bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetization Transfer Magnetic Resonance Imaging in the Assessment of Neurological Diseases
Authors: Filippi Massimo , Rocca Maria A. 
Published: November 2009

ABSTRACTIn several white matter diseases of the central nervous system (CNS), and in particular in multiple sclerosis, conventional magnetic resonance imaging (MRI) has proved to be sensitive for detecting lesions and their changes over time. However, con ventional MRI is not able to characterize and quantify the tissue damage within and outside such lesions. Magnetization transfer MRI (MT‐MRI) is a quantitative MRI technique with the potential to overcome this limitation and, as a consequence, to provide additional information about the nature and the extent of tissue damage. Metrics derived from MT‐MRI can quantify the structural changes occurring within and outside lesions visible on conventional MRI scans. The present review summarizes the major contributions given by MT‐MRI to provide an accurate in vivo picture of the heterogeneity of CNS pathology and, ultimately, to improve our ability to monitor the evolution of various neurological conditions.
The Accuracy of Transcranial Doppler in the Diagnosis of Stenosis or Occlusion of the Terminal Internal Carotid Artery
Authors: Navarro Jose C. , Mikulik Robert , Garami Zsolt , Alexandrov Andrei V. 
Published: November 2009

ABSTRACT Background and Purpose. Transcranial Doppler (TCD) can detect intracranial stenoses and occlusions that can help in the diagnosis and management of ischemic stroke. The accuracy parameters for lesions located in the terminal internal carotid artery (TICA) are less known, unlike other basal cerebral vessels. Patients and Methods. The authors studied consecutive patients referred for TCD who underwent contrast angiography or magnetic resonance angiography. They calculated the sensi tivity, specificity, positive and negative predictive values (PPV and NPV), and likelihood ratios. Results. Forty‐three patients had TCD and angiography: mean age was 57 ± 20 years, and 65% were men. Twenty‐two patients were diagnosed with TICA stenosis or occlusion on TCD underwent angiography. Four patients had abnormal TCD findings that were not confirmed by angiography. Two of 21 patients with normal TCD showed mod erate (< 50%) stenosis of the TICA and cavernous segment of the internal carotid artery at angiography. Accuracy parameters for TCD were as follows: sensitivity = 90% (confidence interval [CI], 63%‐96%), specificity = 83% (CI, 61%‐94%), PPV = 82%, NPV = 86%, positive likelihood ratio = 5, and negative likelihood ratio = 0.17. Conclusions. TCD is a sensitive screening tool for the lesions in the TICA. Specificity is likely affected by a wide spectrum of the stenosis severity shown at angiography and time lags between the studies.
Ictal Single‐Photon Emission Computed Tomography Imaging in Extra Temporal Lobe Epilepsy Using Statistical Parametric Mapping
Authors: Knowlton Robert C. , Lawn Nicholas D. , Mountz James M. , Buddhiwardhan Ojha , Miller Suzanne , Burneo Jorge G. , Kuzniecky Ruben I. 
Published: November 2009

ABSTRACT Purpose. To examine the application of statistical parametric mapping (SPM) to analyze ictal single‐photon emission computed tomography (SPECT) scans in surgical candidates with extratemporal lobe epilepsy. Methods. The authors selected patients who underwent successful ictal SPECT acquisition in the process of surgical treatment of intractable partial epilepsy. Thirteen patients were identified who met inclusion criteria for confident seizure localization from either intracranial electroencephalogram recordings or epilepsy surgery outcome. In these cases, ictal scans were registered to an in‐house‐developed normal SPECT atlas composed of 14 spatially normalized brains of normal subjects. SPM96 was used to test on a voxel‐by‐voxel basis for statistically significant increases in blood flow associated with each patient's ictal scan. The results were then mapped back onto the patient's magnetic resonance image (MRI) for final interpretation. Statistical parametric mapping (SPM) analysis of ictal SPECT scans was compared to both conventional visual interpretation and the analysis of subtraction ictal SPECT co‐registered to MRI (SISCOM). Results. Ten of 13 patient scans showed localizing focal ictal increases in regional cerebral blood flow, all of which were concordant with ultimate epilepsy localization. Of the 3 cases not localized with SPM, 1 was localized by conventional visual interpretation and another, not localized by visual interpretation, was correctly localized with SISCOM. Two cases not localized by SISCOM were localized by both visual and SPM analysis. Conclusions. This work provides supportive evidence for proof of principle that SPM can be used to provide objective, accurate analysis of ictal SPECT scans in patients with extratemporal lobe epilepsy.
Transcranial Doppler in Asymptomatic Carotid Stenosis Representing Hemodynamic Impairment: Correlation Study with Magnetic Resonance Imaging
Authors: Kim Dong Wook , Min Ju‐Hong , Lee Yong‐Seok 
Published: November 2009

