brain 1H‐MRS Study in Multiple Sclerosis: Effect of Glatiramer Acetate Therapy on Axonal Metabolic Function and Feasibility of Long‐Term 1H‐MRS Monitoring in Multiple Sclerosis
Authors: Khan Omar , Shen Yimin , Bao Fen , Caon Christina , Tselis Alexandros , Latif Zahid , Zak Imad 
Published: October 2009

ABSTRACT Glatiramer acetate (GA) has several putative mechanisms of action with the potential of limiting sublethal axonal injury in the central nervous system (CNS). Brain proton magnetic resonance spectroscopy (1H‐MRS) allows in vivo examination of axonal integrity by quantifying the neuronal marker N‐acetylaspartate (NAA), often expressed as a ratio to creatine (Cr). We showed that treatment with GA led to improvement in NAA/Cr over a 2‐year period. We now report the results of this ongoing study after 4 years of annual brain 1H‐MRS examinations. Compared to baseline, at year 4, patients receiving continuous GA therapy showed a 12.7% increase in NAA/Cr and (P= .03) in the multivoxel brain volume of interest (VOI) studied and by 9.6% (P= .04) in the normal‐appearing white matter within the VOI. Three patients in the control group who began therapy with GA during the course of the study showed similar increases in NAA/Cr after the first year of therapy. These data support the long‐term effect of GA on maintaining axonal metabolic function and protection from sublethal injury as well as the feasibility of employing brain 1H‐MRS in long‐term investigative studies in MS.
Magnetic Resonance Spectroscopic Imaging Detects Abnormalities in Normal‐Appearing Frontal Lobe of Patients With Sturge‐Weber Syndrome
Authors: Batista Carlos E. A. , Chugani Harry T. , Hu Jiani , Haacke E. Mark , Behen Michael E. , Helder Emily J. , Juhász Csaba 
Published: October 2009

ABSTRACTBACKGROUND In Sturge‐Weber syndrome (SWS), structural MRI abnormalities are most common in the posterior brain regions. Frontal lobe involvement increases the risk of motor impairment. The goal of this study was to determine whether Magnetic Resonance Spectroscopic Imaging (MRSI) can improve detection of frontal lobe involvement in children with SWS. METHODS Sixteen children (age: .9‐10.4 years) with unilateral SWS underwent MRI with MRSI prospectively. N‐acetyl‐aspartate (NAA) and choline asymmetries in the posterior and frontal regions were measured. RESULTS Eight children presented normal‐appearing frontal lobes on conventional MRI, but 7 of them showed abnormal NAA and/or choline content in the frontal lobe of the affected hemisphere. Lower frontal lobe gray matter NAA was associated with earlier onset of seizures (r= .76; P= .04) and impaired motor function (r=−.89, P < .001). Frontal NAA asymmetry was an independent predictor of motor function in a regression analysis (P= .01) CONCLUSION MRSI is more sensitive than conventional structural MRI for detection of frontal lobe involvement in SWS. Decreased frontal lobe NAA is an excellent predictor of motor functions. Thus, MRSI can provide complementary information for the assessment of normal‐appearing brain regions, and may assist prognosis evaluation in children with SWS.
Angiographic Demarcation of an Occlusive Lesion May Predict Recanalization after Intra‐arterial Thrombolysis in Patients with Acute Middle Cerebral Artery Occlusion
Authors: Otsuka Yoshinobu , Waki Riichiro , Yamauchi Hiroshi , Fukazawa Seiji , Kimura Kaku , Shimizu Kotoyuki , Fukuyama Hidenao 
Published: October 2009

ABSTRACTBACKGROUND AND PURPOSE The aim of this study is to investigate whether angiographic demarcation of an occlusive lesion may predict successful or failed result of intra‐arterial thrombolysis in acute middle cerebral artery (MCA) occlusion. METHODS We reviewed retrospectively the angiography and clinical data of acute MCA occlusion patients who underwent intra‐arterial thrombolysis from 1994 to 2004. Pretreatment angiographic findings at the occlusive lesions were classified as either blurred or sharp, depending on whether the proximal portion of the occlusive lesions had poorly or well demarcated margins. Using uni‐ or multivariate analysis, recanalization was correlated with our angiographic classification or other clinical variables. RESULTS Forty‐six patients with MCA occlusions underwent intra‐arterial thrombolysis during the 10‐year period. Forty‐four of the angiograms could be classified into one of the two categories: Blurred‐type in 20 patients and Sharp‐type in 24 patients. Univariate analysis showed a significant association of the classification with recanalization. (Recanalization rate: 95% in Blurred‐type and 38% in Sharp‐type, P < .0001) Logistic regression analysis showed that the association was independent from other factors (P= .004). CONCLUSION In acute MCA occlusion, our classification may indicate the difficulty of the recanalization procedure, and may assist in patient triage for different intra‐arterial treatment strategies.
Qualification Requirements for Performing Neurointerventional Procedures: A Report of the Practice Guidelines Committee of the American Society of Neuroimaging and the Society of Vascular and Interventional Neurology
Authors: Qureshi Adnan I. , Abou‐Chebl Alex , Jovin Tudor G. 
Published: October 2009

