bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Magnetization Transfer MRI Study of Deep Gray Matter Involvement in Multiple Sclerosis
Authors: Sharma Jitendra , Zivadinov Robert , Jaisani Zeenat , Fabiano Andrew J. , Singh Baljinder , Horsfield Mark A. , Bakshi Rohit 
Published: October 2009

ABSTRACT Background/Purpose: Gray matter involvement in multiple sclerosis (MS) is of growing interest with respect to disease pathogenesis. Magnetization transfer imaging (MTI), an advanced MRI technique, is sensitive to disease in normal appearing white matter (NAWM) in patients with MS. Design/Methods: We tested if MTI detected subcortical (deep) gray matter abnormalities in patients with MS (n= 60) vs. age‐matched normal controls (NL, n= 20). Magnetization transfer ratio (MTR) maps were produced from axial proton density, conventional spin‐echo, 5 mm gapless slices covering the whole brain. Region‐of‐interest–derived MTR histograms for the caudate, putamen, globus pallidus, thalamus, and NAWM were obtained. Whole brain MTR was also measured. Results: Mean whole brain MTR and the peak position of the NAWM MTR histogram were lower in patients with MS than NL (P < .001) and mean whole brain MTR was lower in secondary progressive (SP, n= 10) than relapsing‐remitting (RR, n= 50, P < .001) patients. However, none of the subcortical gray matter nuclei showed MTR differences in MS vs. NL, RR vs. SP, or SP vs. NL. Conclusions: The MTI technique used in this cohort was relatively insensitive to disease in the deep gray matter nuclei despite showing sensitivity for whole brain disease in MS. It remains to be determined if other MRI techniques are more sensitive than MTI for detecting pathology in these areas.
Derivation of Power M‐Mode Transcranial Doppler Criteria for Angiographic Proven MCA Occlusion
Authors: Saqqur Maher , Hill Michael D. , Alexandrov Andrei V. , Roy Jayanta , Schebel Marcia , Krol Andrea , Garami Zsolt , Shuaib Ashfaq , Demchuk Andrew M. 
Published: October 2009

ABSTRACT Background. Stringent transcranial Doppler (TCD) criteria for diagnosing occlusion are needed for more reliable TCD performance at bedside in the acute stroke setting. Subjects and Methods. At three academic stroke centers, we performed TCD examination for patients with symptoms of cerebral ischemia who underwent digital subtraction angiography (DSA). We used a standard insonation protocol with power M‐mode Doppler (PMD) TCD (TCD 100M, Spencer Technologies Inc., Seattle, WA). We collected mean flow velocity (MFV), pulsatility indices (PI), and power M‐mode resistance signature (absent, high, or low) in symptomatic middle (MCA), anterior (ACA), posterior (PCA), and in affected (a), ipsilateral (i), and contralateral (c‐lat) cerebral arteries. Ratios of aMCA/c‐lat MCA, aMCA/iACA, and aMCA/iPCA MFV were subsequently calculated. PMD‐TCD flow findings were evaluated with a receiver‐operating characteristic (ROC) analysis for angiographically proven MCA occlusion. Results. We studied 120 patients with acute cerebral ischemia with PMD‐TCD examinations prior to or immediately after DSA. Lower aMCA velocities pointed to higher probability of occlusion (P= .055). The aMCA/iPCA MFV ratio was superior to the aMCA/iACA ratio and strongly predictive of occlusion at a threshold ratio of 0.5 (RR 2.31 CI95 2.13‐2.51). High resistance or absent M‐mode flow signatures in the proximal MCA were present in 87% of M1 and M2 MCA occlusions (probability 87%). In the presence of a low‐resistance PMD signature, obtaining the aMCA/iPCA MFV ratio <0.5 increases probability of occlusion to 87%. Normal MFV ratios and low‐resistance M‐mode signatures are highly predictive of a negative angiogram for MCA occlusion. Conclusion. In acute cerebral ischemia, reliable criteria for proximal MCA occlusion have been developed based on combination of MFV ratios and M‐mode flow resistance signatures. Validation of these criteria will require multicenter studies.
Stroke Patients With Cardiac Atrial Septal Abnormalities: Differential Infarct Patterns on DWI
Authors: Santamarina Estevo , González‐Alujas M. Teresa , Muñoz Verónica , Rovira Alex , Rubiera Marta , Ribó Marc , Álvarez‐Sabin José , Molina Carlos A. 
Published: October 2009

