bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sources of Variability in the Detection of Cerebral Emboli with Transcranial Doppler During Cardiac Surgery
Authors: Rodriguez Rosendo A. , Rubens Fraser , Rodriguez Carlos D. , Nathan Howard J. 
Published: October 2009

ABSTRACT Objective. The application of intensity thresholds for embolus detection with transcranial Doppler (TCD) can exclude from analysis an unrecognized proportion of high‐intensity transient signals (HITS))whose intensities are below the threshold. The lack of consistent threshold criteria between clinical trials may explain part of the discrepancy in the reported HITS counts. We investigated the effect of choosing different thresholds on the sensitivity and specificity of detecting HITS during cardiopulmonary bypass (CPB). Methods. Two observers independently analyzed TCD recordings from 8 patients under CPB. Doppler signals were classified as true HITS, equivocal HITS, artifacts, and Doppler speckles according to preestablished criteria. The relative intensity of Doppler signals was measured by two different methods (TCD software vs manual). Receiver Operating Characteristic curves determined the optimal threshold for each of the two intensity methods. Results. Reviewers achieved agreement in 96% of 2190 Doppler signals (κ= 0.90). Relative intensities calculated with the TCD‐software method were 3 dB (95% CI: 3.0‐3.4) higher than the manual method. The optimal threshold was found at 10 dB (sensitivity: 99%; specificity: 90.8%) with the software method and at 7 dB with the manual method (sensitivity: 96%; specificity: 83%). The use of an intensity threshold 2 dB higher than the optimal increased the rejection of true HITS by 8% and 14%, respectively. Conclusions. Using intensity thresholds higher than the optimal for embolus detection decreases HITS counts. Choosing a threshold depends on the type of method used for measuring the signal intensity. Uniform threshold criteria and comparative studies between different Doppler devices are necessary for making clinical trials more comparable.
Measurement of Cortical Thickness in 3D Brain MRI Data: Validation of the Laplacian Method
Authors: Haidar Haissam , Soul Janet S. 
Published: October 2009

ABSTRACT Objectives. We aimed to determine the precision of the Laplacian approach for cortical thickness measurement due to changes in computational and acquisition parameters. We compared these results to two other methods widely used in clinical research using brain MRI data. Materials and Methods. Brain MRI scans were obtained in 10 healthy adults using three different sets of acquisition parameters. The first and the second acquisitions used different slice thickness but the same head position. The third scan was performed after head repositioning. We measured cerebral cortical thickness in all brain segmentations using three thickness methods: Laplacian, nearest distance, and the orthogonal projection. Results. The Laplacian method demonstrated the least variability with regard to the effect of interchange of boundaries, slice thickness, and repositioning of the head, compared with the other two methods. Conclusion. The Laplacian method is the most precise and reliable tool for in vivo cortical thickness measurement using brain MRI data.
Prevalence of White Matter Hyperintensities in a Young Healthy Population
Authors: Hopkins Ramona O. , Beck Callie J. , Burnett David L. , Weaver Lindell K. , Victoroff Jeff , Bigler Erin D. 
Published: October 2009

ABSTRACT Background and Purpose. White matter hyperintensities (WMHs) are bright objects observed in the white matter on brain magnetic resonance (MR) imaging. WMHs are often reported as “normal” findings but may represent pathological changes. The prevalence of WMHs appears to increase with increasing age although both the typical timing and clinical significance of their appearance among medically and neurologically healthy persons remains unclear. We assessed the prevalence of WMHs in a cohort of younger healthy subjects. Methods. Our study comprised 243 healthy subjects ages 16‐65 years from our prospective normative MR imaging database. MR scans were rated for presence of periventricular and centrum semiovale WMHs using a four‐point visual semi‐quantitative scale. Results. WMHs occurred in 5.3% (13 of 243) of subjects. All WMHs were small (rating of 0.5) except one subject age 65 years who had large WMHs (ratings of 2). The median age for subjects with no WMHs was 34.5 years compared to 57.0 years for subjects with WMHs. There were no gender differences (P= .76). Older age correlated with presence of WMHs (r= 0.24; P= .01). Age greater than 55 years had a 10‐fold increase in the prevalence of WMHs compared to age ≤55 years (odds ratio = 10.01; 95% confidence interval = 3.1‐32.3; P < .001). Conclusion. WMHs were uncommon in a younger healthy population screened for comorbid diseases, but increased 10‐fold in subjects over 55 years of age. When present, the WMHs are generally small (rating of 0.5). While large WMHs appear to be associated with cognitive deterioration, the optimum threshold for identification, clinical significance, and prognostic value of smaller white matter changes requires further research.
Diagnostic Accuracy of MRI for Middle Cerebral Artery Stenosis: A Postmortem Study
Authors: Chen Xiang‐Yan , Lam Wynnie Wai Man , Ng Ho Keung , Zhao Hai‐Lu , Wong Ka Sing 
Published: October 2009