ABSTRACT Background and Purpose. Since the benefit of an endarter ectomy in an asymptomatic carotid stenosis is not as clear as that in symptomatic stenosis, identifying patients with a high risk of stroke will allow the improved selection of surgical candidates. To evaluate the role of transcranial Doppler (TCD) in assessing an asymptomatic stenosis, this study examined the association of a TCD‐detected hemodynamic change with a stenosis‐related abnormality on magnetic resonance imaging (MRI). Methods. Asymptomatic patients with a more than 60% internal carotid artery stenosis were enrolled in this study. The hemodynamic change in the TCD was analyzed in terms of the demographic characteristics, the stroke risk factors, and the stenosis‐related MRI abnormalities that are a proven risk factor of a further stroke. Results. Fifty‐three patients were retrospectively recruited. While there were no differences in the demo graphic characteristics or frequency of the stroke risk factors, the proportion of patients with stenosis‐related MRI abnormality was significantly higher in patients with a hemodynamic change on TCD (13/19 vs 6/34, P < .01; odds ratio = 10.11; 95% confidence interval = 2.73–37.4). Conclusions. The TCD‐detected hemodynamic changes may provide useful information for assessing the frequency of silent stroke in patients with an asymptomatic carotid stenosis.
Three‐Dimensional Contrast‐Enhanced Magnetic Resonance Angiography of Carotid Artery after Stenting
Authors: Teng Michael M. H. , Tsai Fong , Liou Adrian Jy‐Kang , Lirng Jiing‐Feng , Chang Feng‐Chi , Luo Chao‐Bao , Cheng Hui‐Cheng 
Published: November 2009

ABSTRACT Purpose. This study presents 3‐dimensional, contrast‐enhanced, magnetic resonance (MR) angiographic appearances of the carotid artery after stenting. Methods. The authors reviewed contrast‐enhanced MR angiograms of 18 carotid arteries in 13 patients. These arteries were not stenotic or occluded in the stented segment, as shown on carotid angio‐grams (11 patients) or carotid Doppler images (2 patients) obtained later. Results. Five patients had 1 stent in each of their bilateral carotid arteries. One patient with 1 stent in 1 artery underwent the examination twice with different MR coils. Different artifact patterns were found in 19 carotid‐stent examinations. Type 1a involved short segments of false narrowing or false focal occlusion at both ends of the stent (n = 12); the carotid artery in the stented segment between the ends was normal. Types 2a and 2b occurred along the stented segment of the artery between the 2 ends of the stent. Type 2a was milder, with segmental faint signal intensity or luminal stenosis in the entire length of the stented segment (n = 5). Type 2b was total loss of luminal signal intensity over the whole length of the stented segment (n = 2). Last, type 1b was a band of hyperintensity at the ends of type 2a or 2b artifacts. Types 1a and 1b were due to susceptibility effect, and types 2a and 2b were from radio‐frequency shielding effect. Both of these effects were identified in MR angiogram of nitinol stents and stainless steel stents. Conclusion. Awareness of these artifacts is essential to prevent misdiagnosis.
Power M‐Mode Transcranial Doppler for Diagnosis of Patent Foramen Ovale and Assessing Transcatheter Closure
Authors: Spencer Merrill P. , Moehring Mark A. , Jesurum Jill , Gray William A. , Olsen John V. , Reisman Mark 
Published: November 2009

