bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Gadolinium Enhancement Predictive of the Development of Brain Atrophy in Multiple Sclerosis? A Review of the Literature
Authors: Zivadinov Robert , Zorzon Marino
Published: November 2009

Background and Purpose. Several studies have demonstrated that brain atrophy can be detected over relatively short intervals from the earliest stages of multiple sclerosis (MS). Reviewing the published data, the authors highlight some hypothetical pathological mechanisms proposed as determinants of brain atrophy. Methods. Using the terms multiple sclerosis, MRI (magnetic resonance imaging), and brain atrophy, 181 citations were identified. The authors considered only studies with prospective designs with natural‐course MS patients and/or placebo‐treated patients of therapeutic trials, in which patients under‐went baseline and follow‐up scans with a T1‐weighted gadolinium diethylenetriamine penta‐acetic acid sequence (0.1 mmol/kg body weight), and correlation analyses between Gd enhancement activity and brain atrophy progression. Results. Five hundred thirty‐two patients of 5 natural history studies and 5 therapeutic trial studies participated in the review process. The main observation was that in patients with a relapsing‐remitting (RR) disease course, there was a correlation between Gd enhancement activity and brain atrophy progression. This correlation was not influenced by any other demographic and clinical additional data considered in the review process. Conclusions. Examination of the pathological mechanisms pro‐posed in the reviewed studies led the authors to believe that inflammation is only in part responsible for the development of brain atrophy. This conclusion may have an implication for the strategies of tissue protection advocated in the early stages of the RR course and strengthen recent evidence indicating that anti‐inflammatory immunomodulatory agents and immunosuppressive treatments, which predominantly act against the inflammatory component of disease activity, may not have similar effects on progressive tissue loss, either in RR or progressive MS.
Blood Flow Velocities in the Basal Cerebral Vein After Head Trauma: A Prospective Study in 82 Patients
Authors: Mursch Kay , Müller Christian‐Andreas , Buhre Wolfgang , Lang Johannes K. , Vatter Hartmut , Behnke‐Mursch Julianne
Published: November 2009

Background and Purpose. The authors' aim was to evaluate the time course of the basal vein's (BVR) mean flow velocity (VBVR)in patients after traumatic brain injury and its relation to intracranial pressure (ICP), cerebral perfusion pressure (CPP), and the clinical outcome. Methods. In 82 head‐injured patients (13 women and 69 men, median age = 31 years, Glasgow Coma Score = 15 to 3), daily measurement of the basal cerebral vein's and the middle cerebral artery's (MCA) flow velocities and pulsatilities was performed during each patient's entire stay in the intensive care unit. No angle correction was performed. A computerized sonography system (SD 800, Philips, Irvine, CA) with a 2.0‐MHz to 2.5‐MHz transducer was used for all measurements. The Glasgow Outcome Score (GOS) was evaluated after 6 months. Results. During the study period, VBVR values on the side of trauma were higher in the patients with favorable outcomes (GOS = 4 and 5) compared to patients with unfavorable out‐comes (GOS = 2 and 3). This was statistically significant on days 4, 6, 7, and 11 and was not observed in the mean flow velocity of the MCA (VMCA). VBVR values among the good‐outcome group tended to exceed the normal mean flow velocity (9.1 cm/s), whereas the unfavorable‐outcome group was below this level. A correlation between venous flow velocity or pulsatility and ICP or CPP was not observed. Conclusions. Repetitive Doppler examination of the basal cerebral veins may add new aspects to the monitoring of head‐injured patients.
A Case Study of Hemispatial Neglect Using Finite Element Analysis and Positron Emission Tomography
Authors: Peña Alonso , Owler Brian K. , Fryer Tim D. , Minhas Pawan , Czosnyka Marek , Crawford Peter J. , Pickard John D.
Published: November 2009

Background. The authors present a patient who developed transient hemispatial neglect following surgical drainage of a large right frontotemporal arachnoid cyst. As symptoms evolved in parallel with brain shift over the subsequent months, the authors hypothesized that the disorder was associated with the appearance of mechanical stresses in the cerebral mantle. Methods. To map tissue stress at the various stages of deformation, a finite element computer simulation was conducted on the basis of computed tomography scans of the patient. Results. The authors' results demonstrate substantial shear and compressive stress concentrations in the parietal lobe, a region commonly associated with neglect, and where positron emission tomography confirmed hypoperfusion in this patient. Treatment with combined ventricular‐peritoneal and cystoperitoneal shunts was accompanied by clinical recovery and improvement of right parietal lobe cerebral blood flow. Conclusions. The authors conclude that brain deformation was a contributing factor in the reversible neglect syndrome by compromising the normal flow of blood and/or the deactivation of subcortical circuits of the parietal lobe.
Development of a Posterior Fossa Cavernous Malformation Associated With Bilateral Venous Anomalies: Case Report
Authors: Sheehan Jason , Lunsford L. Dade , Kondziolka Douglas , Flickinger John
Published: November 2009

Venous angiomas (VAs) and cavernous malformations (CMs) are common cerebrovascular malformations. Frequently, these lesions are found in close proximity. The interrelationship between VAs and CMs has not yet been adequately defined. The authors report a case of a 48‐year‐old man with progressive dysarthria, dysmetria, and ataxia. Eight years previously, magnetic resonance imaging (MRI) revealed a solitary CM and bilateral posterior fossa VAs. Later imaging after neurological progression revealed the presence of 2 rather than 1 CMadjacent to the VAs. The sequential imaging suggests a causal relationship between VAs and some CMs. Furthermore, the detailed MRI permitted radiosurgical treatment of these CMs. The occurrence of de novo CMs adjacent to VAs on future imaging studies in other patients may help confirm the etiology of at least a subset of CMs.
Approach to Imaging the Patient With Neck Pain
Authors: Tong Carrie , Barest Glenn
Published: November 2009