ABSTRACTThe aim of this document is to summarize the existing data derived from regulatory bodies, professional organizations, and clinical trials with direct pertinence to indications and qualifications required for performing neurointerventional procedures and provide recommendations regarding qualifications required for performing individual neurointerventional procedures. Recommendations are provided for performance of cerebral angiography, intra‐arterial thrombolysis, carotid angioplasty and stent placement, intracranial angioplasty and stent placement, and endovascular treatment of intracranial aneurysms and arteriovenous malformations.
Embolic Doppler Ultrasound Signal Detection Using Continuous Wavelet Transform to Detect Multiple Vascular Emboli
Authors: Ng Him Shing , Hao Qing , Leung Thomas , Lawrence Wong K. S. , Nygaard Hans , Hasenkam J. Michael , Johansen Peter 
Published: October 2009

ABSTRACTBACKGROUND Ischemic stroke is mainly caused by embolism. Vascular emboli can be solid or gaseous and can be non‐invasively registered by transcranial Doppler ultrasound as microembolic signals (MESs). The existing methods are limited as they do not distinguish between cases in which a single embolus is present and those in which multiple emboli—perhaps a mix of those gaseous and solid in nature—are present. In a previous in vitro study, we have developed a wavelet‐based algorithm to detect multiple emboli. We proceed with this technique to investigate whether it could prove useful in patients. METHOD MESs were collected during emboli monitoring from patients undergoing carotid artery stenting and from patients having middle cerebral artery stenosis, and continuous wavelet transform was used to detect multiple emboli. RESULTS From 17 MESs recorded from middle cerebral artery stenosis patients, we found no multiple MES. From 306 MESs recorded from carotid stenting, we found 31 multiple MESs. CONCLUSION Multiple emboli were detected and quantified in patients using continuous wavelet transform. These were difficult to observe using conventional analysis techniques.
Hypertensive Encephalopathy Presenting with Isolated Brain Stem and Cerebellar Edema
Authors: Bhagavati Satyakam , Chum Florence , Choi Jai 
Published: October 2009

ABSTRACTHypertensive encephalopathy typically presents with headache and confusion and bilateral parietooccipital vasogenic edema. Brain stem and cerebellar edema in hypertensive encephalopathy usually occurs in association with these typical supratentorial changes and is usually asymptomatic. We report here an uncommon hypertensive patient with isolated, severe, and symptomatic brain stem and cerebellar edema with fourth ventricular obstruction and mild hydrocephalus. Rapid treatment of hypertension resulted in clinical and radiological improvement. Prompt recognition of the cause and aggressive treatment of hypertension in such patients are crucial to relieve edema and prevent life‐threatening progression.
CT Angiography is Cost‐Effective for Confirmation of Internal Carotid Artery Occlusions
Authors: Brown Devin L. , Hoffman Stuart N. , Jacobs Teresa L. , Gruis Kirsten L. , Johnson Susan L. , Chernew Michael E. 
Published: October 2009