ABSTRACT Background and Purpose. Transcatheter closure of patent fora men ovale (PFO) can benefit from a less invasive diagnostic method than transesophageal echocardiography (TEE). Thirty‐three gate power m‐mode transcranial Doppler (pmTCD) was evaluated for its accuracy in diagnosis of PFO and utility in evalu ating residual intracardiac right‐to‐left shunt (RLS) following transcatheter closure. Methods. The sensitivity of pmTCD and single‐gate TCD (sgTCD) to detect contrast bubble emboli through RLS was compared during transcatheter PFO closure. During 100 preclosure diagnostic evaluations and in 81 postclosure assessments, embolic tracks on pmTCD were counted following intravenous contrast injections and were graded using a 6‐level logarithmic scale. The accuracy of TEE and pmTCD was separately compared to PFO anatomical find ings during transcatheter closures. Results. There were signifi cantly more microemboli detectable on pmTCD (322 ± 166; 95% confidence interval [CI], 388–257) than on sgTCD (186 ± 109; 95% CI, 229‐143; P < .001). McNemar change tests sug gest that the diagnostic capabilities of pmTCD and TEE for detecting PFO are comparable and correspond to the anatomi cal findings determined during cardiac catheterization (P= .69 and .45, respectively). During 6‐month postclosure evaluation (mean = 185 days), 66% of the patients demonstrated success ful closure without significant RLS (ie, grades 0, I, or II), and 34% were found to have incomplete closure with significant RLS (ie, grades III, IV, or V). Conclusions. pmTCD provides greater sensitivity to contrast bubble emboli than does sgTCD. Among candidates for transcatheter closure, pmTCD provides an improved noninvasive method for diagnosing PFO and evaluating transcatheter closure.
Contralateral Cerebral Blood Flow Velocity Changes after Intracarotid Amobarbital Injection
Authors: Pfefferkorn T. , Hundt C. , Arnold S. , Missler U. , Noachtar S. , Hamann G. F. 
Published: November 2009

ABSTRACT Background and Purpose. The intracarotid amobarbital procedure (IAP) leads to a prompt decrease in ipsilateral middle cere bral artery (MCA) mean blood flow velocity (MFV). Little is known about contralateral MFV changes. Methods. The authors investigated bilateral MCA MFV using transcranial Doppler sonography (TCD) in 8 patients with epilepsy undergoing IAP. Measurements were excluded from analysis if angiography revealed any signs of interhemispheric cross‐flow. Results. With in 64 seconds after amobarbital injection, ipsilateral MFV decreased to a mean of 44.4%± 7.5% of baseline value (P < .01). In the absence of interhemispheric cross‐flow and within 68 seconds, contralateral MFV decreased to 83.1%± 7.9% (P < .01). Conclusions. The observed decrease of contralateral MFV was not caused by amobarbital cross‐perfusion. A possible underlying mechanism may be interhemispheric deafferentation.
Reversible Cerebellar Lesions Induced by Metronidazole Therapy for Helicobacter Pylori
Authors: Ito Hirono , Maruyama Michiyuki , Ogura Naoko , Fujioka Toshiki , Iwasaki Yasuo , Aikawa Atsushi , Hasegawa Akira 
Published: November 2009

ABSTRACTMetronidazole is widely used for chronic or refractory infection and has recently also been used for the treatment of Helicobacter pylori. The authors report the case of a Japanese patient presenting with reversible cerebellar lesions induced by prolonged administration of metronidazole for treatment of H pylori with magnetic resonance imaging findings. Although rare, prolonged and high‐dose administration of metronidazole may induce cerebellar lesions. Increased awareness of this phenomenon is important, as these lesions are reversible with discontinuation of this drug.
Novel Neuroimaging Findings in a Patient with Cerebral Whipple's Disease: A Magnetic Resonance Imaging and Positron Emission Tomography Study
Authors: Galldiks N. , Burghaus L. , Vollmar S. , Cizek J. , Impekoven P. , Thomas A. , Jacobs A. H. , Herholz K. 
Published: November 2009

ABSTRACTThe authors report a 43‐year‐old patient with histopathologically proven cerebral Whipple's disease. Magnetic resonance imaging (MRI) revealed a multilayered left frontal lesion without mass effect, no perifocal brain edema, no contrast enhancement, and a thin shell of fluid signal that presented as an incomplete, open ring. An [C]methionine positron emission tomography (PET) study showed low uptake below the threshold that is characteristic for brain tumors. In precise co‐registration to the MR images, the PET data showed that increased uptake was mainly located in the direct adjacent part of the MRI lesion. The fluid signal on MRI corresponded to the extensive outflow of fluid from the lesion, which was observed during neurosurgical resection, and also to the neuropathological findings. The authors conclude that this cerebral manifestation of Whipple's disease made a unique and hitherto undescribed appearance on MRI; uptake pattern of PET amino acid tracer may help in the preoperative distinction of inflammatory from neoplastic lesions.
Anatomical Functional Changes in a Patient Presenting a Complex Malformation of Cortical Development
Authors: Calistri Valentina , Lenzi Delia , Gilio Francesca , Di Bonaventura Carlo , Inghilleri Maurizio , Mainero Caterina , Pantano Patrizia 
Published: November 2009

