bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intravascular Ultrasound Doppler Measurement of Blood Flow Velocity
Authors: Schumacher M. , Yin L. , Swaid S. , Oldenburger J. , Gilsbach J. M. , Hetzel A. 
Published: November 2009

ABSTRACT Background and Methods. The authors investigated the feasibility and accuracy of intravascular Doppler sonography (IVDS) with a newly developed microprobe. Methods. The known method to determine blood flow velocity by transcutaneous Doppler sonography was transferred to an intravascular usable Doppler probe. With the improved technique, a microprobe measuring 0.3 mm in diameter can be advanced through a 5F catheter used in routine diagnostic angiography to perform intravascular Doppler sonography. In a first step, the conditions for application and measurement were studied in a flow tube model and were transferred in a second step to patients undergoing routine angiography and patients with arterial stenoses. Results. Measurements with nondegassed liquids showed a high intensive acoustic signal, but no echo effect could be recorded in degassed liquids. IVDS of healthy vessels in 40 patients showed the same typical flow pulse curve as seen in transcutaneous measurements. The optimal position of the microprobe with respect to the contact of the vessel wall, the diastolic and systolic phase, and the distance to the tip of the catheter could be evaluated. In 95.6% of the 40 patients with healthy vessels, IVDS was successful. Fourteen patients with arterial stenotic diseases were investigated before and after percutaneous transluminal angioplasty, and the results of these investigations correlated well with the angiographical results. Conclusion. For percutaneously directly reachable vessels, the transcutaneous Doppler sonography is the choice for easy noninvasive and inexpensive measurement of blood flow velocity. However, for vessels that are difficult or impossible to reach percutaneously, intravascular measurement is a valid procedure.
SonoVue™ in Transcranial Doppler Investigations of the Cerebral Arteries
Authors: Kaps M. , Legemate D. A. , Ries F. , Ackerstaff R.G.A. , Markus H. , Pezzoli C. , Llull J.‐B. , Spinazzi A. 
Published: November 2009

ABSTRACT Background and Purpose. The authors investigated the safety and diagnostic potential of a new ultrasound contrast agent (SonoVue™) using transcranial color‐coded duplex sonography (TCCS). Methods. Forty patients were enrolled in a multicenter, open‐label (on‐site), blind (off‐site), randomized, dose‐ranging crossover study. SonoVue™ was administered as an intravenous bolus injection of 4 different dosages (0.3, 0.6, 1.2, and 2.4 mL). Efficacy was evaluated as (1) off‐site assessment of global quality of the Doppler investigation (based on color or power Doppler images and spectral analysis) at baseline and following each dose of SonoVue™ according to a 4‐point scale (from very poor to excellent imaging of blood flow) and (2) duration of clinically useful signal enhancement and color or power Doppler visualization of blood flow. Additional on‐site efficacy assessments performed following each dose of SonoVue™ included confidence in diagnosis and global consequences of contrast enhancement on diagnosis. Safety evaluations included clinical laboratory tests, neurological examination, injection site tolerability, and incidence of adverse events and their relationship to the study agent. Results. All doses of SonoVue™ significantly improved the global quality of Doppler examinations (P < .05). The median duration of clinically useful enhancement was dose related (P < .001) and ranged from 2 to 6 minutes at the highest dose. The administration of the contrast agent changed a nondiagnostic study to a diagnostic one in 66% of patients and increased the confidence in diagnosis in 74% of cases. No serious adverse events were recorded following SonoVue™ administration. The observed adverse reactions were all transient and mild in intensity. Conclusions. The results obtained from this multicenter study demonstrate that the administration of SonoVue™ to patients with ischemic cerebrovascular disease who undergo TCCS examination of cerebral vessels improves the visualization of intracranial arteries, providing a dose‐dependent contrast enhancement and a clinically useful duration of signal enhancement related to the dose. During this multicenter study, SonoVue™ proved to be a safe and well‐tolerated compound.
Effect of Adenosine on Cerebral Blood Flow Velocity
Authors: Zanferrari Carla , Razumovsky Alexander Y. , Lavados Pablo M. , Sen Souvik , Oppenheimer Stephen M. 
Published: November 2009

