bluuebunny/crossref_metadata_2025 huggingface dataset:
Paradoxical Brain Embolism as a Cause of Central Retinal Artery Occlusion: A Case Report
Authors: Hayashi Koji , Iguchi Yasuyuki , Kimura Kazumi , Shibazaki Kensaku , Kobayashi Kazuto , Inoue Takeshi
Published: October 2009

A 79‐year‐old right‐handed woman was admitted to hospital following sudden onset of severe visual loss in the left eye. Left central retinal artery occlusion (CRAO) was diagnosed. Diffusion‐weighted imaging showed an asymptomatic hyperintensity in left middle cerebral artery territory. Transcranial Doppler and transesophageal echocardiography revealed patent foramen ovale. No other embolic sources were identified in the carotid artery, aortic arch, or heart. We report herein a case of CRAO caused by paradoxical brain embolism.
Clinical and MRI Predictors of Outcome After Surgical Intervention for Cervical Spondylotic Myelopathy
Authors: Alafifi T. , Kern R. , Fehlings M.
Published: October 2009

BACKGROUND

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction in older individuals. Controversy remains in terms of the optimal timing and indications for surgical intervention. In this context, it would be of benefit to define clinical and magnetic resonance imaging (MRI) predictors of outcome after intervention for CSM.

OBJECTIVE

We studied subjects with clinically documented cervical myelopathy to evaluate the relationship among preoperative MRI signal change, clinical findings, and outcome after surgical intervention.

METHODS

We performed a retrospective case study of 76 CSM patients who underwent cervical decompressive surgery and who had pre‐ and postoperative MRI studies available for review. Preoperative clinical findings and MRI abnormalities on T1‐ (T1WI) and T2‐weighted (T2WI) images were correlated with outcomes (Nurick scores; Odom's criteria) following surgical intervention. Postoperative MRIs were performed 2‐4 months postsurgery to assess for adequacy of decompression and resolution of preoperative signal changes. The pattern of spinal cord signal intensity was classified as: Group A (MRI N/N), no intramedullary signal intensity abnormality on T1WI or T2WI; Group B (MRI N/Hi), no intramedullary signal intensity abnormality on T1WI and high intramedullary signal intensity on T2WI; Group C (MRI Lo/Hi), low intensity intramedullary signal abnormality on T1WI and high intensity intramedullary signal abnormality on T2WI. Statistical analyses were performed using SAS (version 8.2).

RESULTS

We evaluated 76 patients (57% males, mean age 62 years, range 30‐89) who experienced preoperative symptoms for an average of 6.5 months (range 1 month to 9 years). Preoperative MRI studies demonstrated the following: Group A (MRI N/N) = 45; Group B (MRI N/Hi) = 23; and Group C (MRI Lo/Hi) = 8. The mean postoperative follow‐up period was 2.5 years (range 2 months to 8.5 years). A positive Babinski sign and the presence of intrinsic hand muscle atrophy showed the greatest association with abnormal preoperative MRI signal change. High preoperative Nurick score, clonus, and leg spasticity were associated with a less favorable postoperative outcome. In Group B (MRI N/Hi), 11/23 (52.17%) patients had recovery to MRI N/N (P < .0001) at their follow‐up scan.

CONCLUSIONS

Patients with high intramedullary signal change on T2WI who do not have clonus or spasticity may experience a good surgical outcome and may have reversal of the MRI abnormality. A less favorable surgical outcome is predicted by the presence of low intramedullary signal on T1WI, clonus, or spasticity. These data suggest that there may be a window of opportunity to obtain optimal surgical outcomes in patients with CSM.
Intra‐Arterial Thrombolysis for Central Retinal Artery Occlusion in United States: Nationwide In‐Patient Survey 2001‐2003
Authors: Suri M. Fareed K. , Nasar Abu , Hussein Haitham M. , Divani Afshin A. , Qureshi Adnan I.
Published: October 2009

BACKGROUND

Intra‐arterial thrombolysis (IAT) has been used as a treatment modality for central retinal artery occlusion (CRAO). However, national estimates of such practice and associated outcomes are not available. We performed this study to determine the frequency and outcomes of thrombolysis among adult patients hospitalized in United States (US) for CRAO.

METHODS

We determined the rates, hospital outcomes, and hospital charges incurred for patients with CRAO treated with thrombolysis using Nationwide Inpatient Survey (NIS) and compared them with patients treated without thrombolysis. NIS is the largest all‐payer inpatient care database in the US approximating a 20‐percent stratified sample of US community hospitals.

RESULTS

There were 1379 admissions for primary diagnosis of CRAO in 2001‐2003. IAT was used in 27(1.9%) of the patients with CRAO. There was no in‐hospital mortality or intracranial hemorrhage reported among any patient with CRAO treated with thrombolysis. All patients treated with IAT were discharged home. IAT was exclusively used in urbanteaching hospitals.