ABSTRACT Background. Stroke mechanism in patent foramen ovale (PFO) and/or atrioseptal aneurysm (ASA) remains unclear. We aimed to study the stroke pattern on diffusion weighted imaging (DWI), in cryptogenetic stroke according to septal abnormalities. Methods. We prospectively evaluated 314 cryptogenetic strokes. Patients were categorized according to transesophageal echocardiography (TEE) findings: PFO with ASA, PFO alone, and no abnormalities. The study group consisted of 126 patients with acute DWI lesions within the first 7 days after the stroke onset. We considered the presence of scattered lesions or a cortico‐subcortical territorial lesion as highly suggestive of an embolic pattern. Results. PFO was identified in 77 patients (61%) and no alterations in 49 patients (39%). TEE revealed ASA in 42 patients (54.5% of PFO patients). An “embolic” pattern was depicted in 84 (66.7%) and subcortical in 42 (33.3%). An “embolic” pattern was significantly (P= .01) more frequently seen in PFO with ASA patients (n= 37;44%) as compared to PFO without ASA (n= 22; 26.2%) or no abnormalities (n= 25; 29.8%) on TEE. Univariate analysis revealed that age (P= .06), hyperlipidemia (P= .04), degree of shunt on TEE (P= .002), and the presence of an ASA (P= .008) were associated with an embolic pattern. After adjusting for sex, age, and vascular risk factors, only the presence of PFO, with ASA (OR 7.27; 95% CI 1.5‐35.22 P= .014) was independently associated with an embolic pattern. Conclusion. In patients with cryptogenetic stroke, the presence of PFO with ASA, but not isolated PFO, is associated with an embolic pattern on DWI. These findings provide insights into the patho‐mechanism of stroke in patients with PFO.
Visualization of Venous Systems by Time‐of‐Flight Magnetic Resonance Angiography
Authors: Ko Sang B. , Kim Dong‐Eog , Kim Se H. , Roh Jae‐Kyu 
Published: October 2009

ABSTRACT Background and purpose: Time‐of‐flight (TOF) imaging technique depicts strong signal from fresh unsaturated magnetization that moves fast into the imaging region, and TOF magnetic resonance angiography (MRA) visualizes the arterial system using saturation pulse and band. However, TOF MRA can visualize the venous system when the flow direction is reversed. Methods and patients: We consecutively enrolled patients between June 2002 and February 2003 with an internal jugular vein (IJV) and sigmoid sinus (SS) visualized by TOF MRA. Carotid Duplex ultrasonography was performed on all patients to check IJV flow directions. Gadolinium (Gd)‐enhanced MRA and conventional digital subtraction angiography were performed in selected patients. Results: The IJVs and SSs of eight patients (left = 7, right = 1) were observed by TOF MRA. In these 8 patients, Duplex ultrasonography confirmed a reversed direction in IJVs. Four of the patients underwent Gd‐enhanced MRA, which showed proximal innominate vein steno‐occlusion. Conclusions: This is the first description of IJV and SS visualization by TOF MRA. Clinical implications are discussed.
Ischemic Stroke in the Setting of Tuberculous Meningitis
Authors: Belorgey Laura , Lalani Irfan , Zakaria Asma 
Published: October 2009

ABSTRACTThe clinical syndrome of tuberculous (TB) meningitis leading to ischemic strokes is rarely seen today in immunocompetent adults native to North America. This entity is also notoriously difficult to diagnose because the presenting symptoms are often nonspecific. The authors describe a case of a man with TB meningitis which progressed to recurrent ischemic cerebral infarcts.
Lumbar Dural Ectasia Secondary to Spinal Fusion: A Report of Two Cases
Authors: Hong Tom A. , Koenigsberg Robert A. , Brown Fraser , Dastur Cyrus K. , Kanoff Richard 
Published: October 2009