ABSTRACTBackground and Purpose. Evidence suggests that adenosine (ADN) is a potent vasodilator of cerebral vessels. However, the feasibility of manipulating human cerebral vascular resistance with AND has not been assessed by means of TCD. The purpose of this study was to quantitatively estimate the change in middle cerebral artery cerebral blood flow velocity (CBFV) in response to intravenous ADN infusion in humans. Methods. Eleven patients with subacute cerebrovascular events (ischemic stroke, transient ischemic attack, or hemorrhage) undergoing adenosine‐thallium stress testing were studied before, during, and after ADN infusion to evaluate the effect of ADN on cerebral blood flow velocity. Continuous blood pressure (BP), heart rate (HR), respiration rate (RR), end‐tidal CO2(ET‐CO2), and transcranial Doppler ultrasonography monitoring of CBFV and pulsatility index (PI) in both middle cerebral arteries were performed. Results. The mean CBFVs were 65.4±19.2 cm/s before, 55.4±18.1 cm/s during, and 64.1±22.5 cm/s after ADN infusion, which represents a statistically significant decrease during ADN test compared with both baseline (P= .007) and posttest levels (P= .017). The PI was increased during the test (0.91±0.2) when compared with baseline (0.71±0.1) (P= .007). During ADN injection, mean HR increased (P= .004) and mean end‐tidal CO2levels decreased significantly (P= .003). Mean BP and RR did not change significantly. Conclusions. The authors hypothesize that any direct vasodilatory effect of ADN on the distal cerebral peripheral vasculature may be negated by an effect of ADN on depth of respiration resulting in hypocapnia and secondary distal vasoconstriction.
Helical High‐Resolution Volume‐Rendered 3‐Dimensional Computer Tomography Angiography in the Detection of Intracranial Aneurysms
Authors: Seruga Tomaz , Bunc Gorazd , Klein Guenther Erich 
Published: November 2009

ABSTRACT Background and Purpose. This study was carried out to determine whether high‐resolution three‐dimensional prospective‐volume‐rendered computed tomographic (CT) angiography can replace conventional intra‐arterial digital subtractional angiography in the diagnostic evaluation of patients with an acute subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysm. Methods. Both techniques were performed in 30 consecutive patients within 2 to 12 hours after their admission to the hospital. Results. In this group of 30 patients, CT angiography with 3‐dimensional volume‐rendered reconstruction detected 31 aneurysms in 25 patients. Two aneurysms were missed on CT angiography. Conventional angiography detected 33 aneurysms in 27 patients. The authors considered angiograms in 3 patients presenting with SAH as normal. In all cases where an aneurysm was detected on CT angiography, the finding was confirmed by conventional angiography. Conclusions. CT angiography with 3‐dimensional postprocessing is a sensitive, noninvasive method that provides a 3‐dimensional view of intracranial vessels and the aneurysm. It is also very useful in planning either surgical or endovascular treatment.
Unilateral Temporal Lobe Stroke Causing Ischemic Transient Global Amnesia: Role for Diffusion‐Weighted Imaging in the Initial Evaluation
Authors: Greer David M. , Schaefer Pamela W. , Schwamm Lee H. 
Published: November 2009

ABSTRACTIschemia has been proposed as a cause of transient global amnesia (TGA), but proof has been lacking. The authors performed magnetic resonance imaging on a 77‐year‐old woman with classic TGA at 4 hours and at 6 days after the onset of symptoms. Her initial diffusion‐weighted imaging (DWI) and apparent diffusion coefficient imaging suggested an acute infarct in the left mesial temporal lobe. Follow‐up T2‐weighted imaging at 6 days confirmed the lesion as an ischemic infarct, despite resolution of her symptoms. DWI permits early detection of small ischemic lesions and may identify patients with ischemic TGA who should be evaluated for potential sources of emboli.
Intracranial Vasculitis and Multiple Abscesses in a Pregnant Woman
Authors: Cihangiroglu Mutlu , Hartker Frederick W. , Mojtahadi Saeid , Ramsey Ruth G. 
Published: November 2009