CONCLUSIONS

There is potential of benefit from IAT in CRAO, which is only offered in certain centers. Clinical trials are needed to demonstrate this beneficial effect.
Magnetization Transfer MRI in Multiple Sclerosis
Authors: Filippi Massimo , Agosta Federica
Published: October 2009

In multiple sclerosis (MS), conventional magnetic resonance imaging (cMRI) has proved to be sensitive for detecting lesions and their changes over time. However, cMRI is not able to characterize and quantify the tissue damage within and outside such lesions. Magnetization transfer (MT) MRI is a quantitative 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 associated to this disease.

During the last 10 years, MT MRI indeed has allowed us to quantify the structural changes occurring within and outside lesions visible on cMRI scans, thus providing a more accurate in vivo picture of the heterogeneity of MS and, as a consequence, improving our ability to monitor the evolution of the disease. The application of MT MRI to the study of MS has contributed to change our understanding of how MS causes irreversible disability by showing that MS is more than an inflammatory‐demyelinating condition of the white matter of the central nervous system.
Diffusion Tensor MRI in Multiple Sclerosis
Authors: Rovaris Marco , Filippi Massimo
Published: October 2009

During the last 10 years, thanks to the development of sophisticated acquisition schemes and the application of novel image analysis and postprocessing, diffusion tensor (DT) magnetic resonance imaging (MRI) has increasingly been applied to the study of multiple sclerosis (MS). DT MRI proved to be able to detect and quantify tissue damage within and outside T2‐visible MS lesions. In addition, DT MRI has been shown to be sensitive to the evolution of MS damage over short‐term periods of time, and therefore holds promise to provide us with in vivo correlates of MS clinical severity, as well as predictors of long‐term disease evolution. Recent developments of the technique, such as DT tractography, are likely to improve dramatically our understanding of the mechanisms associated to the accumulation of MS disability. Unresolved issues to be addressed include the definition of the actual features underlying diffusion changes in MS and the potential of DT MRI in the differential diagnosis between MS and other demyelinating conditions. The best acquisition and postprocessing strategies for DT MRI studies of MS also remain a matter of debate. Moreover, the precision and accuracy of DT MRI scans in detecting longitudinal, MS‐related changes need to be further investigated. This is a pivotal issue for a future application of DT MRI to the monitoring of MS evolution in large‐scale clinical trials and, possibly, in individual patients.
MR Spectroscopy in Multiple Sclerosis
Authors: De Stefano Nicola , Filippi Massimo
Published: October 2009

In the last decade, the use of magnetic resonance imaging (MRI) has led to a reevaluation of the pathogenesis and the natural history of multiple sclerosis (MS). This has been driven to a significant degree by results of proton magnetic resonance spectroscopy (1H‐MRS) studies. By providing evidence of early neurodegeneration (based on levels of N‐acetylaspartate), results of 1H‐MRS studies have led to a reconsideration of the role of axonal damage in MS. By measuring brain changes of metabolites such as choline and myo‐inosol, 1H‐MRS has confirmed the importance of assessing myelin damage and repair. However, despite the pathological specificity of 1H‐MRS and the relatively large number of clinical 1H‐MRS studies on patients with MS, measures provided by this MR technique are not used routinely for assessing and monitoring MS patients. This is due to technical difficulties and limitations that are at present not entirely solved. We will review here the most relevant results in MS studies that have used 1H‐MRS measures, the clinical importance of these results and the pending issues that need to be solved for a larger and more reliable use of 1H‐MRS in clinical MS studies.
MRI of Spinal Cord in Multiple Sclerosis
Authors: Agosta Federica , Filippi Massimo
Published: October 2009

The spinal cord is a clinically eloquent region, whose damage has the potential to affect dramatically the functional outcome of patients with multiple sclerosis (MS). During the last 10 years, thanks to the development of sophisticated magnetic resonance imaging (MRI) techniques, MRI of the spinal cord has been made feasible and contributed significantly to increase the confidence in the diagnostic work‐up of patients suspected of having MS and to grade the severity of overall central nervous system (CNS) damage associated to the disease. Technical development in acquisition and postprocessing of spinal cord MRI is likely to increase in the near future our understanding of disease pathobiology through an increased ability to define the nature and location of spinal cord damage as well as through an accurate functional mapping of its activity, which might have an adaptive role in limiting the consequences of structural CNS injury due to MS.
MRI to Monitor Treatment Efficacy in Multiple Sclerosis
Authors: Fazekas Franz , Soelberg‐Sorensen Per , Comi Giancarlo , Filippi Massimo
Published: October 2009