Neck pain is a common complaint of patients seeking care in the outpatient setting, and the cases seen vary widely in severity and cause. A careful history and physical exam, followed by appropriate imaging studies, are essential for the orderly workup and management of neck pain in the ambulatory patient. Available imaging studies include plain film radiography, computed tomography (CT), magnetic resonance, and CT myelography. The general considerations necessary to select the appropriate imaging study are discussed for a broad spectrum of common disorders.
Residual Flow Signals Predict Complete Recanalization in Stroke Patients Treated With TPA
Authors: Labiche Lise A. , Malkoff Marc , Alexandrov Andrei V.
Published: November 2009

Background. Residual blood flow around thrombus prior to treatment predicts success of coronary thrombolysis. The authors aimed to correlate the presence of residual flow signals in the middle cerebral artery (MCA) with completeness of recanalization after intravenous tissue plasminogen activator (TPA). Methods. The authors studied consecutive patients treated with intravenous TPA therapy who had a proximal MCA occlusion on pretreatment transcranial Doppler (TCD). Patients were continuously monitored for 2 hours after TPA bolus. Absent residual flow signals correspond to the thrombolysis in brain ischemia (TIBI) 0 grade, and the presence of residual flow signals was determined as TIBI 1‐3 flow grades. Complete recanalization was defined as flow improvement to TIBI grades 4‐5. Results. Seventy‐five patients with a proximal MCA occlusion had median pre‐bolus NIHSS 16 (85% with ≥10 points). TPA bolus was given at 141 ± 56 minutes (median 120 minutes). Complete recanalization was observed in 25 (33%), partial in 23 (31%), and no early recanalization was seen in 27 (36%) patients within 2 hours after TPA bolus. Only 19% with absent residual flow signals (TIBI grade 0, n= 26) on pretreatment TCD had complete early recanalization. If pretreatment TCD showed the presence of any residual flow (TIBI 1‐3, n= 49), 41% had complete recanalization within 2 hours of TPA bolus (P = .03). Conclusions. Patients with detectable residual flow signals before IV TPA bolus are twice as likely to have early complete recanalization. Those with no detectable residual flow signals have less than 20% chance for complete early recanalization with intravenous TPA and may be candidates for intra‐arterial therapies.
Neurovascular Coupling Remains Unaffected During Normal Aging
Authors: Rosengarten B. , Aldinger C. , Spiller A. , Kaps M.
Published: November 2009

Background and Purpose. During normal aging, the cerebral autoregulation mechanism and the CO2‐induced cerebral reserve capacity remain unaffected. This led to the suggestion of a wide compensatory range of mechanisms responsible for the cerebral blood flow regulation. The authors investigated the neurovascular coupling mechanism for age‐related changes. Because several authors criticized the comparison between higher and younger age groups, the current authors restricted their study on volunteers between 10 and 60 years. Methods. Twenty healthy volunteers in the age group of 10 to 20, 20 to 40, and 40 to 60 each without cerebrovascular risk factors were enrolled in this study; they were aged 16.3 ± 3.4 SD years (9 boys), 32.7 ± 2.3 SD years (9 men), and 53.1 ± 5.3 SD years (10 men). A functional transcranial Doppler test was performed using a visual stimulation paradigm. The resultant flow velocity changes in the posterior cerebral artery were analyzed using a control system approach. Resting flow velocity and each of the control system parameters, which were time delay, attenuation, natural frequency, rate time, and gain, were compared between groups statistically. Results. Control system parameters remained statistically unchanged between groups, whereas the resting flow velocity decreased significantly by age. Conclusions. The neurovascular coupling mechanism seems to be unaffected by moderate aging as estimated by Doppler parameters. Vasoregulative dysfunction in patients at vascular risk is more likely to be caused by the risk factor rather than by age.
The Role of Transcranial Doppler in Symptomatic Striatocapsular Small Deep Infarction
Authors: Bang Oh Young , Joo In Soo , Huh Kyoon , Kim Sun Yong
Published: November 2009

Background and Purpose. The transcranial Doppler (TCD) findings in symptomatic small deep infarction are not well known. The aim of this study was to evaluate the role of TCD in striatocapsular small deep infarctions (SSDIs). Methods. The cerebral angiography and TCD findings were analyzed on 100 patients with symptomatic cerebral infarcts on the middle cerebral artery (MCA) territory. The sensitivity, specificity, and accuracy of TCD in detecting the MCA lesions were compared between lacunar group (the patients with lacunar syndrome and SSDIs on magnetic resonance image) and nonlacunar group. Results. Thirty‐eight patients were classified as the lacunar group, whereas 62 patients as the nonlacunar group. On angiography, occlusive lesion of MCA was found in 18 of the lacunar group and 24 patients of the nonlacunar group. The degree of MCA stenosis was higher in the nonlacunar group (80.8%± 21.2%) than the lacunar group (60.4%± 21.6%). The accuracy of TCD for the detection of MCA stenosis was not different between the groups. However, the sensitivity of TCD in the lacunar group was lower (72%) than in the nonlacunar group (88%), and it might have been due to the difference in the degree of MCA stenosis among the groups. Conclusions. Occlusive lesions of the MCA should be considered as a potential cause of SSDIs. In this respect, TCD may be used for screening candidates for conventional angiography in those patients. High rate of mild‐degree stenosis of MCA in patients with SSDIs, however, caused a risk for missing such stenosis on TCD.
Outcome in Children With Significantly Abnormal Cerebral Blood Flow Detected by Doppler Ultrasonography: Focus on the Survivors
Authors: Chiu Nan‐Chang , Shen Ein‐Yiao , Ho Che‐Sheng
Published: November 2009