ABSTRACT Background and Purpose. Magnetic resonance imaging (MRI) has been widely applied in detecting intracranial large artery stenosis, but there have been few validation studies to compare with histopathology. The aim of the postmortem study is to assess the accuracy of MRI in identifying middle cerebral artery (MCA) stenosis. Methods. We recruited, consecutively, Chinese postmortem autopsies in our hospital during 19 months. MRI was performed in the postmortem brains to scan the cross‐sections of MCAs with barium expanding the artery lumen. The MCAs were then removed for histopathologic studies. With histopathology as a reference standard, the accuracy of MRI was evaluated, and the correlation between MCA stenosis identified by MRI and radiologically or histopathologically evident brain infarcts was investigated. Results. Seventy‐six consecutive autopsies were recruited. The sensitivity and specificity of MRI in detecting more than 30% MCA stenosis were 38.6% and 92.2%, with a positive predictive value of 87.2% and negative predictive value of 52.2%, and the corresponding values of MRI in identifying more than 50% MCA stenosis were 57.1%, 90.8%, 50%, and 83.0%, respectively. Both more than 30% and more than 50% MCA stenosis identified by MRI were found to be associated with infarctions in the corresponding MCA territory (P= 0.001, odds ratio = 4.365, 95% CI: 1.684‐11.313; and P= 0.039, odds ratio = 2.694, 95% CI: 1.139‐6.377). Conclusions. Our study demonstrates the agreement between ex vivo MRI and histopathology in identifying MCA stenosis, and the correlation between the MCA stenosis identified by MRI and radiologically or histopathologically evident brain infarcts.
T2‐Weighted and T2 Relaxometry Images in Patients with Medial Temporal Lobe Epilepsy
Authors: Coan Ana Carolina , Bonilha Leonardo , Morgan Paul S. , Cendes Fernando , Li Li Min 
Published: October 2009

ABSTRACT Purpose. Quantification of increased T2‐weighted MRI signal that is associated with hippocampal sclerosis (HS) can be performed through (1) mean of hippocampal signal in single‐echo T2 MRI and (2) hippocampal T2 relaxometry. It is not clear whether these two techniques are equivalent. In this study, we compare the hippocampal signal, detected by single‐echo T2 quantification and by T2 relaxometry, in patients with medial temporal lobe epilepsy (MTLE). Methods. We studied magnetic resonance images from 50 MTLE patients and 15 healthy subjects. We compared the quantification of a T2 signal from single echo images to T2 relaxometry, both obtained from a manually traced region of interest (ROI) in coronal slices involving the whole hippocampus. Repeated measures ANOVA was used to evaluate the differences in the distribution of the Z‐scores from single‐echo T2 quantification and T2 relaxometry within subjects. Results. We observed a significant difference between the measurements obtained from single‐echo T2 quantification and T2 relaxometry (P < .001). Measurements from head, body, and tail of the hippocampus were different (P=.04), with a significant interaction between anatomic location and type of measurement used (P= .008). Post hoc paired comparisons revealed that T2 relaxometry yielded greater Z‐scores for the body (P= .002) and tail (P < .0001). Conclusions. For each subject with MTLE, T2 relaxometry was able to detect a higher signal in the body and tail of the hippocampus compared to single‐echo T2. This is a possible indicator that T2 relaxometry is more sensitive in detecting T2 abnormalities within the body and tail of the hippocampus in patients with MTLE.
Mapping the Relative Contribution of Gray Matter Activity vs. Volume in Brain PET: A New Approach
Authors: Berkouk K. , Quarantelli M. , Prinster A. , Landeau B. , Alfano B. , Baron J.C. 
Published: October 2009