It is the primary goal of disease modifying treatments in multiple sclerosis (MS) to prevent the occurrence of new clinical deficits and lessen or prevent accumulation of disability. As a consequence, clinical aspects constitute the major outcome variables in treatment trials and are also the leading factor for treatment decisions in individual patients. However, determining treatment efficacy by clinical evaluation suffers from limited objectivity, sensitivity, and specificity for the underlying pathophysiologic aspects, which may constitute the target of a given therapy. Magnetic resonance imaging (MRI) can partly overcome these limitations by showing morphologic aspects of the disease with clinical relevance and responsiveness to therapy. Within the past 10 years sufficient data have been collected to establish the accumulation of new/enlarging T2 lesions and gadolinium enhancing lesions, T2 lesion load, T1‐hypointense lesions, and brain volume changes as reasonably well‐defined markers of disease processes, which may serve to monitor treatment efficacy. Accordingly, these variables have been extensively used for probing the efficacy of disease modifying treatments. In part they are also suited to guide therapeutic decisions in the individual patient. Further options may come from the use of advanced techniques like magnetization transfer MRI, diffusion‐weighted MRI, and proton magnetic resonance spectroscopy, which detect more subtle MS related tissue abnormalities. Irrespective of the technique employed, great care has to be given to the standardization and reproducibility of both data acquisition and interpretation when using MRI to monitor treatment efficacy. For the individual patient therapeutic decisions based on MRI need experience and caution.
Statistical Issues Related to the Use of MRI Data in Multiple Sclerosis
Authors: Sormani Maria Pia , Filippi Massimo
Published: October 2009

Since magnetic resonance imaging (MRI) of the brain has proved to be the most important paraclinical tool for diagnosing multiple sclerosis (MS) and monitoring its evolution, methodological and statistical issues related to the use of MRI markers in MS have been the focus of several studies in the past 10 years. While many of these methodological issues have been addressed using standard procedures available from other areas of application of medical statistics, in some cases statistical procedures that are not standard have been developed specifically for MRI variables in MS. Two of the major achievements in the statistical methods applied to the use of MRI variables in MS in the past 10 years were the identification of a parametric model to describe the distribution of MRI lesion counts across patients and the study of the relationships between MRI markers and clinical variables, with the aim to validate MRI parameters as surrogates for clinical progression.
MRI Assessment Followed by Successful Mechanical Recanalization of a Complete Tandem (Internal Carotid/Middle Cerebral Artery) Occlusion and Reversal of a 10‐Hour Fixed Deficit
Authors: Ionita Catalina C. , Yamamoto Junichi , Tummala Ramachandra P. , Levy Elad I.
Published: October 2009

BACKGROUND

Mechanical clot extraction up to 8 hours after stroke onset is an alternative strategy for opening large vessels, especially for patients ineligible for intravenous thrombolysis. Safety beyond this therapeutic window is untested.

METHODS

An 81‐year‐old woman presented 8 hours after she developed left‐sided weakness and dysarthria with a National Institutes of Health Stroke Scale (NIHSS) score fluctuating between 6 and 13. Neuroimaging revealed a large perfusion deficit with no diffusion abnormalities. An emergent cerebral angiogram revealed a complete internal carotid artery terminus occlusion.

RESULTS

Successful mechanical thrombectomy was performed without complication and resulted in almost complete reversal of the patient's deficit to an NIHSS score of 1, 10 hours after stroke onset.

CONCLUSION

Patients with large hypoperfused areas and minimal diffusion abnormalities on the MRI may benefit from mechanical thrombectomy beyond an 8‐hour window.
Early Dynamic SPECT Imaging in Acute Viral Encephalitis
Authors: Kataoka Hiroshi , Inoue Makoto , Shinkai Takayuki , Ueno Satoshi
Published: October 2009

BACKGROUND AND PURPOSE

Several cases have reported that dynamic single‐photon emission computed tomography (SPECT) shows increased tracer uptake in acute herpes simplex viral encephalitis (HSVE). The purpose of this study was to evaluate the clinical usefulness of dynamic Tc‐ECD SPECT in patients with acute viral encephalitis.

METHOD

We performed the dynamic SPECT in 9 patients with acute viral encephalitis (4 women, 5 men, 49.5 ± 17.4 years of age at onset). SPECT and magnetic resonance imaging (MRI) were performed within 2 weeks after acute clinical onset and at the time of resolution of acute symptoms.

RESULTS

Cranial MRI showed high intensities in all patients (7 medial temporal and 2 lateral temporal lobes, 1 inferior temporal lobe, 2 insula and adjacent regions, 1 thalamus, 1 putamen). The initial dynamic SPECT showed increased accumulation of tracer, corresponding to the lesions on MRI in 3 patients with HSVE. Resolution of acute symptoms was associated with a reduction in increased tracer uptake. Six patients with non‐HSVE showed no increased accumulation of tracer.

CONCLUSIONS

Dynamic SPECT may be a new optional neuroradiologic technique that may help to establish a diagnosis in patients with suspected HSVE.
Reliability of fMRI during a Continuous Motor Task: Assessment of Analysis Techniques
Authors: Kimberley Teresa Jacobson , Birkholz Dana D. , Hancock Renee A. , VonBank Sarah M. , Werth Teresa N.
Published: October 2009

