bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuroimaging in Posterior Reversible Encephalopathy Syndrome
Authors: Lamy C. , Oppenheim C. , Méder J. F. , Mas J. L. 
Published: November 2009

ABSTRACTThe terms posterior reversible leukoencephalopathy, reversibleposterior cerebral edema syndrome, and posterior reversibleencephalopathy syndrome(PRES) all refer to a clinicoradiologic entity characterized by headaches, confusion, visual disturbances, seizures, and posterior transient changes on neuroimaging. Clinical findings are not sufficiently specific to readily establish the diagnosis; in contrast, magnetic resonance imaging pattern is often characteristic and represents an essential component of the diagnosis of PRES. Typical lesions predominate in the posterior white matter, with some involvement of the overlying cortex; are hyperintense on T2‐weighted images; and are usually hypointense or isointense on diffusion‐weighted images, with an increase of the apparent diffusion coefficient, indicating vasogenic edema. The pathogenesis is incompletely understood, although it seems to be related to the breakthrough of autoregulation and endothelial dysfunction. Since its initial description, this syndrome has been subsequently described in an increasing number of medical conditions, including hypertensive encephalopathy, eclampsia, and the use of cytotoxic and immunosuppressive drugs. The diagnosis has important therapeutic and prognostic implications because the reversibility of the clinical and radiologic abnormalities is contingent on the prompt control of blood pressure and/or discontinuing the offending drug. On the contrary, when unrecognized, conversion to irreversible cytotoxic edema may occur.
Differentiating Vascular Pathophysiological States by Objective Analysis of Flow Dynamics
Authors: Crutchfield Kevin E. , Razumovsky Alexander Y. , Tegeler Charles H. , Mozayeni B. Robert 
Published: November 2009

ABSTRACT Background and Purpose. There is an unmet need to classify cerebrovascular conditions physiologically and to assess cerebrovascular system performance. The authors hypothesized that by simultaneously considering the dynamic parameters of flow velocity, acceleration, and pulsatility index (PI) (impedance) in individual Doppler spectrum waveforms, they could develop an objective method to elucidate the pathophysiology of vascular conditions and classify cerebrovascular disorders. This method, dynamic vascular analysis (DVA), is described. Methods. First, a theoretical model was developed to determine how any vascular segment and the ensemble of intracranial vascular segments could be defined according to its dynamic physiological characteristics. Next, the DVA method was applied to 847 anonymous serial complete clinical transcranial Doppler (TCD) studies of patients without regard for their diagnosis to ascertain actual reference ranges and the normality of the distribution curves for each dimension of the 3‐parameter nomogram. The authors applied DVA to 2 clinicalcases to see if they could track the changes in vascular performance of 2 known progressive diseases. Results. The theoretical analysis identified 295,245 possible vascular states for the ensemble of vascular segments in the cerebral circulation. When applied to clinical TCD data, DVA revealed continuous, normally distributed data for the velocity, PI, and logarithm of the acceleration. Conclusions. DVA is proposed as a method for monitoring the physiological state of each cerebral artery segment individually and in ensemble. DVA evaluates the relationship among acceleration (force or pressure), velocity, and PI and provides an objective means to evaluate intracranial vascular segments using the paradigm of the well‐described pressure‐perfusion autoregulation relationship. DVA may be used to study cerebrovascular pathophysiology and to classify, evaluate, and monitor cerebrovascular disorders or systemic disorders with cerebrovascular effects.
CLOTBUST: Design of a Randomized Trial of Ultrasound‐Enhanced Thrombolysis for Acute Ischemic Stroke
Authors: Alexandrov Andrei V. , Wojner Anne W. , Grotta James C. 
Published: November 2009