ABSTRACTThe authors describe a case of right fronto‐parietal micropoligyria associated with small schizencephaly clefts and the presence of a frontal open‐lip schizencephaly with corpus callosum agenesis. A functional magnetic resonance imaging (fMRI) study was performed to evaluate the possible reorganization of cortical functions in a patient presentinga complex malformation pattern and to investigate which cortical areas were activated during left finger movements. An fMRI study was performed during the execution of a repetitive index finger‐to‐thumb opposition movement with the right hand and the left hand in 2 separate sessions. Movement of the right hand induced a normal motor activation pattern involving the contralateral left sensory‐motor cortex. Movement of the left hand produced significant activation of brain cortex. This fMRI study highlights the compensatory role of the ipsilateral cortical pathways in hand movements in the case of a complex brain malformation that involves the main motor activation areas.
Atrophy of the Brain and Spinal Cord in Multiple Sclerosis
Authors: Bakshi Rohit 
Published: November 2009

ABSTRACTThe destructive nature of the multiple sclerosis disease process is of growing clinical and neuroscientific interest. Axonal transection, neuronal loss, Wallerian degeneration, and chronic demyelination likely contribute to macroscopic atrophy of the brain and spinal cord in patients with the disease. This neurodegenerative process belies the traditional view of multiple sclerosis as an inflammatory demyelinating disease. Magnetic resonance imaging is a key tool in the diagnosis and longitudinal monitoring of central nervous system atrophy. This supplement to theJournal of Neuroimaging is devoted to brain and spinal cord atrophy in MS, with a focus on the role of magnetic resonance imaging. The authors and topics of the articles have been chosen by the Guest Editor to provide a state‐of‐the‐art review of this important field. An emphasis is placed on several key issues pertaining to central nervous system atrophy in multiple sclerosis: pathogenesis, magnetic resonance imaging techniques for quantification, clinical relevance, and effects of disease‐modifying therapies.
Magnetic Resonance Imaging Surrogates of Multiple Sclerosis Pathology and Their Relationship to Central Nervous System Atrophy
Authors: Meier Dominik S. , Weiner Howard L. , Khoury Samia J. , Guttmann Charles R. G. 
Published: November 2009

ABSTRACTThis article focuses on the various magnetic resonance imaging metrics currently used in multiple sclerosis and discusses how they relate to central nervous system atrophy. The authors discuss the significance of T2 lesion burden, gray matter damage, T1 hypointense lesions (black holes), contrast‐enhanced lesions, magnetization transfer imaging, diffusion imaging, and magnetic resonance spectroscopy. These magnetic resonance imaging surrogates exhibit different sensitivities for each of the underlying pathogenic processes of multiple sclerosis. By exploiting the complementary nature and varying sensitivities of these magnetic resonance imaging surrogates, it is possible to create a more comprehensive picture of the degenerative process of multiple sclerosis.
Ultrasound Contrast Agents for Brain Perfusion Imaging and Ischemic Stroke Therapy
Authors: Martina Alberto Della , Meyer‐Wiethe Karsten , Allémann Eric , Seidel Günter 
Published: November 2009

ABSTRACTStroke is one of the major causes of death and disabilities in industrialized countries. Ultrasound imaging is a largely wide spread bedside technique that is easily accessible and valuable in case of emergency but suffers from the fact that the ultrasound wave has to cross the skull for brain imaging. However, ultrasound contrast agents and new contrast‐specific imaging modalities have helped to improve the diagnostic quality of transcranial ultrasonography. This review article surveys and discusses the current state of microbubbles technology and the use of contrast‐enhanced transcranial ultrasound for the assessment of brain perfusion. Future aspects and expecta tions in contrast agent functionality, such as targeting and drug or gene delivery, acceleration of thrombolysis, and imaging technology, are also discussed.
Isotropic Component Trace Analysis
Authors: Matsuzawa Hitoshi , Nakayama Naoki , Kwee Ingrid L. , Nakada Tsutomu 
Published: November 2009