The purpose of this study was to determine which method of functional magnetic resonance image analysis had the highest reliability in cortical and cerebellar areas during a continuous motor task. Fourteen subjects underwent 4 testing trials during 2 testing sessions separated by 3 weeks. Subjects performed a joystick task. Methods of analysis evaluated included: percent signal intensity change, active voxel count, and percent contribution. Two types of activation thresholds were evaluated: P≤ .05 and false discovery rate = .05. Reliability was determined with intraclass correlation coefficients and a repeated measure ANOVA was used to determine whether there was a significant difference between trials. A group analysis was assessed with coefficient of variation. Results indicate within session reliability was higher than between session and that signal intensity is more reliable than voxel count analysis. The intraclass correlation coefficients across different regions of interest varied depending on analysis technique. The data did not support a clear difference between thresholds. The group analysis also found less variability with intensity measures than voxel count. A stabilization effect was seen after the first trial of the experiment, suggesting that in pretest/posttest designs, a more stable result may be obtained by performing a test trial prior to actual data collection.
Assessment of the Cerebral Vasomotor Reactivity in Internal Carotid Artery Occlusion Using a Transcranial Doppler Sonography and Functional MRI
Authors: Herzig Roman , Hluštík Petr , Školoudík David , Šaňák Daniel , Vlachová Ivanka , Heřman Miroslav , Kaňovský Petr
Published: October 2009

BACKGROUND AND PURPOSE

Several methods are being used to assess cerebral vasomotor reactivity (CVR), including transcranial Doppler (TCD) sonography and blood oxygenation level‐dependent functional magnetic resonance imaging (fMRI). The aim was to assess the correlation of TCD and fMRI in the CVR assessment.

METHODS

Study group consisted of 28 patients (24 males, 4 females; aged 30–82, mean 63.1 ± 10.0 years), presenting with 29 occluded internal carotid arteries. The TCD examination, including breath‐holding/hyperventilation test (BH/HV) and breath‐holding index (BHI), and fMRI examination were used for the assessment of CVR. fMRI employed a bimanual motor task within both a block paradigm and an event‐related paradigm. Cohen's κ was applied when statistically assessing correlation of the methods.

RESULTS

The following correlations were found—between BH/HV and BHI 58.6%, κ= .205; BH/HV and fMRI 65.5%, κ= .322; BHI and fMRI 58.6%, κ= .151; TCD (consistent result of both BH/HV and BHI test) and fMRI 70.6%, κ= .414.

CONCLUSIONS

In the evaluation of CVR, there is only a minimal correlation between the particular TCD tests (both BH/HV and BHI), and fMRI examination. However, there is a moderate correlation between TCD and fMRI in the case of congruity of both TCD tests.
Adult Idiopathic Occlusion of the Foramina of Monro: Diagnostic Tools and Therapy
Authors: De Bonis Pasquale , Anile Carmelo , Tamburrini Gianpiero , Tartaglione Tommaso , Mangiola Annunziato
Published: October 2009

BACKGROUND AND PURPOSE

The bilateral foramina of Monro occlusion is an extremely rare event in adults. To date, only six cases of adult hydrocephalus due to idiopatic obstruction of the bilateral foramina of Monro (including our patient) have been reported.

METHODS

The authors describe the case of a 41‐year‐old man with a recent onset of motor hindrance which occurred specially while jumping or playing basketball, together with recent memory impairment, deceleration of thought, and asthenia. The patient was studied with fast spin echo (FSE) and steady‐state free precession high‐resolution 3D sequences (SSFP) together with a ventricular infusion test, and subsequently treated with endoscopic foraminoplasty.

RESULTS

The presenting symptoms completely resolved. Follow‐up magnetic resonance imaging (MRI) showed the patency of right Monro foramen, with gradually decreasing ventricular size and increase of subarachnoid spaces.

CONCLUSIONS

These patients should be accurately studied before treatment. In fact, MRI has made it possible to know what a surgeon will exactly find on the operative field. In that way a correct surgical planning can be achieved.
Are Limb‐Shaking Transient Ischemic Attacks a Risk Factor for Postendarterectomy Hemorrhage? Case Report and Literature Review
Authors: Switzer Jeffrey A , Nichols Fenwick T
Published: October 2009

Postoperative intracerebral hemorrhage occurs in about 0.5% of all carotid endarterectomies. There are no recognized risk factors for this complication. We report on a 74‐year‐old woman with right sided limb‐shaking transient ischemic attacks and severe stenosis of the left internal carotid artery. She suffered a fatal intracerebral hemorrhage 11 days after endarterectomy. This case prompted a review of the literature to determine if limb‐shaking transient ischemic attacks might be a risk factor for postoperative intracerebral hemorrhage. We propose that patients with limb‐shaking transient ischemic attacks have loss of vasomotor reactivity placing them at high risk for carotid reperfusion syndrome and hemorrhage into the revascularized territory.
Prognostic Value of CT Angiography in Patients with Suspected Vertebrobasilar Ischemia
Authors: Sylaja P.N. , Puetz Volker , Dzialowski Imanuel , Krol Andrea , Hill Michael D. , Demchuk Andrew M.
Published: October 2009

BACKGROUND

The outcome of vertebrobasilar ischemia depends on the clinical presentation and the presence or absence of vascular occlusion. The aim of our study was to analyze the CT angiography (CTA) predictors of outcome in patients with suspected vertebrobasilar ischemia.

METHODS

We studied patients with suspected acute vertebrobasilar ischemia between April 2002 and January 2006 and had CTA done within 24 hours of symptom onset. We reviewed the final diagnosis and 3‐month follow‐up and analyzed the clinical and CTA predictors of outcome.