ABSTRACT Background: Intravenous tissue plasminogen activator (TPA) therapy can be monitored with 2 MHz transcranial Doppler (TCD). This article describes the design of CLOTBUST (combined lysis of thrombus in brain ischemia using transcranial ultrasound and systemic TPA), the first prospective international multicenter randomized clinical trial of noninvasive externally applied ultrasound to enhance systemic thrombolysis in human stroke. Subjects: Patients with acute ischemic stroke eligible for intravenous TPA therapy within 3 hours of symptom onset who have detectable middle cerebral artery occlusion on a prebolus TCD are included in this trial. All patients receive standard 0.9 mg/kg TPA therapy. Patients are randomized (1:1) to either 2 hours of continuous monitoring with TCD or placebo monitoring. FDA‐approved portable diagnostic TCD equipment and standard headframes (Marc series, Spencer Technologies, Seattle, WA) are used. Output of TCD units is set at 100% power achievable at depths of insonation that display the worst TIBI flow grade signals. Methods and End‐Points: Acute MCA occlusion on prebolus TCD is defined as thrombolysis in brain ischemia (TIBI) flow grades 0–3. Treating physicians are blinded to randomization assignment, and certified scorers measure stroke severity using the National Institute of Health Stroke Scale (NIHSS). Safety of continuous TCD monitoring is determined by rates of symptomatic (NIHSS score increase by 4+ points) intracerebral hemorrhage within 72 hours after initial symptom onset. Potential enhancement of TPA therapy will be determined using combined primary end‐point of early complete recanalization on TCD (TIBI flow grades 4‐5), dramatic recovery (NIHSS ≤ 3 points), or decline in the NIHSS ≤ 10 pointsepeatedly measured every 30 minutes within 2 hours after TPA bolus. Other end‐points include recovery at 24 hours and 3 months. modified Rankin scores (mRS) are obtained at 90 days, and favorable outcome is determined as NIHSS or mRS scores 0–1. Conclusions: The aim of phase II CLOTBUST trial is to determine the rates of early complete recanalization and dramatic/early clinical recovery in TPA+TCD and TPA groups. The sample size is set at 126 patients since a medium effect size (.50) is anticipated for TPA+TCD group vs TPA alone to achieve combined primary end‐point.
Continuous Arterial Spin Labeled Perfusion Magnetic Resonance Imaging in Patients before and after Carotid Endarterectomy
Authors: Ances Beau M. , McGarvey Michael L. , Abrahams John M. , Maldjian Joseph A. , Alsop David C. , Zager Eric L. , Detre John A. 
Published: November 2009

ABSTRACTContinuous arterial spin labeling perfusion magnetic resonance imaging (CASL‐pMRI)uses magnetically labeled arterial blood water as a tracer to obtain quantifiable measurements of cerebral blood flow (CBF)(mL/100 g−1/min−1).CASL‐pMRI was used to assess CBF changes in major vascular distributions in patients (n = 10)prior to and 3 months after carotid endarterectomy (CEA). No significant change in the global baseline CBF before and after CEA was observed in the group as a whole (P =.81). In patients with reduced CBF prior to CEA (<50 ml/100g/min), a significant increase in global CBF following CEA was observed. An inverse relationship existed between percent change in CBF after CEA versus baseline CBF within the anterior circulation (r =−.78, P <.05) but not in the posterior distribution (r =.25, P =.63). CASL‐pMRI may provide a convenient, inexpensive, noninvasive method for identifying CEA patients at risk for hyperperfusion following carotid revascularization.
Examining the Effect of Cerebral Perfusion Abnormality Magnitude on Cognitive Performance in Recently Abstinent Chronic Cocaine Abusers
Authors: Browndyke Jeffrey N. , Tucker Karen A. , Woods Steven P. , Beauvais John , Cohen Ronald A. , Gottschalk P. C. H. , Kosten Thomas R. 
Published: November 2009

ABSTRACTBackground and Purpose. Cerebral perfusion abnormalities and neuropsychological impairment are common sequelae of chronic cocaine abuse. While perfusion abnormalities have been shown to relate to cognitive deficits in this substance abuse population, the relationship between cognitive performance and the magnitude of perfusion abnormality has yet to be fully determined. Methods. Thirty‐seven abstinent cocaine abusers and 13 normal controls were administered resting 99m‐Tc‐HMPAO single photon emission computed tomography (SPECT) scans followed by a neuropsychological assessment battery tapping executive skills, attention, memory, and motor performance. Statistical parametric mapping (SPM99) techniques were used to analyze the SPECT data to detect significant regional perfusion abnormalities in the cocaine group relative to normal controls, and resulting abnormal SPECT counts were employed for comparison with the assessment measures to examine the relationship between cocaineinduced perfusion abnormalities and cognitive performance. Results. SPECT data analysis revealed significant regional perfusion abnormalities in the cocaine abuse sample relative to controls and significant differences in neuropsychological functioning on measures of executive functioning, complex attention, memory, and manual dexterity. For chronic cocaine abusers, however, within‐group comparisons of the magnitude of abnormal perfusion and neuropsychological performance were largely nonsignificant, with the exception of complex attention and motor speed. Conclusions. Perfusion abnormalities and neuropsychological impairments readily distinguished cocaine abusers from normal controls. However, when the magnitude of cocaine‐induced perfusion abnormalities is examined in relation to cognitive performance, motor speed and complex attention appear to be the best behavioral indicants of the severity of perfusion dysfunction within this substance abuse population.
Serial Positron Emission Tomography Findings in a Patient with Hydrocephalic Dementia and Alzheimer's Disease
Authors: Jeong Yong , Chin Juhee , Tae Woo Suk , Hong Seung Bong , Kim Sang Eun , Suh Yeon‐Lim , Na Duk L. 
Published: November 2009