ABSTRACTCerebral vasculitis is an unusual disorder with many causes. Infectious causes of cerebral vasculitis are predominantly bacterial or viral in nature. Purulent bacterial vasculitis is most often a complication of severe bacterial meningitis. The patient is a 25‐year‐old African American female, 25 weeks pregnant, who presented to the neurology service after a consult and referral from an outside hospital. She had a 1‐month history of right sixth nerve palsy. Initial workup included a negative lumber puncture and a noninfused magnetic resonance imaging (MRI). Three days later, the patient developed right‐sided migraine headaches and right third nerve palsy. The angiogram revealed diffuse irregularity and narrowing of the petrous, cavernous, and supraclinoid portions of the internal carotid and right middle cerebral arteries. Shortly thereafter, an MRI examination revealed diffuse leptomeningeal enhancement and abscess and a right parietal subdural empyema. Infectious vasculitis secondary to purulent meningitis has a rapidly progressive course and presents with cranial nerve palsy with involvement of the cavernous sinus. Although the association of this disease with pregnancy has not been established, it should be recognized that the early imaging studies may be negative or discordant and follow‐up imaging might be necessary.
Brain Volume Changes on Longitudinal Magnetic Resonance Imaging in Normal Older People
Authors: Tang Yong , Whitman Gregory T. , Lopez Ivan , Baloh Robert W. 
Published: November 2009

ABSTRACT Background and Purpose. The purpose of this study is to investigate the longitudinal age‐related changes in human brain volume using stereological methods. Methods. Sixty‐six older participants (34 men, 32 women, age [mean ± SD] 78.9 ± 3.3 years, range 74–87 years) with normal baseline and follow‐up examinations underwent 2 MRIs (magnetic resonance imaging) of the brain on average 4.4 years apart. The volumes of the cerebrum (defined as cortex, basal ganglia, thalamus, and white matter), lateral ventricles, and cerebellum were estimated on the 2 MRIs using an unbiased stereological method (Cavalieri principle). Results. The annual decrease (mean ± SD) of the cerebral volume was 2.1%± 1.6% (P < .001). The average volume of the lateral ventricles on the second MRI was increased by 5.6%± 3.6% per year (P < .001). The average volume of the cerebellum on the second MRI was decreased by 1.2%± 2.2% per year (P < .001). Even though the average cerebral volume was significantly different between men and women on initial MRI and second MRI, the percentage change of the age‐related cerebral volume decrease in male and female brains between initial MRI and second MRI were identical. Conclusions. The findings showed that there was age‐related atrophy of cerebrum and cerebellum and age‐related disproportional enlargement of lateral ventricles in normal older men and women.
Magnetic Resonance Reflects the Pathological Evolution of Wernicke Encephalopathy
Authors: Ho Park Seong , Kim Manho , Na Duk L. , Jeon Beom S. 
Published: November 2009

ABSTRACT Background and Purpose. Wernicke encephalopathy (WE) is an acute phase of Wernicke‐Korsakoff syndrome. Pathologic findings change between acute and chronic phases. Only a few magnetic resonance imaging (MRI) studies have been done to date. Methods. To correlate the MRI findings in acute and chronic stages of WE with the known pathologic information, 15 consecutive patients with WE were examined with MRI: 3 before thiamine treatment, 7 within 24 hours of thiamine treatment, 4 between the second and sixth day after thiamine treatment, and 1 fifty‐five days after thiamine treatment. Nine of the patients had follow‐up MRI between 2 days and 33 months. T1‐weighted, proton, and T2‐weighted axial images were obtained with additional 5‐mm‐thick T1‐weighted sagittal and coronal images to better visualize the mammillary bodies. Results. In the acute WE, MRI showed high signal intensity on T2‐weighted images in periaqueduct and medial thalamic regions. In a few patients with alcoholism, vermian and mammillary body atrophies and third ventricular enlargements were noted. In the chronic phase of WE, T2 hyperintensity disappeared but mammillary bodies and cerebellar vermis became atrophic and third ventricular enlargements were evident. High signal intensity on T2‐weighted images disappeared as early as 2 days, and atrophic changes appeared as early as 1 week. Conclusion. MRI is useful for in vivo monitoring and reflects the pathological evolution in acute and chronic phases of WE.
Segmentation of Progressive Multifocal Leukoencephalopathy Lesions in Fluid‐Attenuated Inversion Recovery Magnetic Resonance Imaging
Authors: Itti Laurent , Chang Linda , Ernst Thomas 
Published: November 2009