RESULTS

Of the 133 patients, 21(15%), 18 (13%), and 16 (12%) had occlusion of basilar artery (BA), vertebral artery (VA), and posterior cerebral artery (PCA) respectively. The final diagnosis was stroke in 98 (73.6%), transient ischemic attack (TIA) in 10 (7.5%), and nonischemic in 25 (18.8%). No vascular occlusion was seen on CTA in patients with TIA and nonischemic diagnosis. At 3‐month follow‐up, we found a mortality rate of 10.6% and good functional outcome in 71.4%. The predictors of death in the multivariable analysis were the presence of BA occlusion (odds ratio[OR] 6.7, 95% CI, 1.4–30.6) and baseline National Institutes of Health Stroke Scale (NIHSS) (OR 1.14, 95% CI, 1.06–1.2). When patients with basilar occlusion were excluded, the presence of VA occlusion (OR 6.5, 95% CI, 1.34–31.4), age (OR 1.09, 95% CI, 1.03–1.14), and baseline NIHSS (OR 1.1, 95% CI, 1.03–1.18) predicted poorer outcome.

CONCLUSIONS

The presence or absence of a vascular occlusion is a critical factor for prognosis in suspected acute vertebrobasilar ischemia and is correlated with the location of occlusion.
In Vivo Visualization of Senile‐Plaque‐Like Pathology in Alzheimer's Disease Patients by MR Microscopy on a 7T System
Authors: Nakada Tsutomu , Matsuzawa Hitoshi , Igarashi Hironaka , Fujii Yukihiko , Kwee Ingrid L.
Published: October 2009

BACKGROUND

Microscopic application of magnetic resonance imaging (MRI) has entered the era of clinical application. One of the most important targets is the visualization of pathological findings such as senile plaques (SP), in vivo, in patients with Alzheimer's disease (AD). Such an application provides not only the most accurate diagnostic tool for clinicians but also a solid basis for scientists for developing effective treatment and preventive strategies for AD.

METHODS

Focused microscopic studies were performed on parietal association cortex at the level of the centrum semiovale identified on conventional axial slices using a system constructed based on General Electric Signa LX (Waukesha, WI) equipped with a 900‐mm clear bore superconducting magnet operating at 7.0 T in 10 patients (67‐83‐year old, five males, five females) who fulfilled the NINCD and the SADRDA criteria for probable AD, 10 age‐matched controls (71‐85‐year old, five males, five females), and 20 young adults (22‐35‐year old, 10 males, 10 females) using a susceptibility weighted imaging (SWI) algorithm.

RESULTS

SWI microscopy consistently provided images with SP‐like pathology extending within the entire parietal cortex in all cases of AD and 2 out of 10 age‐matched volunteers.

CONCLUSIONS

Although the precise mechanisms leading to the higher susceptibility rendering SP‐like pathology observable within the cortical mantle are not totally understood, the study unambiguously demonstrated that MR microscopy is capable of directly visualizing cortical pathology in AD patients in vivo.
CSF Rhinorrhea from a Transclival Meningocele: A Case Report
Authors: Akyuz Mahmut , Arslan Gokhan , Gurkanlar Doga , Tuncer Recai
Published: October 2009

The most common site of cerebrospinal fluid (CSF) leakage is through the floor of the anterior fossa, which communicates with the ethmoid or frontal sinuses or with the nasal fossa. The sphenoid sinus is rarely implicated as a source of spontaneous CSF fistula. Transclival meningocele is an extremely rare lesion. A 36‐year‐old woman with a 1‐year history of intermittent CSF rhinorrhea was found to have a transclival meningocele. The diagnosis of transclival meningocele was made by magnetic resonance (MR), 3‐dimension‐computerized tomography (CT). At operation, by a transsphenoidal approach, the transclival meningocele was packed with fasia lata graft, fat tissue, and bio‐glue. This is the third case of transsphenoidal transclival meningocele producing rhinorrhea in an adult. Transclival meningocele should be taken into consideration in patients with spontaneous CSF rhinorrhea.
Atypical Wernicke's Encephalopathy Showing Lesions In the Cranial Nerve Nuclei and Cerebellum
Authors: Zuccoli Giulio , Motti Luisa
Published: October 2009

Wernicke's encephalopathy (WE) is a severe neurological disorder caused by a dietary deficiency of Vitamin  B1 and characterized by consciousness changes, ocular abnormalities, and ataxia. Wernicke's encephalopathy is considered a medical emergency and treatment consists of intravenous thiamine administration. Typically in alcoholic and nonalcoholic patients magnetic resonance shows alterations in the mamillary bodies, medial thalami, tectal plate, and periaqueductal regions. We report here on a nonalcoholic atypical case of WE which presented with reversible symmetrical lesions in the cranial nerves nuclei and in the cerebellum alongside the classic neuroradiological findings.
Validation of Two Different Grading Schemes to Identify Patients With Asymptomatic Carotid Artery Stenosis in General Population
Authors: Suri M. Fareed K. , Ezzeddine Mustapha A. , Lakshminarayan Kamakshi , Divani Afshin A. , Qureshi Adnan I.
Published: October 2009

BACKGROUND

Identification of significant asymptomatic carotid artery stenosis (ACAS) is important because of potential stroke‐risk reduction offered by carotid endarterectomy. We present an external validation of two previously developed scoring schemes designed to identify patients with ACAS.

