bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cerebral spinal fluid contamination of the measurement of the apparent diffusion coefficient of water in acute stroke
Authors: Latour Lawrence L. , Warach Steven 
Published: September 2002

AbstractThe measurement of the apparent diffusion coefficient (ADC) of water in brains of stroke patients is used in models developed to help distinguish reversible from irreversible ischemic injury. The ADC by conventional methods may be overestimated by the presence of cerebral spinal fluid (CSF) in sulci and perivascular spaces. In this study the hypothesis that DWI with CSF suppression (FLAIR‐DWI) would result in different ADC values than those obtained with the conventional DWI technique was investigated. Thirty‐one patients with stroke onset of less than 6 hr and an acute lesion on conventional DWI were studied. Both conventional isotropic DWI and FLAIR‐DWI were performed using a single‐shot echo‐planar technique. In all 31 patients, CSF‐suppressed ADC was lower than conventional ADC. The mean (SD) of the 31 patients' lesion ADC was 0.64 (0.08) × 10−3 mm2 s−1 with FLAIR‐DWI and 0.72 (0.09) × 10−3 mm2 s−1 with conventional DWI (P < 0.001). The overestimation of ADC in conventional DWI corresponded to the percentage of the voxel that contained CSF. Suppression of CSF leads to lesion ADC values that are more homogeneous and more than 15% lower than those obtained with conventional DWI techniques. This suggests that FLAIR‐DWI ADC measurements are more accurate than conventional ADC maps. Magn Reson Med 48:478–486, 2002. Published 2002 Wiley‐Liss, Inc.
Novel methodology for the archiving and interactive reading of clinical magnetic resonance spectroscopic imaging
Authors: Alger Jeffry R. , Frew Andrew J. , Cloughesy Timothy F. , del Vecchio Walter , Villablanca J. Pablo , Curran John G. 
Published: September 2002

AbstractArchiving clinical magnetic resonance spectroscopic imaging (MRSI) data and presenting the data to specialists (e.g., neuroradiologists, neurosurgeons, neurologists, neuro‐oncologists, and MR scientists) who work in different physical locations is a practical problem of significance. This communication describes a novel solution. The study hypothesis was that it is possible to use widely available distributed computing techniques to create a clinical MRSI user interface addressable from any personal computer with a suitable network connection. A worldwide web MRSI archive and interface system was created that permits the user to interactively view individual MRSI voxel spectra with correlation to MR images and to parametric spectroscopic images. Web browser software (i.e., Netscape and Internet Explorer) permits users in various physical locations to access centrally archived MRSI data using a variety of operating systems and client workstations. The system was used for archiving and displaying more than 1000 clinical MRSI studies performed at the authors' institution. The system also permits MRSI data to be viewed via the Internet from distant locations worldwide. The study illustrates that widely available software operating within highly distributed electronic networks can be used for archiving and interactive reading of large amounts of clinical MRSI data. Magn Reson Med 48:411–418, 2002. © 2002 Wiley‐Liss, Inc.
Simultaneous diffusion MRI measurements from multiple perfused rat hippocampal slices
Authors: Shepherd Timothy M. , Blackband Stephen J. , Wirth Edward D. 
Published: September 2002

AbstractRat brain slices provide a controllable tissue model in which to investigate the biophysical basis of diffusion‐weighted magnetic resonance (MR) signal changes observed clinically in nervous tissue after ischemic injury. This study describes a new multislice perfusion chamber that allows for the simultaneous acquisition of diffusion‐weighted MR images from multiple perfused rat hippocampal slices (eight slices in the present study). These images had a signal‐to‐noise ratio (SNR) of 48 ± 3 at b = 8080 s/mm2, which was sufficient to analyze the multicomponent diffusion properties of water in rat hippocampal slices. The tissue water diffusion parameters (ffast = 0.527 ± 0.041, Dfast = 1.268 ± 0.087 × 10–3 mm2/s, and Dslow = 0.060 ± 0.003 × 10–3 mm2/s) were stable for at least 8 hr after slice procurement (ANOVA, P > 0.05), suggesting that it may be possible to study the acute temporal evolution of diffusion changes in multiple brain slices following experimental perturbation. Magn Reson Med 48:565–569, 2002. © 2002 Wiley‐Liss, Inc.
Rapid method for correction of CSF partial volume in quantitative proton MR spectroscopic imaging
Authors: Horská A. , Calhoun V.D. , Bradshaw D.H. , Barker P.B. 
Published: September 2002

