bluuebunny/crossref_metadata_2025_split huggingface dataset:
Residual Flow Signals Predict Complete Recanalization in Stroke Patients Treated With TPA
Authors: Labiche Lise A. , Malkoff Marc , Alexandrov Andrei V. 
Published: November 2009

ABSTRACT 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

ABSTRACT 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

ABSTRACT 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

ABSTRACT 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

ABSTRACTThe 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

ABSTRACTMeningovascular 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

ABSTRACT 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

ABSTRACT 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

ABSTRACT 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

ABSTRACT 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

ABSTRACTThe 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

ABSTRACTDiffusion‐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

ABSTRACT 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

ABSTRACTPerfusion 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

ABSTRACTA 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

ABSTRACT 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.