Background and Purpose. The Doppler waveform patterns of loss of diastolic flow, appearance of retrograde diastolic flow, or no detectable flow in the cerebral arteries suggest significantly abnormal cerebral blood flow (CBF). A retrospective study was performed to show that significantly abnormal CBF alone, without clinical criteria, is not necessarily specific to brain death in the young pediatric population. Patients and Methods. Forty‐seven pediatric patients, from newborn to 4 years of age, were found to have significantly abnormal CBF, including 7 patients with loss of diastolic flow, 28 with retrograde diastolic flow, and 23 with no detectable cerebral flow on serial Doppler sonographic examinations. Their clinical data and sonographic results were collected and analyzed. Results. Forty‐two patients died, a few of whom had only transient improvement of cerebral flow. All of the patients with no detectable cerebral flow expired. Five patients survived with or without sequelae. Their underlying conditions that caused increased intracranial pressure were treated by medical and/or surgical intervention, and diastolic reversal of CBF corrected within 1 day in all 5. Conclusions. Although no detectable flow is a lethal sign, pediatric patients with loss or reversal of diastolic flow may survive with prompt and effective treatment. Using Doppler ultrasound to diagnose cerebral circulatory arrest should be done with caution in pediatric patients.
MRI Findings of Hemolytic Uremic Syndrome With Encephalopathy: Widespread Symmetrical Distribution
Authors: Nakamura Hiroshi , Takaba Hitonori , Inoue Takeshi , Saku Yoshisuke , Saito Fumihiko , Ibayashi Setsuro , Fujishima Masatoshi
Published: November 2009

The authors report the magnetic resonance imaging (MRI) findings in a 22‐year‐old woman with hemolytic uremic syndrome and encephalopathy secondary to verotoxin‐producing Escherichia coli. Multiple lesions in the midbrain, cerebellum, occipital lobe, and basal ganglia showed high signal intensity on T2‐weighted images with widespread symmetrical distribution. Most of these findings showed remarkable reduction on MRI images obtained 70 days after the onset. It is suggested that edema induced by local breakdown of blood‐brain barrier might play an important role in the patient.
Trancranial Doppler Monitoring of Response to Therapy for Meningovascular Syphilis
Authors: Kelley Roger E. , Minagar Alireza , Kelley Bradford J. , Brunson Regina
Published: November 2009

Meningovascular syphilis is now quite uncommon, but there have been increasing reports in patients immunocompromised with human immunodeficiency virus. The response of syphilis affecting the central nervous system to antibiotic therapy remains a challenge. This is an even greater challenge in patients who have underlying compromise of the immune system. The authors present a 46‐year‐old male with recurrent stroke who was found to have cerebrospinal fluid compatible with syphilitic involvement of the central nervous system and a cerebral arteriogram, which revealed focal narrowing of the right middle cerebral artery. The baseline transcranial Doppler study demonstrated increased mean and peak flow velocity within the right middle cerebral artery. Despite a 10‐day course of intravenous penicillin, with substantial improvement in the cerebrospinal fluid results, this flow velocity elevation persisted, in a remarkably consistent pattern, over a 4‐month follow‐up period. Thus, the involved vessel remained patent following treatment, but no clear resolution of the stenotic lesion was observed.
B0 Images Obtained From Diffusion‐Weighted Echo Planar Sequences for the Detection of Intracerebral Bleeds
Authors: Lam WWM , So NMC , Wong KS , Rainer T
Published: November 2009

Background and Purpose. To evaluate the accuracy of B0 echo planar imaging (EPI) sequences for the detection of intracerebral bleeds. Methods. One hundred patients with acute strokes had magnetic resonance imaging and computed tomography (CT) examinations performed within 48 hours after the onset of symptoms. The detectability of intracerebral bleeds by the B0 EPI sequences was assessed. The results were compared to the gradient echo (GRE) sequence and CT brain examinations. The results of the GRE sequences were used as the gold standard. Results. The B0 EPI sequences detected 11 out of 11 acute, intracerebral hematomas; 6 out of 8 acute hemorrhagic strokes; 2 out of 2 acute, intraventricular hemorrhages; 8 out of 8 old hemorrhagic infarcts; 1 out of 1 subarachnoid hemorrhages; and 11 out of 22 patients with microbleeds. For the detection of acute, intracerebral hematomas and acute, hemorrhagic infarcts, B0 EPI sequences had a sensitivity of 89.5%, a specificity of 100%, and an accuracy of 98%. CT had a sensitivity of 57.9%, a specificity of 100%, and an accuracy of 92%. B0 EPI sequences did not miss any acute or chronic hemorrhages detected by CT examinations. Conclusions. B0 EPI sequences could not replace GRE images for the detection of both acute and chronic hemorrhages. Their sensitivity for the detection of acute and chronic blood products, however, was comparable, if not superior, to that of CT examinations.
Characteristics of Microembolic Signals Detected Near Their Origins in Middle Cerebral Artery Stenoses
Authors: Gao Shan , Wong Ka Sing
Published: November 2009