ABSTRACTInterpretation of brain positron emission tomography (PET) in terms of function vs. structure is ambiguous owing to the partial volume effect (PVE). Therefore, observed differences in tracer distribution could reflect differences in either activity or volume, a problem that applies principally to gray matter (GM) since white matter (WM) virtually always has uniform activity. To assess the contribution of GM volume vs. activity, we implemented a method to directly compare PET images with underlying structure, and applied it to resting‐state 18Fluoro‐deoxy‐glucose‐PET (FDG) of healthy subjects. Methods. Average GM and WM PVE‐corrected mean FDG uptake values were applied onto co‐registered segmented magnetic resonance imaging data sets to generate a “virtual PET” in which activity is proportional to GM volume and resolution set to that of PET. The raw PET and virtual PET values were then compared across the sample of subjects, first voxel‐wise to detect clusters with significant activity–volume mismatch, and second within regions‐of‐interest (ROI) to quantify mismatches between unsmoothed voxel values. Results. Relative to volume, there was significant hyperactivity of most GM structures of the dorsal brain—except the thalamus—and significant hypoactivity of the temporal lobe, hippocampal region, and cerebellum, consistent across the voxel‐ and ROI‐based analyses. Conclusion. As applied to normals, our method documented the expected contribution of functional activity independently of local differences in GM volume in the normal pattern of FDG uptake, and disclosed marked heterogeneities in functional activity per unit GM volume among structures. This generic method should find applications in pathological states as well as for other PET and SPECT radiotracers.
Patients with Diffusion‐Perfusion Mismatch on Magnetic Resonance Imaging 48 Hours or More After Stroke Symptom Onset: Clinical and Imaging Features
Authors: Perez Angelica , Restrepo Lucas , Kleinman Jonathan T. , Barker Peter , Beauchamp Norman , Wityk Robert J. 
Published: October 2009

ABSTRACT Background. Abnormalities in diffusion‐weighted (DWI) and perfusion‐weighted (PWI) magnetic resonance imaging (MRI) are thought to reflect the presence of brain tissue at risk for ischemic stroke. Many patients with acute ischemic stroke have a mismatch pattern in which the PWI volume is larger than the DWI lesion. This mismatch typically resolves over 24‐48 hours. Little is known about the presence of DWI‐PWI mismatch in later stages of stroke. Methods. This is a retrospective study of 122 patients admitted with a diagnosis of acute ischemic stroke who had DWI and PWI abnormalities on studies performed within 7 days of onset of symptoms. Patients were divided into two groups: those with MRI performed <48 hours and those with MRI performed ≥48 hours from onset of symptoms. Results. Among 42 patients with MRI performed ≥48 hours after onset of stroke symptoms, 15 of 42 (36%) showed a mismatch pattern, compared to 45 of 80 (56%) in the <48 hours group (P < 0.05). Most of the patients in the ≥48 hours group with mismatch had large artery occlusive disease and many had neurological fluctuations. A subset of these patients were treated with induced hypertension and showed clinical improvement. Conclusions. Some patients have persistent DWI‐PWI mismatch up to several days after stroke onset. Further studies are needed to determine if these patients should be candidates for reperfusion therapy.
The Thickness and Texture of Temporal Bone in Brain CT Predict Acoustic Window Failure of Transcranial Doppler
Authors: Kwon Jee‐Hyun , Kim Jong S. , Kang Dong‐Wha , Bae Kyun‐Seop , Kwon Sun U. 
Published: October 2009

ABSTRACT Background and Purpose: Although transcranial Doppler (TCD) is useful for evaluation and treatment of ischemic stroke, temporal acoustic window failure (TAWF) limits its application. We performed this study to reveal whether initial brain CT of acute stroke patients predicted TAWF. Methods: We performed TCD in 92 acute ischemic stroke patients (57 males, aged 38‐84 years) with brain CT scans. We measured the thickness (BTW) and evaluated the texture of the temporal bone in acoustic windows shown in the CT scan with the use of picture archiving and communication system. The bone mineral density (BMD) of the vertebral bodies, femurs, and whole body was also measured. Results: Doppler signals were adequately obtained in 121 (65.8%) of the 184 middle cerebral arteries (MCA) from both cerebral hemispheres. BTW and inhomogeneity of temporal bone, besides age, sex, and hypercholesterolemia, was strongly correlated with TAWF. BMD was not directly correlated with TAWF, but inhomogeneous temporal bone was correlated with lower BMD scores. If the brain CT scan showed thick (BTW ≥ 2.7 mm) and inhomogeneous temporal bone, the possibility of TAWF was 93.5%, while if brain CT scan showed thin (BTW < 2.7 mm) and homogenous temporal bone, it was only 5.4%. Conclusions: The texture as well as the thickness of the temporal bone was the most important determinant of TAWF. When acute stroke patients had thin and homogeneous temporal bones in initial brain CT scan, TAWF was very rare, and loss of MCA signals on TCD specifcally indicated the absence of blood flow in MCA.
Stroke Caused by Small Vessel Occlusion in a Patient Taking Etoricoxib and Thalidomide
Authors: Wong Edward H.C. , Leung Thomas W.H. , Wong K.S. Lawrence 
Published: October 2009