ABSTRACTA new method for analyzing diffusion tensor imaging (DTI) of the brain, based on a recently introduced algorithm, lambda chart analysis (LCA), is presented. Pretreatment of a given DTI data set with LCA, which effectively segregates isotropic and aniso tropic components, allows for total removal of the anisotropic component from the DTI data set. The remaining pure isotropic component can therefore be subjected to further analysis simi lar to that applied in the trace histogram method. Deconvolution of the trace function yielded 3 Gaussian elements. Remapping of these 3 deconvoluted isotropic elements back onto the 2‐dimensional image plane provided anatomical correlates of each element. The algorithm, referred to here as isotropic com ponent trace analysis, can be used as a pictorial analytic tool, as well as a numerical analytical tool, for the noninvasive assess ment of isotropic parenchymal components. The presented method provides quantitative indices of certain parenchymal parameters with better clarity than currently available methods. A ready‐to‐use program, EZ‐LCA, for this powerful method is provided (available at http://coe.bri.niigata‐u.ac.jp).
Clinical and Angiographic Results of Dilatation Procedures for Symptomatic Intracranial Atherosclerotic Disease
Authors: Qureshi Adnan I. , Suri M. Fareed K. , Siddiqui Amir M. , Kim Stanley H. , Boulos Alan S. , Ringer Andrew J. , Lopes Demetrius K. , Guterman Lee R. , Hopkins L. Nelson 
Published: November 2009

ABSTRACT Background and Purpose. The authors determined the techni cal success and the clinical and angiographic results of angioplasty and/or stent placement for intracranial atherosclerotic disease (ICAD) at a tertiary‐care referral hospital. Methods. Angiographic and clinical outcomes occurring within the 1‐month follow‐up interval were recorded. Patients were fol lowed up for a mean period of 20.5 ± 9.2 months, and a neurovascular imaging study was performed in 18 of the 21 patients alive after a mean period of 19.7 ± 9.2 months. Stroke‐free survival and ipsilateral stroke‐prevention rates were esti mated using Kaplan Meier analyses. Results. Twenty‐four patients (mean age = 61.0 ± 13.5 years; 15 were men) underwent 30 procedures for treatment of ICAD. The procedures included angioplasty (n = 18) and attempted primary stent placement (n = 14). In 2 procedures, angioplasty was performed in the same session after unsuccessful stent placement. There was immediate stenosis reduction (mean ± SD) from 84%± 17% to 27%± 21%. The overall 1‐month composite rate of major stroke, death, and major bleeding complications was 7% for the 30 procedures. Overall stroke‐free survival at 36 months was estimated as 79% (95% confidence interval, 57%‐91%), and the ipsilateral stroke‐prevention rate was estimated to be 87% (95% confidence interval, 65%‐95%). Among the 15 patients who underwent repeat angiography, restenosis requir ing second intervention was observed in 1 patient. No restenosis could be identified in 3 patients who underwent com puted tomographic or magnetic resonance angiography. Con clusion. This single‐center study demonstrates the feasibility and effectiveness (for secondary stroke prevention) of angioplasty and/or stent placement for treatment of ICAD.
Catheter‐Based Aortography Fails to Identify Aortic Atherosclerotic Lesions Detected on Transesophageal Echocardiography
Authors: Khatri Ismail A. , Mian Nimer , Alkawi Ammar , Janjua Nazli , Kirmani Jawad F. , Saric Muhamed , Levine Jason C. , Qureshi Adnan I. 
Published: November 2009

ABSTRACT Background and Purpose. Transesophageal echocardiography is used to detect the aortic arch pathology during diagnostic workup of ischemic stroke events. Conventional angiography is increasingly used in diagnosing and treating atherosclerotic vas cular lesions in patients with ischemic stroke. Although catheter‐based aortography can be performed with cerebral angiography, there is limited information about the utility of aortography in identifying atherosclerotic abnormalities of the aortic arch. Methods. A retrospective chart review was performed to identify patients who underwent aortography as part of their angio‐graphic study and transesophageal echocardiography. Both studies were reviewed independently in the absence of knowl edge of the results of the other study. The findings of these aortograms were correlated with the findings of transesophageal echocardiography. Results. A total of 34 patients underwent both aortography and echocardiography. Of a total of 34 trans esophageal echocardiograms, 29 showed abnormal findings in the aorta (85%) and 5 appeared normal (15%). These aortic abnormalities included mild to moderate atherosclerosis in 18 cases (52%), moderate to severe atherosclerosis in 4 cases (12%), and severe atherosclerosis in 7 cases (21%). None of these abnormalities were detected by aortography. No disease was visualized in the origin of the supraaortic arteries. Conclusions. Aortic arch atherosclerosis is common in patients with ischemic stroke; however, aortograms acquired during conventional angiography fail to identify abnormalities detected on transesophageal echocardiogram.