ABSTRACTTwo cases of lumbar dural ectasia secondary to spinal fusion are presented. Background history of dural ectasia is discussed; computed tomography (CT) and MR imaging characteristics of dural ectasia are shown and possible causes are discussed.
Statin Use is Independently Associated with Smaller Infarct Volume in Nonlacunar MCA Territory Stroke
Authors: Shook Steven J. , Gupta Rishi , Vora Nirav A. , Tievsky Andrew L. , Katzan Irene , Krieger Derk W. 
Published: October 2009

ABSTRACT Background. Studies have shown an association between HMG‐CoA reductase inhibitors (statins) and improved stroke outcomes, possibly secondary to neuroprotective properties. Objective. To assess whether patients taking statins prior to ischemic stroke have smaller infarcts on magnetic resonance imaging (MRI), adjusting for other relevant clinical factors. Design. We retrospectively reviewed the Cleveland Clinic Foundation (CCF) Neurology Inpatient Database from June 2002 through June 2004. Demographics, medications, stroke subtype, diffusion‐weighted imaging (DWI) infarct volume, admission NIHSS, and hours to MRI were collected. Patients with a nonlacunar middle cerebral artery (MCA) territory infarct and MRI less than 48 hours from symptom onset were included (n= 143). A multivariable linear regression model was constructed to determine independent predictors of smaller infarct volume. Results. A total of 143 patients were studied, including 38 patients taking statins at the time of their stroke. In univariate analysis, patients using statins were significantly more likely to have a history of hyperlipidemia, atrial fibrillation, and coronary artery disease and to be using coumadin, antiplatelet drugs, and angiotensin‐converting enzyme inhibitors. Patients on statins had a tendency toward smaller infarcts in univariate analysis (median 25.4 cm3 vs. 15.5 cm3, P= 0.054). In multivariable linear regression analysis statin use, patient age, and TIA within the prior 4 weeks were independently associated with smaller DWI volumes; vessel occlusion on vascular imaging, and cardioembolic stroke subtype with larger infarct size. Conclusions. Statin use prior to the onset of nonlacunar MCA infarction was associated with a smaller infarct volume independent of other factors. Further studies utilizing both clinical and radiologic outcomes will be required to confirm these findings.
Cyberknife Radiosurgery for Basal Skull Plasmacytoma
Authors: Wong Eric T. , Lu Xing‐Qi , Devulapalli Janakiram , Mahadevan Anand 
Published: October 2009

ABSTRACTThe Cyberknife delivers frameless image‐guided stereotactic radiosurgery to intracranial and extracranial tumors. We report our use of Cyberknife radiosurgery on a medullary plasmacytoma in the clivus extending into the foramen magnum. No acute toxicity was seen during or within 24 hours of treatment, and the subject had a complete and durable radiographic response on MRI 12+ months after treatment. To our knowledge, this is a first case of successful Cyberknife radiosurgery of a medullary plasmacytoma.
Delirium due to Brain Microembolism: Diagnostic Value of Diffusion‐Weighted MRI
Authors: Irimia Pablo , Martinez‐Vila Eduardo , Martinez‐Cuesta Antonio , Zulueta Javier 
Published: October 2009