METHODS

We used the data from the Cardiovascular Health Study (CHS)—a cohort study of cardiovascular risk factors, for external validation. Carotid Doppler ultrasound was performed in study participants. Two grading schemes, which used age more than 65 years, current smoking, and history of coronary artery disease and hyperlipidemia as predictors for ACAS, were validated using this dataset.

RESULTS

A total of 5,449 persons (mean age 72 ± 5 years; 42% men; and 84% white) were screened. The overall prevalence of ACAS of ≥50% was 4.2%. The prevalence of ACAS in the highest risk category was 19% in both stratification schemes. The stratification remained effective in the white sub‐population (P < .001), but was not significant in the African American population (P > .05).

CONCLUSION

Both schemes were effective in identifying persons with ACAS among general population aged 65 years or greater. A subset with a prevalence of ACAS of greater than 20% can be identified using these schemes making screening cost‐effective among white population.
In Vivo Imaging of Neurotransmission and Brain Receptors in Dementia
Authors: Pappatà Sabina , Salvatore Elena , Postiglione Alfredo
Published: October 2009

Positron emission tomography (PET) and single photon emission tomography (SPECT) are the most sensitive techniques to study, in vivo, neurotransmitter systems in normal human brain and in diseases. These methods have been applied over the last years to explore the integrity of cholinergic, serotonergic, GABAergic, and dopaminergic systems in Alzheimer's disease (AD) and in other dementias. The results of these investigations have provided new insights into the neurotransmission involvement in these disorders. Moreover, these methods provide objective quantitative markers for monitoring the progression of disease and the effects of therapies. The pathophysiological and clinical relevance of results from these studies are reviewed and the potential role in early and differential diagnosis discussed. New emerging radiotracers/methods for future investigations of neurochemical processes are delineated.
Multi‐Site Phasic Neural Activity Mediates the Execution of An Auditory Continuous Performance Task: A PET and Electrophysiological Study
Authors: Lockwood Alan H. , Wack David S. , Benedict Ralph H. B. , Coad Mary Lou , Sussman Joan E. , Burkard Robert F.
Published: October 2009

BACKGROUND AND PURPOSE

We studied an auditory continuous performance task with positron emission tomography (PET) and EEG‐derived current density reconstructions (CDRs) to define the spatial and temporal aspects of auditory attention.

METHODS

The CDRs were employed to segregate responses to targets and non‐targets at sites identified by PET. We then studied the time course of brain activity using statistical parametric mapping (SPM) of the CDR data.

RESULTS

In contrast to target EEG activity, non‐targets did not produce significant peaks after 300 ms. Pre‐300 ms biphasic activation of auditory, left posterior frontal, left supplemental, and primary motor cortices and the anterior cingulate (AC) and biphasic suppression of posterior cingulate and occipital cortex were identical for targets and non‐targets and may mediate the target non‐target decision. SPM analysis of post‐300 ms CDRs showed cingulate cortices were the first to be reactivated, remained active through 672 ms, and were accompanied by reactivation and deactivation of the same sites observed in the pre‐P300 responses.

CONCLUSIONS

The cingulate may play an important role in post‐decisional activity and control activity at other sites involved in post‐decisional cognitive processing.
Regional Specificity of Magnetization Transfer Imaging in Multiple Sclerosis
Authors: Tjoa Christopher W. , Benedict Ralph H. B. , Dwyer Michael G. , Carone Dominic A. , Zivadinov Robert
Published: October 2009

BACKGROUND

The goal of this study was to develop and validate a method for generation of regional magnetization transfer ratio (MTR). We also studied the topography of MTR changes in multiple sclerosis (MS) and in normal controls (NC), and preliminarily examined the clinical usefulness of this method.

METHODS

We examined 45 patients with MS (relapsing remitting [RR]= 28 and secondary progressive [SP]= 17] and 19 NC. Mean disease duration was 14.3 years and median Expanded Disability Status Scale was 3.0. Regions of the brain were determined using semiautomated brain region extraction (SABRE). Twenty‐six regional masks were automatically applied to MTR maps that were further split into gray matter (GM) and white matter (WM) compartments.

RESULTS

Mean MTR from 12 SABRE regions differed significantly between MS patients and NC. For WM, all regional mean MTRs differed significantly between RR, SP, and NC participants (P < .001). In regression analysis, only 3 regions remained significantly different when corrected for total T2‐LV. The regression model predicting disability selected GM mean MTR of the right medial inferior frontal region (P= .031).