ABSTRACT Background and Purpose. The authors compared the reproducibility of a manual and a semiautomated technique for the quantitation of white‐matter lesions in magnetic resonance imaging (MRI). Methods. Volumes of white‐matter lesions were determined using fluid‐attenuated inversion recovery MRI in 23 AIDS patients with progressive multifocal leukoencephalopathy. Manual outlining was compared to an automated method based on region growing and adaptive thresholding. Results. Lesion volumes from the 2 methods correlated well (61 lesions, r= 0.99, P < 10−4), although the volumes differed substantially (12.8%± 13.7%). Interscan, intrasubject reproducibility was better for the automated than the manual method (2.9%± 3.2% vs 12.4%± 16.2% volume difference, P= .02). Conclusion. The automated algorithm appeared more reproducible, which renders it superior to the manual method for longitudinal studies.
Cerebral Infarction in Conjunction With Patent Foramen Ovale and May‐Thurner Syndrome
Authors: Greer David M. , Buonanno Ferdinando S. 
Published: November 2009

ABSTRACTStroke patients with paradoxical embolus mandate a search for deep venous thrombosis (DVT) in the lower extremities. Iliac vein compression, or May‐Thurner syndrome, places certain patients at risk for development of DVT. The authors present 3 stroke patients with patent foramen ovale and paradoxical cerebral embolism, with demonstrated iliac vein compression as the presumed source of their embolus. May‐Thurner syndrome should be considered a potential source of clot, as definitive therapy of this disorder can be curative.
Bilateral Cerebellar Infarctions Caused by a Stenosis of a Congenitally Unpaired Posterior Inferior Cerebellar Artery
Authors: Gaida‐Hommernick B. , Smekal U. v. , Kirsch M. , Schminke U. , Machetanz J. , Kessler C. 
Published: November 2009

ABSTRACTBilateral symmetrical cerebellar infarcts in the territory supplied by the medial posterior inferior cerebellar artery (PICA) branches are extremely rare. In the few cases published, it has not been possible to clearly pinpoint the cause of this infarct pattern. The authors present the case history of a 58‐year‐old man who had acute headaches accompanied by pronounced rotatory vertigo with nausea and vomiting. The neurological examination revealed bilateral cerebellar signs. Cranial magnetic resonance imaging showed bilateral, nearly symmetrical infarcts in the territory of the medial branches of both PICAs. These bilateral PICA infarctions were caused by a stenosis of an unpaired PICA originating from the left vertebral artery supplying both cerebellar hemispheres.
Magnetic Resonance Imaging Detection of a Lesion Compatible With Central Pontine Myelinolysis in a Pregnant Patient With Recurrent Vomiting and Confusion
Authors: Valiulis Beth , Kelley Roger E. , Hardjasudarma Mardjohan , London Steven 
Published: November 2009

ABSTRACTThe authors report a patient who presented with unexplained confusion. She was 15 weeks pregnant and had been having recurrent vomiting for several weeks. This was felt to possibly represent hyperemesis gravidarum, but she had several other possible contributing factors. Her serum sodium was 146 mmol/L, and her potassium was 2.6 mmol/L. She was alert but had disorientation, visual hallucinations, memory impairment, and confabulation despite being a college graduate with no history of illicit drug use or excessive alcohol consumption. Her initial magnetic resonance imaging (MRI) brain scan was interpreted as being normal. However, her follow‐up MRI brain scan revealed typical findings of central pontine myelinolysis, which correlated with hyperreflexia and positive Babinski reflexes. This patient illustrates the constellation of signs and symptoms that can be seen with a demyelinating lesion of the pons. In addition, our case illustrates how this MRI scan finding can be quite nonspecific but may help to explain the clinical findings.
Harmonic Imaging of the Brain Parenchyma in a Dog Model Following NC100100 (Sonazoid™) Bolus Injection
Authors: Meyer Karsten , Seidel Günter , Algermissen Christian 
Published: November 2009