AbstractPartial volume effects with cerebrospinal fluid (CSF), if uncorrected, can lead to underestimation of metabolite concentrations in quantitative proton magnetic resonance spectroscopic imaging (MRSI) of the brain. A rapid method for the correction of CSF partial volume effects is described based on selective CSF imaging using long echo time (TE) fast spin echo (FSE) magnetic resonance imaging (MRI). In order to achieve maximum suppression of signal from brain parenchyma, the FSE sequence is coupled with an inversion recovery (IR) pulse. Scan time is minimized using single shot (SS) IR‐FSE. The method is validated against a current “gold standard” for the determination of CSF volumes, namely, segmented 3D spoiled gradient‐echo (SPGR) scans. Excellent agreement in CSF percentage determined by the two methods was found (linear regression analysis: slope = 0.99 ± 0.02, intercept = 2.08 ± 0.45; mean ± standard errors, R = 0.93) in pooled data from four healthy subjects. An example of the use of SS‐IR‐FSE for partial volume correction in a leukodystrophy patient with T2 hyperintense lesions is demonstrated. SS‐IR‐FSE is a simple and rapid method for applying partial volume corrections in quantitative proton MRSI, which may be of particular value in the clinical environment when time constraints do not allow longer, perhaps more accurate segmentation methods to be used. Magn Reson Med 48:555–558, 2002. © 2002 Wiley‐Liss, Inc.
Time‐resolved, undersampled projection reconstruction imaging for high‐resolution CE‐MRA of the distal runoff vessels
Authors: Du J. , Carroll T.J. , Wagner H.J. , Vigen K. , Fain S.B. , Block W.F. , Korosec F.R. , Grist T.M. , Mistretta C.A. 
Published: September 2002

AbstractImaging of the blood vessels below the knee using contrast‐enhanced (CE) MRI is challenging due to the need to coordinate image acquisition and arrival of the contrast in the targeted vessels. Time‐resolved acquisitions have been successful in consistently capturing images of the arterial phase of the bolus of contrast agent in the distal extremities. Although time‐resolved exams are robust in this respect, higher spatial resolution for the depiction of tight stenoses and the small vessels in the lower leg is desirable. A modification to a high‐spatial‐resolution T1‐weighted pulse sequence (projection reconstruction‐time resolved imaging of contrast kinetics (PR‐TRICKS)) that improves the through‐plane spatial resolution by a factor of 2 and maintains a high frame rate is presented. The undersampled PR‐TRICKS pulse sequence has been modified to double the spatial resolution in the slice direction by acquiring high‐spatial‐frequency slice data only after first pass of the bolus of contrast agent. The acquisition reported in the present work (PR‐hyperTRICKS) has been used to image healthy volunteers and patients with known vascular disease. The temporal resolution was found to be beneficial in capturing arterial phase images in the presence of asymmetric filling of vessels. Magn Reson Med 48:516–522, 2002. © 2002 Wiley‐Liss, Inc.
In vivo monitoring of hepatic glutathione in anesthetized rats by 13C NMR
Authors: Macdonald Jeffrey M. , Schmidlin Olga , James Thomas L. 
Published: September 2002