Background and Purpose. Usually, microembolic signal (MES) monitoring is performed for MESs arising from downstream sources. The aim of this study is to describe the special characteristics of MESs originating from nearby sources in the middle cerebral artery (MCA). Methods. We analyzed 265 MESs detected in 5 patients (the study group) who had acute ischemic strokes within the territory of MCA stenoses and 48 MESs detected in 7 patients (the control group) from proximal sources: severe internal carotid artery stenoses and prosthetic heart valves. MESs were recorded with a 2‐MHz, bigate transducer. We performed offline analyses of the recorded MESs using both post–fast Fourier transform (FFT) spectra and pre‐FFT time domain signals. MESs were divided into 3 types–focused frequency signals (FFSs), bottom‐frequency signals (BFSs), and multifrequency signals (MFSs)–according to the frequencies of the signals displayed on the post‐FFT spectra. Results. In the study group, among 265 MESs, 245 (92.5%) were MFSs, 11 (4.2%) were FFSs, and 9 (3.4%) were BFSs. In the control group, among 48 MESs, 45 (93.5%) were FFSs, 2 (4.2%) were MFSs, and 1 (2.%) was a BFS. There was significant difference in MES type between MCA stenoses and other embolic sources (P < .05). On the post‐FFT spectra, MFSs recorded from MCA stenoses occupied multiple frequencies along the vertical axis, and the low‐frequency parts were usually bidirectional. On the pre‐FFT time domain signals, the highest frequency parts presented distorted, amplitude‐modulated sine waves, and the low‐frequency parts presented totally irregular waves. The amplitudes of the low‐frequency parts diminished with time in the proximal channel but enlarged with time in the distal channel over a short period. Conclusion. MESs recorded from MCA stenoses may have special characteristics of multiple frequencies on both post‐FFT spectra and pre‐FFT time domain signals. Our findings may represent rotating or vibrating emboli as they are just dislodged from the thrombus and are moving from the vessel wall to the center. Further clinical and laboratory studies are needed to confirm this hypothesis.
Measurement of Carotid Stenosis: Comparisons Between Duplex and Different Angiographic Grading Methods
Authors: Hwang Chi‐Shin , Liao Kuo‐Meng , Lee Jun‐Hong , Tegeler Charles H.
Published: November 2009

Background and Purpose. Endarterectomy has been proved to be an effective stroke prevention procedure. However, there are still inconsistencies between the results of different preoperative evaluation methods, which may sometimes complicate treatment plans. This study measured the discrepancies between different angiographic grading methods and attempted to further assess the accuracy of the carotid duplex examination according to these different angiographic grading methods. Methods. One hundred seventy‐one preendarterectomy carotid duplex examinations and angiograms were reviewed. All angiograms were measured blindly by one of the authors using the North American Symptomatic Carotid Endarterectomy Trial (N), the European Carotid Surgery Trial (E), and the common carotid (C) methods. The measurement results were further converted into the area of stenosis indices (N2, E2, and C2, respectively). By using regression testing, all results could be compared. The duplex examination data were then compared with the results of different angiographic measurement methods to evaluate their accuracy. Results. The measurement results of all angiographic grading methods were well correlated. Using different angiographic grading systems as the gold standard, duplex examination for screening endarterectomy candidates produced the following results: According to the N method, accuracy was 74%; according to the E method, accuracy was 90%; and according to the C method, the accuracy rate was 92%. According to N2, accuracy was 88%; according to E2, accuracy was 94%; and according to C2, the accuracy rate was 93%. Conclusions. The measurement results of all 3 commonly used angiographic grading methods were linearly correlated with one another. (It is important to note that none of those standards should be treated as the only gold standard.) In this study, the duplex criteria have a greater accuracy rate according to E or C rather than N. However, this study also demonstrated that the cut point of the Doppler criteria is the determinant factor for accuracy rather than which gold standard was compared. Through careful adjustment of the cutoff criteria, carotid duplex can be highly accurate, despite the use of different reference standards.
Brain Microembolism
Authors: Aly Ahmed , Babikian Viken L. , Berest Glenn , Artinian Mihran , Forteza Alejandro , Kase Carlos S.
Published: November 2009

Purpose. To alert clinicians about the occurrence of a subtype of brain infarction, its suspected etiology, and its detection by specific neuroimaging techniques. Methods. The article presents 5 nonconsecutive patients admitted to the stroke services of 2 tertiary care hospitals, who presented with acute or subacute symptoms suspicious, but at times atypical, of brain ischemia. Findings. Each patient had evidence of 3 to > 20 small areas of recent brain infarction detected by diffusion‐weighted imaging (DWI). When available, brain computerized tomography images were not helpful for the diagnosis of these recent infarcts. Most lesions were present on magnetic resonance imaging fluid‐attenuated inversion recovery sequences, but the diffusion‐weighted images allowed the determination of their acuity. Further evaluation revealed a potential source of embolism in each patient. Brain microembolism was suspected in all cases. Conclusion. Small and multiple areas of acute or subacute brain infarction occasionally present with clinical features atypical for brain embolism. They can be detected by magnetic resonance DWI studies.
Dynamics of Dotlike Hemosiderin Spots Associated With Intracerebral Hemorrhage
Authors: Imaizumi Toshio , Chiba Masahiko , Honma Toshimi , Yoshikawa Junpei , Niwa Jun
Published: November 2009

The authors observed dotlike, low‐intensity spots in T2*‐weighted magnetic resonance imaging (MRI), subsequently diagnosed histologically as previous microbleeds associated with lipofibrohyalinosis, amyloid angiopathy, and small vessel disease. The nature of dotlike hemosiderin spots (dotHSs), however, is still unknown. This case report seeks to demonstrate the dynamics of dotHSs associated with an intracerebral hematoma (ICH). T2*‐weighted MRI of a 72‐year‐old man with a history of hypertension demonstrated 4 dotHSs 24 months after a left putaminal hemorrhage. Follow‐up T2*‐weighted MRI 40 months after the acute event demonstrated the asymptomatic formation of 3 more dotHSs, even with good control of blood pressure. Fifty months after the stroke, T2*‐weighted MRI showed that 2 of the new dotHSs had become fainter, whereas the hemosiderin associated with the ICH scar remained detectable. To the authors' knowledge, this is the first description of dotHS dynamics associated with ICH.
Acute Stroke Syndrome With Fixed Neurological Deficit and False‐Negative Diffusion‐Weighted Imaging
Authors: Wang Wei , Goldstein Steven , Scheuer Mark L. , Branstetter Barton F.
Published: November 2009