ABSTRACTWe report a 33‐year‐old man with seronegative arthritis who had an acute infarct at the left lentiform nucleus while taking etoricoxib and thalidomide regularly. Extensive investigations did not find any evidence of large artery atherosclerosis, vasculitis, cardioembolic source or anti‐phospholipid antibodies. While it is possible that a short smoking history, hyperlipidemia, and the use of thalidomide could have contributed to the thrombosis of a small penetrator vessel, we postulated that the prolonged use of etoricoxib is another possible contributing factor.
Primary Percutaneous Transluminal Angioplasty for Early Moyamoya Disease
Authors: Rodriguez Gustavo J. , Kirmani Jawad F. , Ezzeddine Mustapha A. , Qureshi Adnan I. 
Published: October 2009

ABSTRACTMoyamoya disease is a progressive steno‐oclusive arteriopathy of the circle of Willis that manifests on cerebral angiography with a characteristic net of vessels at the base of the brain representing collateralization. Described initially in Japan where children present with cerebral ischemia and adults with hemorrhagic stroke, it was recognized to have a more benign course in the United States, mainly causing cerebral ischemic events in young adults. Medical treatment is not intended to stop the progression of the disease and surgery is not exempt of risks. We present a patient with early moyamoya disease in the United States in whom primary transluminal angioplasty, a less invasive procedure, was performed to treat the stenotic arteriopathy with good immediate and sustained clinical and angiographic results, without evidence of restenosis at the site of angioplasty 2 years later.
Nonspecific Perichondritis of the Lumbar Spine
Authors: Semnic Robert , Milosevic Biljana , Vuckovic Nada , Semnic Marija , Sener R. Nuri 
Published: October 2009

ABSTRACTA teenage girl with soft tissue inflammation involving the L2‐S1 region of the lumbar region is reported. Magnetic resonance (MR) imaging revealed high‐signal lesions on T2‐weighted images in association with contrast enhancement. Histology revealed nonspecific perichondritis with mononuclear inflammatory infiltration of the perichondrium and connective tissue. Six months after treatment, MR imaging was normal. No similar case of perichondritis with involvement of the lumbar region could be found in the current literature.
Cerebral Atrophy Measurement in Clinically Isolated Syndromes and Relapsing Remitting Multiple Sclerosis: A Comparison of Registration‐Based Methods
Authors: Anderson Valerie M. , Fernando Kryshani T.M. , Davies Gerard R. , Rashid Waqar , Frost Chris , Fox Nick C. , Miller David H. 
Published: October 2009

ABSTRACT Background and Purpose. Brain atrophy is a proposed marker of disease progression in multiple sclerosis (MS). Many magnetic resonance imaging‐based methods of atrophy quantification exist, but their relative sensitivity and precision is unclear. Our aim was to compare atrophy rates from the brain boundary shift integral (BBSI), structural image evaluation, using normalization of atrophy (SIENA) (both registration‐based methods) and segmented brain volume difference, in patients with clinically isolated syndromes (CIS), relapsing remitting MS (RRMS), and controls. Methods. Thirty‐seven CIS patients, 30 with early RRMS and 16 controls had T1‐weighted volumetric imaging at baseline and 1 year. Brain atrophy rates were determined using segmented brain volume difference, BBSI, and SIENA. Results. BBSI and SIENA were more precise than subtraction of segmented brain volumes and were more sensitive distinguishing RRMS subjects from controls. A strong correlation was observed between BBSI and SIENA. Atrophy rates were greater in CIS and RRMS subjects than controls (RRMS P < .001). With all methods, significantly greater atrophy rates were observed in CIS patients who developed clinically definite MS relative to subjects who did not. Conclusion. Registration‐based techniques are more precise and sensitive than segmentation‐based methods in measuring brain atrophy, with BBSI and SIENA providing comparable results.
Guidelines for Screening of Extracranial Carotid Artery Disease: A Statement for Healthcare Professionals from the Multidisciplinary Practice Guidelines Committee of the American Society of Neuroimaging; Cosponsored by the Society of Vascular and Interventional Neurology
Authors: Qureshi Adnan I. , Alexandrov Andrei V. , Tegeler Charles H. , Hobson Robert W. , Dennis Baker J. , Hopkins L. Nelson 
Published: October 2009