ABSTRACTBACKGROUND AND PURPOSE While sensitive to internal carotid artery (ICA) occlusion, carotid ultrasound can produce false‐positive results. CT angiography (CTA) has a high specificity for ICA occlusion and is safer and cheaper than catheter angiography, although less accurate. We determined the cost‐effectiveness of CTA versus catheter angiography for confirming an ICA occlusion first suggested by carotid ultrasound. METHODS A Markov decision‐analytic model was constructed to estimate the cost‐effectiveness of CTA compared with catheter angiography in a hypothetical cohort of symptomatic patients with a screening examination consistent with an ICA occlusion. Costs in 2004 dollars were estimated from Medicare reimbursement. Effectiveness was measured in quality‐adjusted life years. RESULTS The 2‐year cost in the CTA scenario was $9,178, and for catheter angiography, $11,531, consistent with a $2,353 cost‐savings per person for CTA. CTA resulted in accrual of 1.83 quality‐adjusted life years while catheter angiography resulted in 1.82 quality‐adjusted life years. CTA was less costly and marginally more effective than catheter angiography. In sensitivity analyses, when CTA sensitivity and specificity were allowed to vary across a plausible range, CTA remained cost‐effective. CONCLUSIONS After screening examination has suggested an ICA occlusion, confirmatory testing with CTA provides similar effectiveness to catheter angiography and is less costly.
Detection of Right‐to‐Left Shunts: Comparison between the International Consensus and Spencer Logarithmic Scale Criteria
Authors: Lao Annabelle Y. , Sharma Vijay K. , Tsivgoulis Georgios , Frey James L. , Malkoff Marc D. , Navarro Jose C. , Alexandrov Andrei V. 
Published: October 2009

ABSTRACTBACKGROUND International Consensus Criteria (ICC) consider right‐to‐left shunt (RLS) present when Transcranial Doppler (TCD) detects even one microbubble (μB). Spencer Logarithmic Scale (SLS) offers more grades of RLS with detection of >30 μB corresponding to a large shunt. We compared the yield of ICC and SLS in detection and quantification of a large RLS. SUBJECTS AND METHODS We prospectively evaluated paradoxical embolism in consecutive patients with ischemic strokes or transient ischemic attack (TIA) using injections of 9 cc saline agitated with 1 cc of air. Results were classified according to ICC [negative (no μB), grade I (1‐20 μB), grade II (>20 μB or “shower” appearance of μB), and grade III (“curtain” appearance of μB)] and SLS criteria [negative (no μB), grade I (1‐10 μB), grade II (11‐30 μB), grade III (31100 μB), grade IV (101300 μB), grade V (>300 μB)]. The RLS size was defined as large (>4 mm) using diameter measurement of the septal defects on transesophageal echocardiography (TEE). RESULTS TCD comparison to TEE showed 24 true positive, 48 true negative, 4 false positive, and 2 false negative cases (sensitivity 92.3%, specificity 92.3%, positive predictive value (PPV) 85.7%, negative predictive value (NPV) 96%, and accuracy 92.3%) for any RLS presence. Both ICC and SLS were 100% sensitive for detection of large RLS. ICC and SLS criteria yielded a false positive rate of 24.4% and 7.7%, respectively when compared to TEE. CONCLUSIONS Although both grading scales provide agreement as to any shunt presence, using the Spencer Scale grade III or higher can decrease by one‐half the number of false positive TCD diagnoses to predict large RLS on TEE.
Novel Applications of Magnetic Resonance Imaging to Image Tissue Inflammation after Stroke
Authors: Nighoghossian Norbert , Wiart Marlene , Berthezene Yves 
Published: October 2009

ABSTRACTExperimental studies suggest that stroke‐induced brain damage progresses during subacute stages. Cerebral ischemic injury is associated with the induction of a series of inflammatory events, including the infiltration of circulating immune cells and activation of resident cells. Local brain inflammation is spatiotemporally related to the occurrence of delayed apoptotic cell death. Therefore, ischemia‐associated inflammation may not only play a major role in the pathogenesis of neurodegeneration associated with stroke, but may also mediate beneficial effects such as lesion demarcation, wound healing, and tissue regeneration especially via secretion of nerve growth factors. In this context, noninvasive imaging of inflammation associated with ischemic stroke lesions could have a predictive value and may be helpful for the development of cytoprotective drugs.
Intravascular Ultrasound to Assess Extracranial Vertebral Artery Restenosis: Case Report
Authors: Gupta Rishi , Bhatt Archit , Kassab Mounzer , Majid Arshad 
Published: October 2009

ABSTRACTWe present a case report of a patient who developed restenosis 5 months after initial stent placement. computed tomography (CT) angiography revealed a 70% stenosis, while conventional angiography revealed a 40% stenosis. An intravascular ultrasound (IVUS) was used to assess the degree of narrowing along with the mechanism causing the stenosis. IVUS can be utilized to resolve discrepancies between imaging modalities for degree of stenosis and also aid in determining the mechanism of restenosis after stent placement in the extracranial vertebral arteries.
Leo Stent‐Assisted Coil Embolization of a Giant Middle Cerebral Artery Aneurysm
Authors: Ahn Jung Yong , Hong Chang Ki , Suh Sang Hyun , Cho Jun Hyung , Shim Yo Shik , Huh Ji Soon 
Published: October 2009