Diffusion‐weighted imaging (DWI) is sensitive for the detection of acute ischemic stroke. However, a negative DWI study of the brain does not always exclude a patient from the possibility of acute cerebral ischemia. The authors report 1 case in which the patient presented with a fixed ischemic neurological deficit (National Institute of Health Stroke Scale score = 22) that included global aphasia, right hemiparesis, and a right visual field neglect. The initial DWI of the brain within 27 hours of symptom onset was negative. The deficit persisted, and a repeat magnetic resonance imaging study 7 days later showed a large area of restricted diffusion involving the gray matter of the entire left middle cerebral artery and anterior cerebral artery distribution, indicating a large area of cortical stroke.
Water Apparent Diffusion Coefficient and T2 Changes in the Acute Stage of Maple Syrup Urine Disease: Evidence of Intramyelinic and Vasogenic‐Interstitial Edema
Authors: Righini Andrea , Ramenghi Luca A. , Parini Rossella , Triulzi Fabio , Mosca Fabio
Published: November 2009

Background. The acute phase of the neonatal classical form of maple syrup urine disease (MSUD) is usually associated with generalized brain edema. Methods and Results. The authors present the case of a newborn infant in the acute stage of the classical form of MSUD in whom a remarkable decrease in the water apparent diffusion coefficient (ADC) in advanced myelinating white matter areas was associated with an increase in the T2 signal. This diffusion magnetic resonance imaging (MRI) pattern appears to be compatible with a rare kind of cytotoxic edema, the so‐called intramyelinic edema. At the same time, an increase in the ADC was seen in unmyelinated areas together with an increase in the T2 signal, a sign of a coexistent vasogenic‐interstitial edema. Conclusions. ADC measurements in MSUD provide more specific information than conventional MRI about the pathophysiology of white matter changes.
Harmonic Imaging in Acute Stroke: Detection of a Cerebral Perfusion Deficit With Ultrasound and Perfusion MRI
Authors: Meyer Karsten , Wiesmann Martin , Albers Thomas , Seidel Günter
Published: November 2009

Perfusion harmonic imaging of the brain is a new ultrasound technique for assessing cerebral perfusion. In a patient with acute middle cerebral artery infarction, this method detected a cerebral perfusion deficit corresponding to the area of delayed perfusion as displayed by perfusion magnetic resonance imaging.
Nonpulsatile Cerebral Perfusion in Takayasu's Arteritis
Authors: Lee Yong‐Seok , Yoon Byung‐Woo , Roh Jae‐Kyu
Published: November 2009

A nonpulsatile cerebral perfusion may be encountered in an artificial cardiopulmonary bypass used in cardiac surgery, which is exceptional in physiological conditions. The authors report on a 37‐year‐old woman with Takayasu's arteritis (TA) who had been suffering from progressive visual loss and recurrent seizures. Ocular findings of chronic ischemia and multiple, subcortical, high‐signal lesions in magnetic resonance (MR) imaging were indicative of significant hemodynamic impairment. MR angiography showed the complete occlusion of the innominate artery, the left common carotid artery (CCA), and the subclavian artery from the orifice of the aortic arch. The patient's transcranial Doppler (TCD) waveform was flat throughout all segments of the intracranial arteries. Intravenous acetazolamide injection confirmed the severe impairment of vasoreactivity. After a bypass graft from the aorta to the left CCA, flow velocity and pulsatility were dramatically increased without postoperative complications. A nonpulsatile cerebral perfusion indicates severe hemodynamic impairment and is partially reversible by a surgical bypass graft. TCD seems to be useful to detect “high‐risk” patients and to follow up in TA.
Paradoxical Emboli from Calf and Pelvic Veins in Cryptogenic Stroke
Authors: Cramer Steven C. , Maki Jeffrey H. , Waitches Gayle M. , D'Souza Neisha , Grotta James C. , Burgin W. Scott , Kramer Larry A.
Published: November 2009

Purpose. The increased prevalence of patent foramen ovale in patients with cryptogenic strokes suggests the occurrence of paradoxical embolism. The identification of deep venous thromboses (DVTs) in this population would strengthen this hypothesis. The purpose of this study was to image the subdiaphragmatic venous system in a cohort of patients with cryptogenic strokes. Materials and Methods. In 37 patients with cryptogenic brain ischemia and interatrial communication, duplex studies of calf, popliteal, and femoral veins, and magnetic resonance imaging venograms of the pelvis veins were performed. Results. In 10 patients, DVTs were diagnosed that were considered to be the cause of cryptogenic brain ischemia on probable (n = 6) or possible (n = 4) bases. In these patients, the median time from stroke to DVT was 3.25 days. In 5 of these 10 patients, DVTs did not involve popliteal and femoral veins, areas thought most important to pulmonary embolism, but instead were isolated to calf or pelvic veins. Although none of these 10 patients had abnormal blood hyper‐coagulation tests, 8 of the 10 did have clinical conditions suggesting predisposition to developing DVTs, such as concomitant neoplasms or pulmonary embolism. Conclusions. Increased evidence for paradoxical embolism may emerge when diagnostic strategies use multiple imaging methods and evaluate a broad extent of the subdiaphragmatic veins.
The Prevalence of Asymptomatic Intracranial Large‐Vessel Occlusive Disease: The Role of Diabetes
Authors: Elmore Erin M. , Mosquera Aurelio , Weinberger Jesse
Published: November 2009