AbstractA method for in vivo 13C NMR monitoring of hepatic glutathione (GSH) in intact, anesthetized rats has been developed. Studies were conducted using a triple‐tuned, surgically implanted surface coil designed for this animal model. The coil permitted complete decoupling and sufficient resolution in the 13C NMR spectrum to monitor the time course of hepatic 13C‐metabolites of intravenously administered 2‐13C‐glycine, particularly GSH at 44.2 ppm and serine signals at 61.1 and 57.2 ppm, respectively. It further allowed concomitant monitoring of high‐energy phosphagens and intracellular pH by 31P NMR. To confirm in vivo NMR peak assignments, we compared high‐resolution 2D 1H{13C} heteronuclear multiple quantum coherence and 1D 13C spectra of hepatic perchloric acid extracts to those of authentic standards. The fractional isotopic enrichment of hepatic 13C‐glycine increased exponentially at a rate of 1.68 h−1 and reached its plateau level of 81% in 2 h. The 13C fractional isotopic enrichment of GSH increased exponentially at a rate of 0.316 h−1 and reached 55% after 4 h of 2‐13C‐glycine infusion, but without achieving a plateau. To confirm that the resonance at 44.2 ppm resulted from GSH, a rat was given an intravenous dose of 2‐oxothiazolidine‐4‐carboxylic acid (OTC), a cysteine precursor that increases intracellular GSH. As expected, with OTC administration the hepatic 13C GSH‐to‐glycine peak area increased more than sevenfold. Magn Reson Med 48:430–439, 2002. © 2002 Wiley‐Liss, Inc.
Orientational diffusion reflects fiber structure within a voxel
Authors: von dem Hagen Elisabeth A.H. , Henkelman R. Mark 
Published: September 2002

AbstractSeveral new MR techniques have been introduced to infer direction through diffusion in multiple nerve fiber bundles within a voxel. To date, however, there has been no physical model reported to evaluate these methodologies and their ability to determine fiber orientation. In this article a model of diffusion analogous to nerve fibers is presented. Diffusion measurements at multiple closely spaced angles of 15° in samples with different fiber orientations are compared with theoretical calculations for restricted diffusion in cylindrical geometry. Orientational diffusion measurements are shown to reflect fiber geometry and theoretical predictions to within 10%. Simulations of fiber crossings within a voxel suggest fiber orientation does not correspond to the direction of the largest measured diffusion coefficient, but theoretical knowledge of signal decay curves can predict the shape of these diffusion coefficient contours for given fiber orientation probabilities. Magn Reson Med 48:454–459, 2002. © 2002 Wiley‐Liss, Inc.
Neuronal control and monitoring of initiation of movements
Authors: Stuphorn Veit , Schall Jeffrey D. 
Published: September 2002

AbstractThe prerequisite for behavioral self‐control is the ability to initiate actions and to cancel planned actions. A rational choice about which action to initiate or to withhold must be informed by the consequences of prior actions. The neuronal correlates of these processes have been studied with the countermanding paradigm. This task requires subjects to withhold planned movements in response to an imperative stop signal, which they can do with varying success. By recording the activity of single neurons in different parts of the frontal cortex of macaque monkeys performing this task, signals that are sufficient for controlling the initiation and inhibition of movements and other signals that evaluate the consequences of these movements have been identified. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 326–339, 2002
Malignant MCLeod myopathy
Authors: Jung Hans H. , Brandner Sebastian 
Published: September 2002

AbstractMild myopathy is a common manifestation of the X‐linked McLeod neuroacanthocytosis syndrome. We present a patient with McLeod syndrome and a primarily subclinical myopathy, who developed severe rhabdomyolysis with renal insufficiency after a prolonged period of excessive motor restlessness due to an agitated psychotic state and a single dose of clozapine. Other possible causes for rhabdomyolysis such as prolonged immobility, trauma, hyperthermia, generalized seizures, toxin exposure, or metabolic changes were excluded. Clinical course was favorable, with persistent slight elevation of serum creatine kinase levels caused by the underlying myopathy. Our findings suggest that McLeod myopathy is a predisposing factor for severe rhabdomyolysis. This possibly life‐threatening condition should be added to the clinical spectrum of McLeod syndrome, and serum creatine kinase levels should be carefully monitored in patients with this syndrome, particularly if a hyperkinetic movement disorder is present or neuroleptic medication is used. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 424–427, 2002
Sensory‐predominant, painful, idiopathic neuropathy: Inflammatory changes in sural nerves
Authors: Kelkar Praful , McDermott Wendy R. , Parry Gareth J. 
Published: September 2002

AbstractSensory‐predominant, painful, idiopathic neuropathies are a common clinical problem. In this retrospective study of 11 patients with such a neuropathy, we found axonal loss in 9, with multifocal axonal loss in 4 patients; there were large perivascular mononuclear inflammatory infiltrates (>50 cells) in 4 and smaller infiltrates (10–20 cells) in 4. These findings suggest that some cases of this neuropathy may be due to autoimmune vasculopathy and therefore may respond to immunotherapy. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 413–416, 2002
Refinements in nerve to muscle neurotization
Authors: Becker Michael , Lassner Franz , Fansa Hisham , Mawrin Christian , Pallua Norbert 
Published: September 2002