ABSTRACTDelirum is a common complication in hospitalized patients and it is characterized by acute disturbances of consciousness, attention, cognition, and perception. Despite the frequency with which it is observed, ischemic stroke is generally considered as an unusual cause of delirium. A subtype of brain embolism is characterized by multiple small emboli in different vascular territories, a condition known as “brain microembolism.” Given the high contrast of acute ischemic lesions in diffusion weighted imaging (DWI) this technique is particularly helpful to detect these small infarctions. We present here a patient with pulmonary metastases who was treated with bronchial artery embolization and who subsequently developed delirium due to brain microembolism. The embolic material crossed through pulmonary arteriovenous fistulas, producing multiple areas of cerebral ischemia. The ischemic lesions could be visualized only on DWI, and they affected the periventricular region, caudate nucleus, thalamus, and cerebellum.
The Value of Diffusion‐Weighted MRI in the Diagnosis of Cerebral Fat Embolism
Authors: Eguia Pablo , Medina Antonio , Garcia‐Monco Juan Carlos , Martin Vicente , Monton Fernando I. 
Published: October 2009

ABSTRACTFat embolism syndrome complicates open fractures involving long bones, although it occasionally follows nontraumatic conditions. Incomplete forms of the syndrome (ie, cerebral fat embolism) represent a challenge to diagnosis, and brain MRI represents a valuable diagnostic tool. We describe a patient who had a fat embolism to the brain after an isolated traumatic open fracture of the tibia. MRI with T2 and diffusion‐weighted images revealed multiple, reversible brain lesions, suggesting vasogenic edema and consistent with this entity. At present, MR imaging is the most sensitive technique to evaluate cerebral fat embolism.
Validation of Intracranial Area as a Surrogate Measure of Intracranial Volume When Using Clinical MRI
Authors: Nandigam R. N. Kaveer , Chen Yu‐Wei , Gurol Mahmut E. , Rosand Jonathan , Greenberg Steven M. , Smith Eric E. 
Published: October 2009

ABSTRACT Background and Purpose: We sought to determine whether mid‐sagittal intracranial area (ICA) is a valid surrogate of intracranial volume (ICV) when using retrospective data with relatively thick (6‐7 mm) sagittal slices. Methods: Data were retrospectively analyzed from 47 subjects who had two MRI scans taken at least nine months apart. Twenty‐three subjects had manual segmentation of ICV on the T2‐weighted sequence for comparison. Results: Intraclass correlation coefficient (ICC) for intraobserver, interobserver, and intraobserver scan‐rescan comparisons were 0.96, 0.97 and 0.95. Pearson correlation coefficients between ICV and ICA, averaging the cumulative 1, 2, 3, and 4 most midline slices, were 0.89, 0.94, 0.93, and 0.95. There was a significant marginal increase in explained variance of ICV by measuring two, rather than one, slices (P= 0.001). Conclusions: These data suggest that ICA, even measured without high‐resolution imaging, is a reasonable substitute for ICV.
Involvement of Jugular Valve Insufficiency in Cerebral Venous Air Embolism
Authors: Nedelmann Max , Pittermann Patrick , Gast Klaus Kurt , Mueller‐Forell Wibke , Dieterich Marianne 
Published: October 2009

ABSTRACT Background. Cerebral venous air entrapment is a rare finding on cranial computed tomography (CT) scan. Peripheral air embolism is discussed as a potential cause. However, the mechanism of retrograde passage through internal jugular valves and veins is unclear. Case Report. The case of a patient is reported, who had air entrapment in the left cavernous sinus. Prior to CT scanning, a peripheral intravenous line had been placed. Ultrasound revealed excessive insufficiency of the left internal jugular valve. To further study the mechanism of embolism, an echo contrast agent was injected into the cubital vein. A Valsalva maneuver resulted in retrograde transition of microbubbles across the insufficient valve. Valvular function on the unaffected right side was intact. Conclusions. This case report gives insight into the mechanism of cerebral venous air embolism. This is the firstcase describing jugular valve insufficiency as the missing link between peripheral air embolism and cerebral venous air entrapment.
Non‐HIV‐Related Progressive Multifocal Leukoencephalopathy (PML): A Tertiary Cancer Center Experience
Authors: Chowdhary Sajeel , Chalmers Lisa M. , Chamberlain Marc 
Published: October 2009