Objective. To investigate the prevalence of asymptomatic intracranial stenosis using transcranial Doppler ultrasonography in patients with evidence of asymptomatic carotid stenosis. Background. Symptomatic atherosclerotic intracranial largeartery stenosis accounts for approximately 10% of ischemic strokes annually. It is unknown whether a significant risk for stroke is associated with asymptomatic intracranial stenosis, especially in patients with known asymptomatic carotid disease. Design and Methods. Transcutaneous real‐time B‐mode Doppler ultrasonography was performed on 510 patients referred for the evaluation of asymptomatic carotid bruits. A peak systolic flow velocity > 1.40 m/s indicated carotid stenosis. Transcranial Doppler ultrasound was performed to identify intracranial large‐artery disease. The peak systolic flow velocity indicating stenosis was > 120 cm/s for anterior circulation and > 100 cm/s for posterior circulation. Demographic and cerebrovascular risk factor information was recorded at the time of examination. Chi‐square analysis with Pearson correction was performed to examine the significance of the findings. Results. Five hundred ten patients (252 male, 258 female) aged 71.4±10.45 years were studied. The laboratory's accuracy was previously established as 93% for each technique for laboratory certification. Two hundred patients (39.2%) were found to have extracranial carotid stenosis, and 66 (12.9%) were found to have intracranial stenosis. Thirty‐seven patients (56%, P < .01) were found to have concurrent stenosis. In patients with intracranial stenosis, 19 (28.8%, P < .03) had diabetes, and 26 (39.4%, p < .03) had coronary disease. There was no corresponding correlation with extracranial carotid disease and diabetes or coronary artery disease. Conclusions. The prevalence of patients with asymptomatic intracranial stenosis with concurrent carotid stenosis was greater than expected. Coexisting diabetes and coronary disease were significant risk factors in this population. Doppler ultrasonography may be a useful technique in delineating asymptomatic intracranial stenosis in those patients with existing carotid stenosis. Further studies are needed to clarify the risk of this population for stroke from asymptomatic intracranial stenosis and to determine optimal therapy.
Brain CT and MRI Findings in 100 Consecutive Patients with Intracranial Tuberculoma
Authors: Wasay Mohammad , Kheleani Bhojo A. , Moolani Mahesh K. , Zaheer Jazia , Pui Margaret , Hasan Sheema , Muzaffar Suhail , Bakshi Rohit , Sarawari Arif R.
Published: November 2009

Objective. The characteristics of intracranial tuberculoma on computed tomography (CT) and magnetic resonance imaging (MRI) are not well known. The authors reviewed the features of tuberculoma on CT scans and MRI. The authors also correlated the MRI characteristics on various pulse sequences with neuropathological findings. Methods. The charts of patients with intracranial tuberculoma were consecutively reviewed during the period from 1988 to 1999. The diagnosis of tuberculoma was based on pathology (n = 19), clinical or neuroimaging response to tuberculous chemotherapy (n = 57), or evidence of systemic tuberculosis (n=24). Neuropathological specimens of tuberculoma were graded for the amount of fibrosis, gliosis, necrosis, and cell types (lymphocytes, macrophages, plasma cells). Results. One hundred patients (43 men) were identified. The age range was 1 to 75 years (mean = 30 y). The number of lesions ranged from 1 to > 100 (mean = 4.5 lesions/patient). Thirty‐one patients had solitary lesions, whereas 69 had multiple lesions. Thirty‐seven patients had hydrocephalus. After contrast administration, >450 lesions were seen on CT and MRI images in all 100 scans. The diameter of these enhancing lesions ranged from 1 mm to 5 cm. Lesions > 1 cm showed varied enhancement, including irregular shapes, ringlike shapes, open rings, and lobular patterns. Targetlike lesions were seen in only 2 patients. Other features included cortical and subcortical infarcts (12 patients), calcification (10% of lesions), edema (33 patients), meningeal enhancement (12 patients), mass effect, and/or midline shift (18 patients). A hypointense core with a hyperintense rim was the most common signal characteristic on T2‐weighted MRI. The central hypointensity on T2‐weighted and fluid‐attenuated inversion recovery (FLAIR) images reflected extensive necrosis and hypercellularity. Conclusion. Multiple tuberculomas and infratentorial locations were more common in the authors'patient population than in previous reports. The MRI signal characteristics of intracranial tuberculoma are extremely diverse. An isointense or hypointense core with a hyperintense rim on T2‐weighted and FLAIR images is the most common presentation. Core hypointensity of lesions on these images is related to necrosis and the large number of cells.
Symmetry of Cerebral Hemodynamic Indices Derived from Bilateral Transcranial Doppler
Authors: Schmidt Eric A. , Piechnik Stefan K. , Smielewski Piotr , Raabe Andreas , Matta Basil F. , Czosnyka Marek
Published: November 2009

Objective. The authors evaluated with bilateral transcranial Doppler (TCD) ultrasonography the norm of interhemispheric difference for several cerebrovascular hemodynamic parameters. Methods. Forty‐four volunteers (33 male, 11 female; average age = 21 years; range, 20–23 years) were studied. The authors recorded bilateral systolic, diastolic, and mean flow velocity (FV) and noninvasive systolic, diastolic, and mean arterial blood pressure. Calculated indices included Gosling's pulsatility index (GPI), an index of autoregulation (Mx), critical closing pressure (CCP), and a noninvasive estimator of cerebral perfusion pressure (nCPP). All indices were averaged per side and patient. For each parameter, the left‐right correlation coefficient (r2) and the 95% confidence limit of the left‐right differences were calculated. Results. All TCD‐derived indices displayed significant correlations between the left and right sides: r2=0.49 for mean FV (FVm), r2=0.66 for GPI, r2=0.79 for Mx, r2=0.93 for CCP, and r2=0.94 for nCPP. The 95% confidence intervals for the left‐right differences were 20 cm/s for FVm, 0.16 for GPI, 0.18 for Mx, 13 mm Hg for CCP, and 4.6 mm Hg for nCPP. Conclusions. This study gives the reference values for the assessment of left‐right symmetry of cerebral hemodynamics using various TCD‐derived indices. These reference values should be useful for clinical studies assessing the left‐right asymmetry of cerebral hemodynamics on a daily basis.
Magnetic Resonance Imaging of Meningoradiculomyelitis in Early Disseminated Lyme Disease
Authors: Tullman Mark J. , Delman Bradley N. , Lublin Fred D. , Weinberger Jesse
Published: November 2009