ABSTRACTComorbidity of normal pressure hydrocephalus (NPH) and Alzheimer's disease (AD) is not uncommon. However, few studies have reported the clinical courses of these patients in depth. A 73‐year‐old woman was confirmed to have AD by a biopsy performed during a shunt operation for NPH after a head trauma. She was followed for 4 years using serial neuropsychological tests and positron emission tomography (PET). Her clinical symptoms remained improved for 2.5 years and then declined. The 1‐year minus the presurgical PET scan highlighted the bilateral frontal area, basal ganglia, and thalamus, which may reflect brain regions associated with the improvement of hydrocephalic dementia. On the other hand, the 1‐year minus the 4‐year scan highlighted the bilateral temporoparietal area and the posterior cingulate gyrus, which may reflect brain regions associated with the aggravation of AD. This subtraction method may be useful for monitoring the clinical course in patients with NPH and AD.
Rapidly Progressive Dementia Due to Bilateral Internal Carotid Artery Occlusion with Infarction of the Total Length of the Corpus Callosum
Authors: Rabinstein Alejandro A. , Romano Jose G. , Forteza Alejandro M. , Koch Sebastian 
Published: November 2009

ABSTRACTThe authors report a patient with rapidly progressive cognitive declinedue to bilateral internal carotid artery occlusion (ICAO) resulting inmultiple pathologically proven cerebral infarctions including the entire length of the corpus callosum. The gradual evolution of the deficits wassuggestive of hemodynamic ischemia. Bilateral ICAO should be consideredin the differential diagnosis of patients with rapidly cognitive decline.Although ICAO commonly spares the splenium, complete callosalinfarction is possible in the presence of bilateral ICAO.
Acquired Cerebral Hemiatrophy: Idiopathic?
Authors: Kumar Neeraj , Lindell Edward P. , Port John D. 
Published: November 2009

ABSTRACTThe authors report the case of a young man with acquired cerebral hemiatrophy that was progressive initially but stabilized after a few months. He did not have any seizure throughout the course of his illness. No definite cause was evident despite extensive investigations. He did have a slight increase in white cell count on a cerebrospinal fluid study done during the progressive phase of his illness suggesting that an unidentified infective or inflammatory illness may have resulted in the cerebral hemiatrophy. The authors suggest that Rassmusen's encephalitis may in fact be a spectrum with the typical descriptions representing one end. The importance of multimodality imaging in evaluating patients with cerebral hemiatrophy is discussed.
Clinical Applications of Transcranial Color‐Coded Duplex Sonography
Authors: Krejza Jaroslaw , Baumgartner Ralf W. 
Published: November 2009

ABSTRACTTranscranial color‐coded duplex sonography (TCCS), in contrast to “blind” conventional transcranial Doppler sonography (TCD), enables a sonographer to outline the intracranial bony and parenchymal structures, visualize the basal cerebral arteries in color, and measure angle‐corrected blood flow velocities in a specific site of the artery in question. This makes measurements of flow velocity more valid than those obtained with conventional TCD. TCCS is becoming a reliable tool for detecting the occlusion and narrowing of major intracranial arterial trunks. TCCS can image the collateral flow through the anterior and posterior communicating arteries in patients with unilateral, high‐grade stenosis or occlusion of the extracranial internal carotid artery, without using potentially dangerous compression tests. Large and medium‐sized arteriovenous malformations can also be detected with TCCS. The rapid sonographic assessment of cerebral hemodynamics in a neurosurgical patient with increased intracranial pressure can guide further management. The use of sonographic contrast agents can increase the number of conclusive TCCS studies in patients with insufficient acoustic windows.
A Method for the Automated Assessment of Temporal Characteristics of Functional Hemispheric Lateralization by Transcranial Doppler Sonography
Authors: Deppe M. , Knecht S. , Lohmann H. , Ringelstein E. B. 
Published: November 2009