ABSTRACTIn the course of 1 year at a tertiary cancer center, 3 patients (2 men; 1 woman; age 51‐75 years) were seen in neurological consultation (1.5% of all consultations). Clinical course in all patients was of a progressive neurologic disorder not consistent with either a primary or secondary malignancy. Magnetic resonance (MR) imaging was most informative with respect to diagnosis and subsequent management. Brain biopsy was performed in all patients to assist in both diagnosis and prognostication. All patients were determined to have progressive multifocal leukoencephalopathy (PML) by brain biopsy.
PET OEF Reactivity for Hemodynamic Compromise in Occlusive Vascular Disease
Authors: Nemoto Edwin M. , Yonas Howard , Pindzola Ronda R. , Kuwabara Hiroto , Sashin Donald , Chang Yuefang , Jovin Tudor 
Published: October 2009

ABSTRACT Background and Purpose. Hemodynamic compromise in symptomatic patients with occlusive vascular disease (OVD) identified by cerebrovascular reserve (CVR) and oxygen extraction fraction (OEF) is an independent predictor of high stroke risk. However, up to 60% of patients compromised by CVR have normal OEF indicating a high rate of discordance. CVR is measured with an acetazolamide challenge, and OEF reactivity (OEFR) to acetazolamide, ie, a hemodynamic challenge, may reveal hemodynamic compromise and less discordance with measurements of CVR. Methods. Nine symptomatic patients with OVD were studied by positron emission tomography before and 15 minutes after 15 mg/kg intravenous acetazolamide in the middle cerebral artery territories of each hemisphere. Results. A close correlation between hemispheric CVR and OEFR was observed. Two hemispheres from two different patients showed an increase in OEF to acetazolamide challenge despite a normal baseline OEF. The two hemispheres showing an increase in OEF in response to acetazolamide were also associated with the lowest CVR and severest white matter hyperintensities. Conclusions. These observations suggest that positive OEFR may distinguish hemispheres in hemodynamic compromise despite normal OEF and show less discordance with CVR. However, these preliminary observations require confirmation in a larger study.
The Spencer's Curve: Clinical Implications of a Classic Hemodynamic Model
Authors: Alexandrov Andrei V. 
Published: October 2009

ABSTRACTMerrill P Spencer and John M Reid applied the Hagen‐Poiseuille law, continuity principle, and cerebrovascular resistance to describe a theoretical model of the relationship between the flowvelocity, flowvolume, and decreasing size of the residual vessel lumen. The model was plotted in a graph that became widely known as the Spencer's curve. Although derived for a smooth and axis‐symmetric arterial stenosis of a short length in a segment with no bifurcations being perfused at stable arterial pressures and viscosity, this model represents a milestone in understanding cerebral hemodynamics with long‐lasting practical and research implications. This review summarizes several hemodynamic principles that determine velocity and flowvolume changes, explains how the model aids interpretation of cerebrovascular ultrasound studies, and describes its impact on clinical practice and research.
Practice Standards for Transcranial Doppler Ultrasound: Part I—Test Performance
Authors: Alexandrov Andrei V. , Sloan Michael A. , Wong Lawrence K.S. , Douville Colleen , Razumovsky Alexander Y. , Koroshetz Walter J. , Kaps Manfred , Tegeler Charles H. ,   for the American Society of Neuroimaging Practice Guidelines Committee
Published: October 2009