ABSTRACTWe report a case of a 70‐year‐old man harboring a wide‐necked thrombosed giant aneurysm of the left middle cerebral artery (MCA) on the M1 segment. The patient presented with generalized tonic‐clonic seizures. A computerized tomography scan showed a calcified aneurysmal wall with perianeurysmal swelling. The aneurysm was successfully embolized using closed‐cell nitinol stent‐assisted coiling (Leo, BALT Co., Montmorency, France).
Normalized Upper Cervical Spinal Cord Atrophy in Multiple Sclerosis
Authors: Song Feng , Huan Yi , Yin Hong , Ge Yali , Wei Guangquan , Chang Yingjuan , Zhao Haitao 
Published: October 2009

ABSTRACTBACKGROUND AND PURPOSETo find an optimal normalizing factor for upper cervical spinal cord area (UCCA) and to establish whether, in a cross‐sectional study, the normalized UCCA correlates better with the neurological disability than the absolute measurement in multiple sclerosis patients.METHODSUCCA and three potential normalizing factors were estimated from magnetic resonance imaging data in 51 control subjects. Their reliability was assessed and the linear relationships between UCCA and three potential correction factors were investigated. UCCA was then normalized by these factors respectively. On the basis of these results, an optimal factor was selected and applied to 29 MS subjects.RESULTSAn extremely strong correlation between UCCA and LECA was seen (r= .88, P < .01). The coefficient of variation (COV) of UCCA was reduced to 4.4% from 9.3% after correction by LECA. The normalized measurement of UCCA correlated better with the expanded disability status scale (EDSS) than the absolute measurement especially in relapsing‐remitting multiple sclerosis patients. Moreover, more spinal cord atrophy was identified in corrected data than uncorrected data.CONCLUSIONOur findings suggest that LECA is an optimal correction factor for UCCA and normalized UCCA is preferable to absolute measurement in cross‐sectional study.
Reversible Hyperintense Lesion after Balloon Occlusion Test
Authors: Haraguchi Koichi , Houkin Kiyohiro , Koyanagi Izumi , Nonaka Tadashi , Baba Takeo 
Published: October 2009

ABSTRACT We report a unique case of a reversible high signal intensity lesion observed on a magnetic resonance (MR) image accompanied by transient neurological deficits related to a balloon occlusion test. This abnormality was considered to be vasogenic edema caused by the disruption of the blood‐brain barrier (BBB) due to a long history of uncontrolled hypertension and transient ischemia induced by the balloon occlusion test.
CT Imaging Features of Carotidynia: A Case Report
Authors: Park Ji Kang , Choi Jay Cheol , Kim Bong Soo , Choi Gukmyung , Kim Seung Hyung 
Published: October 2009

ABSTRACT Despite denial as a disease entity, carotidynia had shown relatively concordant imaging finding as an inflammatory process surrounding the carotid bifurcation area. We report serial computed tomography (CT) images of a case with carotidynia that showed the layered thickening of the carotid wall with self‐limiting disease course.
Qureshi Grading Scheme Predicts Subsequent Volume of Brain Infarction Following Intra‐Arterial Thrombolysis in Patients with Acute Anterior Circulation Ischemic Stroke
Authors: Mohammad Yousef M. , Christoforidis Greg A. , Bourekas Eric C. , Slivka Andrew P. 
Published: October 2009

ABSTRACTBACKGROUND The importance of the site of occlusion and the presence or absence of collaterals on initial angiography in patients with acute ischemic stroke has been recognized. Qureshi recently proposed a scheme that categorizes patients with ischemic stroke based on findings observed on initial angiography. METHODS We determined the relationship between severity of angiographic occlusion using Qureshi grading scheme and volume of brain infarction on follow‐up computed tomography in 55 patients with anterior circulation ischemic stroke who underwent intra‐arterial thrombolysis. RESULTS A strong association was observed between Qureshi grades and volume of brain infarction (F ratio 6.2, P= .0005) after adjusting for patients' age, sex, National Institutes of Health Stroke Scale (NIHSS) score, thrombolytic used, and time interval between symptom onset and angiography. The relationship persisted after further adjustment for final angiographic recanalization (F ratio 5.1, P= .001). A significant relationship between initial grades and volume of brain infarction was separately observed in both patients with or without recanalization following treatment. CONCLUSIONS Qureshi grading scheme can be effectively used to stratify patients with anterior circulation ischemic stroke undergoing intra‐arterial thrombolysis using initial angiographic findings.