ABSTRACT Background and Purpose. Transcranial Doppler sonography (TCD) can guide and complement investigations based on functional magnetic resonance and positron emission tomography imaging by providing continuous information on cerebral perfusion changes correlated to cerebral activation. So far, however, the role of functional TCD has been limited by a lack of sensitivity.Methods. Here, the authors present an outline of a method that increases the potential of TCD to detect perfusion changes within a vascular territory. Sensitivity on the order of 1% can be achieved by transformation of Doppler envelope curves, which accounts for systemic quasi‐periodic and irregular spontaneous blood flow modulations and artificial disturbances related to the recording. A statistical technique is introduced that allows the automatic detection of time periods of significant hemispheric lateralization in evoked flow studies. Furthermore, an index of laterality is defined quantifying the extent of hemispheric dominance during stimulus processing.Results and Discussion. The analysis technique described in this article has been successfully employed in recent examinations on vision, motor activation, language, language recovery, and other cognitive tasks. Conclusion. The novel functional TCD technique permits valid and reproducible assessments of the temporal characteristics of functional hemispheric lateralization.
Improving Cerebral Cortical Magnetic Resonance Imaging Using a Readily Available Surface Coil
Authors: Gomez‐Hassan Diana M. , Blaesing Cathy , Shattock Steven , Chenevert Thomas L. 
Published: November 2009

ABSTRACTSubtle structural deformities of the cerebral cortex have been shown to be the cause of seizures in patients with refractory epilepsy. Brain imaging using high‐resolution focused protocols with standard head coils may not provide sufficient image quality needed for evaluating subtle cortical abnormalities. The authors describe the use of a readily available shoulder coil placed over a specific area of the brain that has been clinically determined to enhance the signal to noise and resolution of the cortical surface. Delineating the cortical surface using a shoulder coil can help to detect subtle areas of cortical thickening, blurring of the gray‐white matter junction, or focally abnormal gyral and sulcal patterns.
Computed Tomography Angiographic Correlates of Early Computed Tomography Signs in Acute Ischemic Stroke
Authors: Garg Neeta , Eshkar Noam , Tanenbaum Lawrence , Cohen Barry , Sen Souvik 
Published: November 2009

ABSTRACT Background and Purpose. Early computed tomography (CT) signs of stroke signify major arterial occlusion. CT angiogram (CTA) is useful in detecting major arterial occlusion and may help triaging patients for intra‐arterial thrombolysis. The correlation between the early signs of stroke and arterial occlusion on CTA was studied.Methods. Consecutive patients with suspected acute anterior circulation ischemic stroke presenting within 6 hours of symptom onset underwent noncontrast CT of the head followed by CTA. The scans were later reviewed for evidence of early signs of stroke on CT scan and intracranial arterial occlu‐sion on CTA.Results. Sixteen of 65 patients had arterial occlu‐sion on CTA; 12 (75%) of these showed the early CT signs of stroke. All the early signs except M2 “dot” sign significantly cor related with middle cerebral artery (MCA) occlusion on CTA. Hyperdense MCA sign was the only independent predictor of a MCA occlusion.Conclusion. In a small sample, early CT signs of stroke strongly correlated with arterial occlusion, with hyperdense MCA sign being the most predictive of a MCA occlusion.
Common Carotid Artery Remodeling Studied by Sonomorphological Criteria
Authors: Kazmierski Radoslaw , Watala Cezary , Lukasik Maria , Kozubski Wojciech 
Published: November 2009

ABSTRACT Background and Purpose. Only a few attempts have been made to establish the impact of critical intima‐media thickness (IMT) on narrowing of the lumen of the common carotid artery (CCA). In the present study, sonomorphological criteria have been used to assess how intima‐media thickening in the CCA may influence the artery geometry.Methods. High‐resolution ultrasonography was employed in 233 patients (466 arteries) to quantify the selected parameters of CCA biometry: IMT, arterial lumen diameter (LD), interadventitial diameter (IAD), and outer artery diameter (OAD).Results. With an increase of CCA IMT up to the critical point of 1.2 mm, the LD showed parallel compensatory increases. Above the inflection point of 1.3 mm, the lumen became progressively narrower proportionally to the increasing IMT.Conclusion. There are limits to the compensa‐tory enlargement of the CCA lumen. Above the inflection point of CCA IMT of 1.3 mm, the artery lumen becomes progressively narrower with increasing IMT.
Combined Surgical and Endovascular Management of a Complex Posttraumatic Dural Arteriovenous Fistula of the Tentorium and Straight Sinus
Authors: Zink Walter E. , Meyers Philip M. , Connolly E. Sander , Lavine Sean D. 
Published: November 2009