Lyme disease, a multisystem illness caused by the spirochete Borrelia burgdorferi, is the most common vector‐borne disease in the United States. There are 3 clinical stages of Lyme disease: early localized, early disseminated, and late persistent disease. Neuroborreliosis, infection of the nervous system by B. burgdorferi, may occur during early disseminated or late persistent disease. Spinal cord involvement in early disseminated disease is extremely rare. In patients with early disseminated neuroborreliosis, treatment with antibiotics often leads to rapid recovery and may prevent further complications of Lyme disease. The authors present the clinical and radiographic findings, both before and after treatment, in a patient with meningoradiculomyelitis due to early disseminated Lyme disease.
Pituitary Apoplexy in the Setting of Coronary Angiography
Authors: Skljarevski Vladimir , Khoshyomn Sami , Fries Timothy J.
Published: November 2009

Pituitary apoplexy (PA) is a rare but potentially life‐threatening event. Typically, it results from hemorrhage into a pituitary adenoma, although cases affecting the intact gland have been reported. PA may occur spontaneously or in a setting of certain diagnostic and therapeutic procedures. The association of PA and contrast administration in the setting of neuroimaging have been postulated. The authors report a case of PA following coronary angiography. To the best of the authors'knowledge, this scenario has not been previously reported. A 66‐year‐old woman with a congenital septal defect underwent coronary angiography that was technically uncomplicated. After the procedure, the patient experienced retro‐orbital pain and developed ophthalmoplegia. Magnetic resonance imaging (MRI) showed a hemorrhagic sellar mass extending into the cavernous sinus. A 3‐month follow‐up MRI revealed cystic changes. The patient expired 4 months later because of cardiorespiratory failure. PA in the absence of adenoma was confirmed on autopsy. The authors hypothesize that apoplexy here was related to the administration of Omnipaque in combination with the anticoagulation effect of heparin.
Roles for Imaging in Understanding the Pathophysiology, Clinical Evaluation, and Management of Patients with Mitochondrial Disease
Authors: Parry A. , Matthews P. M.
Published: November 2009

Primary mitochondrial disorders remain uncommon, but they enter into the differential diagnosis for a broad range of syndromes. Functional and structural imaging methods offer important clinical tools for patient assessment when these diseases are suspected. Although the findings are not specific, in the appropriate clinical context, these tests can guide the use of more specific or invasive investigations. They have provided considerable information concerning the underlying pathophysiology of this heterogeneous range of disorders. Monitoring these changes potentially facilitates the identification of new therapies and their individualization.
Thalamic Involvement in Multiple Sclerosis: A Diffusion‐Weighted Magnetic Resonance Imaging Study
Authors: Fabiano Andrew J. , Sharma Jitendra , Weinstock‐Guttman Bianca , Munschauer Frederick E. , Benedict Ralph H. B. , Zivadinov Robert , Bakshi Rohit
Published: November 2009

Background and Purpose. Injury to deep gray matter structures in multiple sclerosis (MS) has been suggested by recent neuroimaging and neuropathology studies. Diffusion‐weighted magnetic resonance imaging (MRI) can assess tissue damage with greater sensitivity than conventional MRI. The authors'objective was to assess thalamic gray matter damage by diffusion‐weighted imaging in MS patients. Methods. This was a retrospective study performed at a tertiary care, university‐affiliated comprehensive MS center of 82 MS patients and 43 controls. The main outcome measures were thalamic apparent diffusion coefficients (ADCs), whole‐brain atrophy (brain parenchymal fraction), fluid‐attenuated inversion recovery (FLAIR) hyperintense lesion volume, and clinical course. Results. ADCs in the left thalamus were higher in MS patients (0.741 ± 0.044 × 10−3 mm2/s) than controls (0.723 ± 0.036 × 10−3 mm2/s) (P= .027) and higher in secondary progressive MS patients (0.761 ± 0.044 × 10−3 mm2/s) than relapsing‐remitting MS patients (0.735 ± 0.032 × 10−3 mm2/s) (P= .029). ADCs in the right thalamus were higher in secondary progressive MS patients (0.784 ± 0.069 × 10−3 mm2/s) than controls (0.757 ± 0.038 × 10−3 mm2/s) (P= .033). In the MS group, left thalamus ADCs correlated negatively with brain parenchymal fraction (r= ‐0.30, P= .008), total left hemispheric FLAIR lesion volume correlated with ADCs in the left (r= 0.35, P= .001) and right (r= 0.39, P < .001) thalami, and total right hemispheric FLAIR lesion volume correlated with ADCs in the left (r= 0.31, P= .006) and right thalami (r= 0.22, P= .048). Conclusion. MS patients have increased water diffusion in the thalamus that is partly associated with clinical course, lesion load, and whole‐brain atrophy. Both indirect and direct mechanisms of gray matter injury may play a role in the pathophysiology of MS.
Contrast M‐Mode Power Doppler Ultrasound in the Detection of Right‐to‐Left Shunts: Utility of Submandibular Internal Carotid Artery Recording
Authors: Topçuoglu M. A. , Palacios I. F. , Buonanno F. S.
Published: November 2009