ABSTRACTThe aim of this new statement is to provide comprehensive and timely evidence‐based recommendations on the screening for asymptomatic carotid artery stenosis in the general population and selected subsets of patients. Recommendations are included for high‐risk persons in the general population; patients undergoing open heart surgery including coronary artery bypass surgery; patients with peripheral vascular diseases, abdominal aortic aneurysms, and renal artery stenosis; patients after radiotherapy for head and neck malignancies; patients following carotid endarterectomy, or carotid artery stent placement; patients with retinal ischemic syndromes; patients with syncope, dizziness, vertigo or tinnitus; and patients with a family history of vascular diseases and hyperhomocysteinemia. The recommendations are based on prevalence of disease, anticipated benefit, and concurrent guidelines from other professional organizations in selected populations.
Demonstration of Significant Resolution of Cerebral Sino‐Venous Thrombosis Associated with Intravenous Recombinant Tissue Plasminogen Activator
Authors: Misra Vivek , Elliott Debra G. , Gonzalez‐Toledo Eduardo , Kelley Roger E. 
Published: October 2009

ABSTRACTBACKGROUND Cerebral sino‐venous thrombosis (CVT) is commonly treated with anticoagulant therapy. There are reports of response to endovascular thrombolysis with or without mechanical aspiration in patients with clinical deterioration. CASE We present a 29‐year‐old man with acute onset of severe headache, found to have extensive CVT by magnetic resonance venography (MRV). His atypical presentation led to cerebral angiography that was complicated by global aphasia and right hemiparesis from left middle cerebral artery distribution ischemia. He received intravenous rt‐PA (recombinant tissue plasminogen activator) within an hour of the procedure followed, 24 hours later, by intravenous heparin infusion with significant clinical improvement. The headache severity and CVT, on follow‐up MRV, resolved significantly within 2 days. CONCLUSIONS We demonstrate clinical and neuroimaging response to systemic rt‐PA in CVT. Thrombolysis may have a role in CVT management with an extended therapeutic window.
Cranio‐Spinal Subdural Empyema due to S. Intermedius: a Case Report
Authors: Pompucci Angelo , De Bonis Pasquale , Sabatino Giovanni , Federico Giovanni , Moschini Massimo , Anile Carmelo , Mangiola Annunziato 
Published: October 2009

ABSTRACTBACKGROUND AND PURPOSE Subdural empyema represents a loculated infection between the dura and the arachnoid. It has been described either intracranially or in the spinal canal, the latter localization being quite rare. While treatment guidelines for a single (either brain or spinal) localization of a subdural empyema are more or less established, its management when a massive involvement of CNS is evident represents a challenge. METHODS The authors describe a unique case of a 65‐year‐old woman having a massive involvement of the entire CNS with multiple localizations, both intracranial and spinal. Early diagnosis was obtained through brain CT scans followed by cranio‐spinal contrast enhanced MRI scans. Patient was treated with external ventricular drainage and suboccipital craniectomy, while on antibiotic therapy. RESULTS Patient's neurological condition gradually improved. By the end of the eighth hospital week, she was discharged without any neurological deficit. CONCLUSIONS Spinal subdural empyema and brain subdural empyema are not always, as in our case, two different entities. Prompt diagnosis and treatment constitute the major variables affecting outcome.
MRI Changes in Thrombotic Microangiopathy Secondary to Malignant Hypertension
Authors: Garewal Mandeep , Yahya Sofia , Ward Christopher , Singh Niranjan , Cruz‐Flores Salvador 
Published: October 2009

ABSTRACTThrombotic microangiopathy with thrombocytopenia and intravascular hemolysis are characteristic of three disorders: malignant hypertension (MH), disseminated intravascular coagulation (DIC), and thrombocytopenic thrombotic purpura (TTP). We describe a patient with thrombotic microangiopathy secondary to malignant hypertension that caused extensive bilateral cortical ischemic infarction.