ABSTRACTDiagnosis and management of a complex tentorial dural arteriovenous fistula (DAVF) of the straight sinus with vein of Galen aneurysmal dilatation is presented. A 65‐year‐old woman with remote history of cranial gunshot lapsed into coma after months of progressive neurological decline. Computed tomography brain scan showed cerebellar hemorrhage while arteriography demonstrated a complex arteriovenous fistula of an isolated straight sinus and tentorium with extensive arterial supply. First extracranial then intracranial arterial feeders to the fistula were occluded in separate procedures following initial presentation. Eleven days after presentation, an occipital burr‐hole craniotomy was performed, the isolated straight sinus was cannulated under fluoroscopic guidance, and the fistula eradicated with multiple thrombogenic fibered platinum and Gugliemi detachable coils. Staged embolization now represents the standard of care for many complex DAVFs. A multi‐disciplinary surgical and endovascular approach is a valuable combination to cure deep lesions with limited surgical or transvascular access.
“Whippets”‐Induced Cobalamin Deficiency Manifesting as Cervical Myelopathy
Authors: Diamond Alan L. , Diamond René , Freedman S. Mitchell , Thomas Florian P. 
Published: November 2009

ABSTRACT Background. Nitrous oxide (N O) is inhaled in anesthesia and as a recreational drug from whipped cream dispensers. Its abuse reaches −10% in some age groups. By inactivating cobalamin (Cbl) (vitamin B12), N O can cause neurologic and hematologic manifestations. We present a case of N O‐induced Cbl deficiency presenting as cervical myelopathy. Case History. After regularly inhaling N O for many months, a 31‐year‐old man developed limb paresthesiae and ataxia over 3 months. Examination revealed finger pseudoathetosis, hyporeflexia, decreased sensation, and gait ataxia. Brain magnetic resonance imaging (MRI) was normal, but the posterior columns of the cervical and upper thoracic cord revealed patchy nonenhancing hyperintense lesions. Serum Cbl was 98 pg/mL (normal = 170–900 pg/mL). Cbl replacement led to recovery within 3 months.Discussion. This patient presented with the symptoms and signs of Cbl deficiency. The MRI lesions in the posterior columns aided the diagnosis. Physicians need to have a high level of suspicion in cases of unexplained Cbl deficiency and myelopathy.
Parasellar Solitary Fibrous Tumor of Meninges: Magnetic Resonance Imaging Features With Pathologic Correlation
Authors: Lo Chung‐Ping , Chen Cheng‐Yu , Lin Chih‐Kung , Chin Shy‐Chyi , Juan Chun‐Jung , Hsueh Chun‐Jen 
Published: November 2009

ABSTRACTSolitary fibrous tumor (SFT) is a benign mensenchymal neoplasm of spindle‐cell origin. The authors report the case of a 50‐year‐old man with SFT arising from the meninges of the left parasellar region with cavernous sinus involvement. The tumor was demonstrated isointense on T1‐weighted and heterogeneously hypointense on T2‐weighted magnetic resonance imaging (MRI) with strong contrast enhancement. The preoperative MRI diagnosis was meningioma or hemangiopericytoma. Pathological study revealed an SFT that stained positive immuno‐histochemically for CD34 and vimentin.
Neuroimaging of Hypoxia and Cocaine‐Induced Hippocampal Stroke
Authors: Bolouri Mohammad Reza , Small George A. 
Published: November 2009

ABSTRACTThe hippocampus has been a subject of numerous studies of behavior and memory in patients who demonstrate atrophy, sclerosis, or injury by autopsy or imaging. It has also been studied in patients who undergo surgical treatment for intractable epilepsy. The effects of hypoxia and ischemia on the hippocampus have been studied in animals; however, human cases of hippocampal stroke are rarely reported. The authors report a case of bilateral hippocampal stroke in a patient with severe ischemia secondary to cardiac arrest and cocaine exposure. These findings likely resulted from the combination of hypoxia and cocaine‐related excitotoxicity.