Cardiac right‐to‐left shunts (RLSs) can be detected by echo‐cardiography and transcranial Doppler ultrasound (TCD). In patients without adequate transtemporal bone windows, results may be obtained by insonating extracranial arteries; however, the sensitivity and practicality of this approach is unknown. In 34 patients evaluated with echocardiography for RLSs, 73 studies were performed with unilateral, simultaneous contrast TCD (cTCD) of the middle cerebral artery (MCA) and anterior cerebral artery (ACA) and submandibular power M‐mode Doppler (PMD)ultrasound of the extracranial internal carotid artery (ecICA). The number of microbubble (MB) signals and their times of first appearance were determined. RLS volume was graded on 6 levels (I = trace, II = small, III = medium, IVa = large, IVb = shower, IVc = curtain) and compared between MCA and ecICA recordings. In 2 of 24 cTCD studies in 15 patients without evidence of RLSs on single‐gated MCA monitoring, low‐volume RLSs (grades I and II) were detected via ecICA insonation; in both, MB signatures were tracked in the ecICA, passing into the ipsilateral ACA. In 40 of 49 studies (26 patients) in which RLSs were demonstrated with single‐gated MCA monitoring, more MBs were detected in the ecICA than the MCA, with either single‐gated or M‐mode images, with increases of 76.9% and 66.1%, respectively (P= .027). Compared to single‐gated studies, M‐mode technology detected nonsignificant increases in MB number in both the MCA and the ecICA (by 20.2% and 14.0%, respectively). Contrast PMD with cervical ICA recording is at least as sensitive and specific as the traditional MCA method in detecting RLSs; furthermore, this method seems to be more sensitive for low‐volume RLSs (grades I‐III) because of air MB decay (9.2%) and entry into the ipsilateral ACA (34.2%). This is in concordance with the increase of detected RLS grades observed in 32.7% of patients with echocardiography‐documented RLSs. The authors therefore suggest the incorporation of ecICA PMD not only in patients with poor ultrasonic bone windows but also in every patient being evaluated for suspected RLSs.
Diffusion‐Weighted Echo‐Planar MRI of the Brain with Calculated ADCs: A Useful Tool in the Differential Diagnosis of Tumor Necrosis from Abscess?
Authors: Dorenbeck U. , Butz B. , Schlaier J. , Bretschneider T. , Schuierer G. , Feuerbach S.
Published: November 2009

Background and Purpose. It was the aim of this study to evaluate whether brain abscesses could be distinguished reliably from necrotic brain tumors using diffusion‐weighted imaging (DWI) with calculated apparent diffusion coefficients (ADCs). Methods. The authors studied 27 lesions in 26 patients (21 tumors and metastases, 5 pyogenic brain abscesses, and 1 cerebral toxoplasmosis). DWI was obtained with a single‐shot echo‐planar imaging spin‐echo sequence. ADCs were calculated for all images. Results. ADCs (× 10−3 mm2/s) measured in the necrotic parts of the tumors ranged from 2.94 (glioblastoma) to 1.51 (astrocytoma III). In the inflammatory lesions, ADCs ranged between 0.91 and 3.07 (cerebral toxoplasmosis and pyogenic abscess). The contrast‐enhanced parts of the lesions showed ADC values from 0.77 (pyogenic abscess) up to 1.68 (glioblastoma). Conclusions. DWI with calculated ADC values does not allow the reliable differentiation of enhanced central necrotic intracranial lesions.
Volume Flow in the Common Carotid Artery does not Decrease Postprandially
Authors: Eicke Bernhard Martin , Seidel Elisabeth , Krummenauer Frank
Published: November 2009

Background and Purpose. A commonplace explanation for postprandial fatigue is the assumption of the redistribution of perfusion from the cerebral to the mesenterial territory. However, this assumption has never been scientifically proven. Methods. Because approximately 70% of the blood flow in the common carotid artery (CCA) is directed to the internal carotid artery, this vessel can be seen as a major brain‐supplying artery. Flow volume in the CCA can be measured by color M‐mode duplex sonography. The authors investigated the flow volume rate in 20 healthy volunteers before and after the intake of a high‐energy meal. Heart rate, blood pressure, and expiratory CO2 were also measured at both times. Results. There was a significant (P= .001) increase in right, left, and net CCA flow volume postprandially (right: from 362.0 [interquartile range 315.5–410.5] to 401.5 [322.1–486.4] mL/min; left: from 384.5 [345.5–439.0] to 414.5 [357.9–527.7] mL/min; net: from 756.0 [683.0–822.5] to 832.4 [713.7–967.26] mL/min). This increase was paralleled by a statistically significant increase in heart rate from 66 (58–70) to 76 (63–84) bpm, but without substantial correlation (r= 0.28) with the volume flow changes. There was no correlation with any other tested parameter. Conclusions. The authors conclude that the assumption of global brain hypoperfusion in the postprandial state cannot serve as an explanation for postprandial fatigue.
Endovascular Treatment of a Left Carotid Artery “Bowtie” Pseudoaneurysm with a Covered Wallgraft Stent
Authors: Koenigsberg Robert A. , Urrutia Victor , McCormick Daniel , Alani Firas , Ryu David , Nair Bronwyn , Thomas Carole
Published: November 2009

The authors present an unusual case of a young male patient with a large left common carotid artery pseudoaneurysm in a shape similar to that of a bowtie treated with a covered Wallgraft. The Wallgraft is a covered stent originally designed to be used in the treatment of tracheobronchial fistula and peripheral arterial applications. The favorable out‐come of this case illustrates its endovascular application in nonsurgical traumatic injuries of the carotid artery.