CONCLUSIONS

The study results showed that this regional MTR approach is reproducible, reliable and clinically relevant. MTI changes occur selectively in specific sub‐regions.
Proton Magnetic Resonance Spectroscopy Detects a Relative Decrease of N‐Acetylaspartate in the Hippocampus of Patients With Dementia With Lewy Bodies
Authors: Xuan Xiaqing , Ding Meiping , Gong Xiangyang
Published: October 2009

BACKGROUND AND PURPOSE

To characterize the cerebral metabolic changes in dementia with Lewy bodies patients.

METHODS

The metabolic ratios of NAA/Cr and Cho/Cr in bilateral hippocampus were determined by proton magnetic resonance spectroscopy in 8 patients and 8 age‐matched healthy controls.

RESULTS

Dementia with Lewy bodies patients showed significantly lower NAA/Cr ratios in bilateral hippocampus, while the Cho/Cr ratio did not differ from the control group.

CONCLUSIONS

Our data show relatively decrease of N‐acetylaspartate in the hippocampus of patients with early or intermediate stage DLB. Hence, damage of neurons seems to be an early alteration in DLB.
Lactate Detection by MRS in Mitochondrial Encephalopathy: Optimization of Technical Parameters
Authors: José da Rocha Antônio , Túlio Braga Flávio , Carlos Martins Maia Júnior Antonio , Jorge da Silva Carlos , Toyama Carlos , Pereira Pinto Gama Hugo , Kok Fernando , Rodrigues Gomes Hélio
Published: October 2009

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

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

BACKGROUND

In Sturge‐Weber syndrome (SWS), structural MRI abnormalities are most common in the posterior brain regions. Frontal lobe involvement increases the risk of motor impairment. The goal of this study was to determine whether Magnetic Resonance Spectroscopic Imaging (MRSI) can improve detection of frontal lobe involvement in children with SWS.

METHODS

Sixteen children (age: .9‐10.4 years) with unilateral SWS underwent MRI with MRSI prospectively. N‐acetyl‐aspartate (NAA) and choline asymmetries in the posterior and frontal regions were measured.

RESULTS

Eight children presented normal‐appearing frontal lobes on conventional MRI, but 7 of them showed abnormal NAA and/or choline content in the frontal lobe of the affected hemisphere. Lower frontal lobe gray matter NAA was associated with earlier onset of seizures (r= .76; P= .04) and impaired motor function (r=−.89, P < .001). Frontal NAA asymmetry was an independent predictor of motor function in a regression analysis (P= .01)

CONCLUSION

MRSI is more sensitive than conventional structural MRI for detection of frontal lobe involvement in SWS. Decreased frontal lobe NAA is an excellent predictor of motor functions. Thus, MRSI can provide complementary information for the assessment of normal‐appearing brain regions, and may assist prognosis evaluation in children with SWS.
Angiographic Demarcation of an Occlusive Lesion May Predict Recanalization after Intra‐arterial Thrombolysis in Patients with Acute Middle Cerebral Artery Occlusion
Authors: Otsuka Yoshinobu , Waki Riichiro , Yamauchi Hiroshi , Fukazawa Seiji , Kimura Kaku , Shimizu Kotoyuki , Fukuyama Hidenao
Published: October 2009

BACKGROUND AND PURPOSE

The aim of this study is to investigate whether angiographic demarcation of an occlusive lesion may predict successful or failed result of intra‐arterial thrombolysis in acute middle cerebral artery (MCA) occlusion.

METHODS

We reviewed retrospectively the angiography and clinical data of acute MCA occlusion patients who underwent intra‐arterial thrombolysis from 1994 to 2004. Pretreatment angiographic findings at the occlusive lesions were classified as either blurred or sharp, depending on whether the proximal portion of the occlusive lesions had poorly or well demarcated margins. Using uni‐ or multivariate analysis, recanalization was correlated with our angiographic classification or other clinical variables.

RESULTS

Forty‐six patients with MCA occlusions underwent intra‐arterial thrombolysis during the 10‐year period. Forty‐four of the angiograms could be classified into one of the two categories: Blurred‐type in 20 patients and Sharp‐type in 24 patients. Univariate analysis showed a significant association of the classification with recanalization. (Recanalization rate: 95% in Blurred‐type and 38% in Sharp‐type, P < .0001) Logistic regression analysis showed that the association was independent from other factors (P= .004).

CONCLUSION

In acute MCA occlusion, our classification may indicate the difficulty of the recanalization procedure, and may assist in patient triage for different intra‐arterial treatment strategies.
Qualification Requirements for Performing Neurointerventional Procedures: A Report of the Practice Guidelines Committee of the American Society of Neuroimaging and the Society of Vascular and Interventional Neurology
Authors: Qureshi Adnan I. , Abou‐Chebl Alex , Jovin Tudor G.
Published: October 2009

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

BACKGROUND

Ischemic stroke is mainly caused by embolism. Vascular emboli can be solid or gaseous and can be non‐invasively registered by transcranial Doppler ultrasound as microembolic signals (MESs). The existing methods are limited as they do not distinguish between cases in which a single embolus is present and those in which multiple emboli—perhaps a mix of those gaseous and solid in nature—are present. In a previous in vitro study, we have developed a wavelet‐based algorithm to detect multiple emboli. We proceed with this technique to investigate whether it could prove useful in patients.