ABSTRACT Background and Purpose. NC100100 (Sonazoid™) is a new perfluorocarbon‐based ultrasound contrast agent (UCA) that has not been introduced to transcranial harmonic imaging. Methods. In an animal study on 6 beagle dogs, the authors performed harmonic power Doppler and gray‐scale imaging (SONOS 5500, S4 probe) after bolus injection of 2 different doses of Sonazoid. Time intensity curves for brain parenchyma, masticatory muscle, and contralateral skull were generated, and the peak increase from baseline was computed. Results. With harmonic gray‐scale imaging, a dose‐dependent homogeneous increase in acoustic intensity of the brain parenchyma was observed. Evaluation of the contralateral base of the skull showed a moderate signal decrease. In harmonic power Doppler sonography, signal increase was dose dependent also, but the signal pattern was inhomogeneous, with stronger enhancement in the anterior part of the brain. Conclusion. The new UCA Sonazoid is suitable for displaying brain perfusion. As already observed for other UCAs, gray‐scale harmonic imaging with Sonazoid leads to a more homogeneous contrast increase in cerebral parenchyma compared to harmonic power Doppler imaging. Sonazoid produces a moderate shadowing effect, with signal attenuation in the underlying deeper regions of interest.
Neuroimaging Characteristics of Pseudosubcortical Laminar Heterotopia
Authors: Montenegro Maria Augusta , Min Li Li , Guerreiro Marilisa M. , Cendes Fernando 
Published: November 2009

ABSTRACTSubcortical laminar heterotopia (SLH) is a subtype of malformation of cortical development characterized by laminar gray matter between the cortex and ventricles, which can vary in thickness and may be continuous or discontinuous. The objective of this study is to describe a normal finding of high‐resolution magnetic resonance imaging that may simulate an SLH. SLH is isointense to cortex on both T1‐ and T2‐weighted/FLAIR images, usually both anteriorly and posteriorly in location. Conversely, pseudo‐SLH is a normal variant present only at the posterior aspect of the brain, and with dark signal on both T1‐ and T2‐weighted/FLAIR images.
Misinterpretation of Parahippocampal Herniation for a Posterior Fossa Tumor: Imaging and Intraoperative Findings
Authors: Horowitz Michael , Kassam Amin , Levy Elad , Lunsford L. Dade 
Published: November 2009

ABSTRACTTumors of the hippocampal and parahippocampal gyrus are not uncommon, nor are lesions of the cerebellopontine and ambient cisterns. Lesions in these areas include astrocytomas, meningiomas, gangliogliomas, hamartomas, neurilemomas, epidermoids, and dermoids. Preoperative imaging is an important tool that can help distinguish lesions, making surgical therapy more targeted and appropriate. The authors report a case of a 41‐year‐old man with right‐sided atypical trigeminal neuralgia and a left ambient cistern abnormality that was radiologically interpreted as a mesial temporal lobe or extramedullary ambient cistern mass lesion. Surgical exploration for biopsy revealed an abnormal posterior fossa anatomy and a parahippocampal herniation into the perimesencephalic cistern. Biopsy confirmed the finding of normal brain.
Clinical Investigative Studies: Relationship Between Absolute Mean Cerebral Transit Time and Absolute Mean Flow Velocity on Transcranial Doppler Ultrasound After Ischemic Stroke
Authors: Wardlaw Joanna M. , Dennis Martin S. , Merrick Malcolm V. , Warlow Charles P. 
Published: November 2009

ABSTRACT Background and Purpose. Previous studies of transcranial Doppler (TCD) sonography in acute stroke have used the relative difference between the symptomatic and asymptomatic arteries to assess arterial occlusion. However, a simple measure of absolute mean flow velocity might provide a direct assessment of “perfusion reserve” in acute ischemic stroke. Methods. In a prospective study, 62 patients with ischemic stroke had TCD and a mean cerebral transit time examination within 48 hours of stroke. Absolute intracranial arterial mean flow velocities were correlated with the corresponding absolute mean transit times. Results. The authors found a significant correlation between middle cerebral artery (MCA) mean flow velocity and transit time in the symptomatic (Spearman rank correlation coefficient [ρ] =−0.65, P < .01) but not in the asymptomatic (ρ=−0.04, P=ns) MCA territory. Equations relating absolute mean flow velocity to absolute transit time were derived. Conclusion. The findings suggest that in the normal hemisphere (with intact autoregulation on the horizontal portion of the autoregulation curve), flow velocity and transit time are not closely related to each other, but in the symptomatic hemisphere (on the downward slope of the autoregulation curve), flow velocity is directly proportional to the transit time and, therefore, to its inverse, perfusion reserve. The use of absolute mean flow velocity values on TCD should be further explored as a simple way of assessing “perfusion” in acute ischemic stroke.