ABSTRACTIndications for the clinical use of transcranial Doppler (TCD) continue to expand while scanning protocols and quality of reporting vary between institutions. Based on literature analysis and extensive personal experience, an international expert panel started the development of guidelines for TCD performance, interpretation, and competence. The first part describes complete diagnostic spectral TCD examination for patients with cerebrovascular diseases. Cranial temporal bone windows are used for the detection of the middle cerebral arteries (MCA), anterior cerebral arteries (ACA), posterior cerebral arteries (PCA), C1 segment of the internal carotid arteries (ICA), and collateralization of flow via the anterior (AComA) and posterior (PComA) communicating arteries; orbital windows—for the ophthalmic artery (OA) and ICA siphon; the foraminal window—for the terminal vertebral (VA) and basilar (BA) arteries. Although there is a significant individual variability of the circle of Willis with and without disease, the complete diagnostic TCD examination should include bilateral assessment of the M2 (arbitrarily located at 30‐40 mm depth), M1 (40‐65 mm) MCA [with M1 MCA mid‐point at 50 mm (range 45‐55 mm), average length 16 mm (range 5‐24 mm), A1 ACA (60‐75 mm), C1 ICA (60‐70 mm), P1‐P2 PCA (average depth 63 mm (range 55‐75 mm), AComA (70‐80 mm), PComA (58‐65 mm), OA (40‐50 mm), ICA siphons (55‐65 mm), terminal VA (40‐75 mm), proximal (75‐80), mid (80‐90 mm), and distal (90‐110 mm) BA]. The distal ICA on the neck (40‐60 mm) can be located via submandibular windows to calculate the VMCA/VICA index, or the Lindegaard ratio for vasospasm grading after subarachnoid hemorrhage. Performance goals of diagnostic TCD are to detect and optimize arterial segment‐specific spectral waveforms, determine flow direction, measure cerebral blood flow velocities and flow pulsatility in the above‐mentioned arteries. These practice standards will assist laboratory accreditation processes by providing a standard scanning protocol with transducer positioning and orientation, depth selection and vessel identification for ultrasound devices equipped with spectral Doppler and power motion Doppler.
Spinal Cord Pilomyxoid Astrocytoma: An Unusual Tumor
Authors: Mendiratta‐Lala Mishal , Kader Ellika Shehanaz , Gutierrez Jorge A. , Patel Suresh C. , Jain Rajan 
Published: October 2009

ABSTRACT We present the imaging findings of a case of spinal pilomyxoid astrocytoma in a 29‐year‐old woman with history of neck and back pain and weakness of bilateral upper extremities. A contrast‐enhanced magnetic resonance (MR) imaging study revealed an extensive intradural extramedullary lesion occupying most of the thecal sac extending from mid cervical up to the lumbosacral region with extensive contrast enhancement. Spinal pilomyxoid astrocytoma is rare with only three reported cases in pediatric population in the literature. This report illustrates the MR findings of an unusual case of intradural extramedullary spinal pilomyxoid tumor in an adult patient.
Rhombencephalosynapsis Associated with Dandy‐Walker Malformation
Authors: Sener R. Nuri 
Published: October 2009

ABSTRACT Coexistence of rhombencephalosynapsis and Dandy‐Walker malformation has previously been documented in a fetus by autopsy. In addition, there are three cases in the imaging literature suggesting this combination. This paper reports an 8‐month‐old girl with clear MR imaging evidence of association of these two anomalies. The vermis was absent, and there was fusion of the cerebellar hemispheres, characteristic for rhombencephalosynapsis. The fourth ventricle showed cystic dilatation associated with an enlarged posterior fossa, characteristic for Dandy‐Walker malformation. These findings suggest that rhombencephalosynapsis and Dandy‐Walker malformation can coexist.
Spinal Cord Compression Secondary to Epidural Bilharzioma: Case Report
Authors: Maia Antonio C.M. , Silva Luciano R.F. , Guimarães Matheus D. , Gomes Francinaldo L. , Bichuetti Denis B. , Stávale João N. , Prandini Mirto N. 
Published: October 2009

ABSTRACT A case of an epidural granuloma due to Schistosoma mansoni compressing the spinal cord at T7‐T9 is presented. The patient, a 35‐year‐old Brazilian man, started complaining of recurrent back pain since 2003. A magnetic resonance imaging (MRI) scan showed a large epidural mass extending from T7 to T9 and causing mild spinal cord compression. Through a bilateral laminectomy the bilharzioma was subtotally removed without significant bleeding. The histopathology confirmed the diagnosis of granuloma due to S. mansoni. The patient recovered completely. Although the MRI is nonspecific, this differential diagnosis should be included in homogeneous epidural lesions without bone involvement, more than ever in endemic countries or during the evaluation of travelers to those regions.