METHOD

MESs were collected during emboli monitoring from patients undergoing carotid artery stenting and from patients having middle cerebral artery stenosis, and continuous wavelet transform was used to detect multiple emboli.

RESULTS

From 17 MESs recorded from middle cerebral artery stenosis patients, we found no multiple MES. From 306 MESs recorded from carotid stenting, we found 31 multiple MESs.

CONCLUSION

Multiple emboli were detected and quantified in patients using continuous wavelet transform. These were difficult to observe using conventional analysis techniques.
Hypertensive Encephalopathy Presenting with Isolated Brain Stem and Cerebellar Edema
Authors: Bhagavati Satyakam , Chum Florence , Choi Jai
Published: October 2009

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

BACKGROUND AND PURPOSE

While sensitive to internal carotid artery (ICA) occlusion, carotid ultrasound can produce false‐positive results. CT angiography (CTA) has a high specificity for ICA occlusion and is safer and cheaper than catheter angiography, although less accurate. We determined the cost‐effectiveness of CTA versus catheter angiography for confirming an ICA occlusion first suggested by carotid ultrasound.

METHODS

A Markov decision‐analytic model was constructed to estimate the cost‐effectiveness of CTA compared with catheter angiography in a hypothetical cohort of symptomatic patients with a screening examination consistent with an ICA occlusion. Costs in 2004 dollars were estimated from Medicare reimbursement. Effectiveness was measured in quality‐adjusted life years.

RESULTS

The 2‐year cost in the CTA scenario was $9,178, and for catheter angiography, $11,531, consistent with a $2,353 cost‐savings per person for CTA. CTA resulted in accrual of 1.83 quality‐adjusted life years while catheter angiography resulted in 1.82 quality‐adjusted life years. CTA was less costly and marginally more effective than catheter angiography. In sensitivity analyses, when CTA sensitivity and specificity were allowed to vary across a plausible range, CTA remained cost‐effective.

CONCLUSIONS

After screening examination has suggested an ICA occlusion, confirmatory testing with CTA provides similar effectiveness to catheter angiography and is less costly.
Detection of Right‐to‐Left Shunts: Comparison between the International Consensus and Spencer Logarithmic Scale Criteria
Authors: Lao Annabelle Y. , Sharma Vijay K. , Tsivgoulis Georgios , Frey James L. , Malkoff Marc D. , Navarro Jose C. , Alexandrov Andrei V.
Published: October 2009

BACKGROUND

International Consensus Criteria (ICC) consider right‐to‐left shunt (RLS) present when Transcranial Doppler (TCD) detects even one microbubble (μB). Spencer Logarithmic Scale (SLS) offers more grades of RLS with detection of >30 μB corresponding to a large shunt. We compared the yield of ICC and SLS in detection and quantification of a large RLS.

SUBJECTS AND METHODS

We prospectively evaluated paradoxical embolism in consecutive patients with ischemic strokes or transient ischemic attack (TIA) using injections of 9 cc saline agitated with 1 cc of air. Results were classified according to ICC [negative (no μB), grade I (1‐20 μB), grade II (>20 μB or “shower” appearance of μB), and grade III (“curtain” appearance of μB)] and SLS criteria [negative (no μB), grade I (1‐10 μB), grade II (11‐30 μB), grade III (31100 μB), grade IV (101300 μB), grade V (>300 μB)]. The RLS size was defined as large (>4 mm) using diameter measurement of the septal defects on transesophageal echocardiography (TEE).

RESULTS

TCD comparison to TEE showed 24 true positive, 48 true negative, 4 false positive, and 2 false negative cases (sensitivity 92.3%, specificity 92.3%, positive predictive value (PPV) 85.7%, negative predictive value (NPV) 96%, and accuracy 92.3%) for any RLS presence. Both ICC and SLS were 100% sensitive for detection of large RLS. ICC and SLS criteria yielded a false positive rate of 24.4% and 7.7%, respectively when compared to TEE.

CONCLUSIONS

Although both grading scales provide agreement as to any shunt presence, using the Spencer Scale grade III or higher can decrease by one‐half the number of false positive TCD diagnoses to predict large RLS on TEE.
Novel Applications of Magnetic Resonance Imaging to Image Tissue Inflammation after Stroke
Authors: Nighoghossian Norbert , Wiart Marlene , Berthezene Yves
Published: October 2009

Experimental studies suggest that stroke‐induced brain damage progresses during subacute stages. Cerebral ischemic injury is associated with the induction of a series of inflammatory events, including the infiltration of circulating immune cells and activation of resident cells. Local brain inflammation is spatiotemporally related to the occurrence of delayed apoptotic cell death. Therefore, ischemia‐associated inflammation may not only play a major role in the pathogenesis of neurodegeneration associated with stroke, but may also mediate beneficial effects such as lesion demarcation, wound healing, and tissue regeneration especially via secretion of nerve growth factors. In this context, noninvasive imaging of inflammation associated with ischemic stroke lesions could have a predictive value and may be helpful for the development of cytoprotective drugs.