AbstractA modified surgical technique is introduced, enabling restoration of muscle function with direct muscular neurotization. Reliable clinical outcomes result from this technique. We report on a series of 10 patients in whom the supplying motor nerve had been lost at the level of the neuromuscular junction as the result of trauma or tumor resection. Our modification of the operative technique ensures a wide distribution of nerve fibers throughout the remaining muscle tissue and produces a mean motor recovery of M4 after a period of 1 to 2 years. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 362–366 2002
Predictive power of motor unit potential parameters in anal sphincter electromyography
Authors: Podnar Simon , Mrkaić Mićo 
Published: September 2002

AbstractThe diagnostic utility of motor unit potential (MUP) parameters is usually based exclusively on their diagnostic sensitivity, disregarding specificity. In the present study, advanced statistical methods were used to determine MUP parameters with the highest predictive power for the separation of neuropathic and normal external anal sphincter (EAS) muscles. Using multi‐MUP analysis, 3,720 MUPs from 138 muscles of 52 patients with cauda equina lesion and 2,526 from 112 muscles of 64 controls were obtained. Only two principal components (PCs), which put weight on the MUP area and amplitude, were needed to explain all the data variability. On logistic and probit regression analyses, MUP area, duration, and number of turns gave results identical to all MUP parameters. Our results suggest that only these three MUP parameters are needed, and that they are as effective as PCs, in MUP analysis of chronic neuropathic EAS muscles. Reduced number of MUP parameters is expected to simplify MUP analysis and increase its specificity. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 389–394, 2002
Ultrasound therapy facilitates the recovery of acute pressure‐induced conduction block of the median nerve in rabbits
Authors: Paik Nam‐Jong , Cho Soo‐Hun , Han Tai Ryoon 
Published: September 2002

AbstractThough the use of ultrasound for the treatment of carpal tunnel syndrome (CTS) or compression neuropathy has been described, its effect remains controversial. A test model of acute CTS was developed using rabbits. Acute median nerve compression was induced by the infusion of saline into the carpal tunnel under general anesthesia to elevate the intracarpal pressure. A reduction in the compound muscle action potential (CMAP) amplitude of the abductor pollicis was noted after intracarpal pressure increased. To investigate the efficacy of ultrasound in acute CTS, rabbits with acute median nerve compression were divided into 3 groups (10 each) and ultrasound was applied at different intensities to each group as follows: 1.5 W/cm2 to group 1; 0.2 W/cm2 to group 2; 0.0 W/cm2 (sham) to group 3. A total of 10 treatment sessions were given over a period of 2 weeks. Following ultrasound application, the CMAP amplitudes showed significant improvement in group 1 compared to the other two groups (P < 0.05), indicating facilitated recovery from acute CTS in this pressure‐induced median nerve compression rabbit model. The benefits of ultrasound application in a clinical setting must be verified by further clinical trials. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 356–361, 2002
MMG and EMG responses during fatiguing isokinetic muscle contractions at different velocities
Authors: Perry‐Rana Sharon R. , Housh Terry J. , Johnson Glen O. , Bull Anthony J. , Berning Joseph M. , Cramer Joel T. 
Published: September 2002

AbstractThe purpose of this study was to determine mechanomyographic (MMG) and electromyographic (EMG) responses of the superficial quadriceps muscles during repeated isokinetic contractions in order to provide information about motor control strategies during such activity, and to assess uniformity in mechanical activity (MMG) between the investigated muscles. Ten adults performed 50 maximal concentric muscle contractions at three randomly selected contraction velocities (60, 180, and 300°·s−1) on different days. Surface electrodes and an MMG sensor were placed on the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). EMG and MMG amplitude and peak torque (PT) were calculated for each contraction, normalized, and averaged across all subjects. The results demonstrated that MMG amplitude more closely tracked the fatigue‐induced decline in torque production at each velocity than did EMG amplitude. This indicates that MMG amplitude may be useful for estimating force production during fatiguing dynamic contractions when a direct measure is not available, such as during certain rehabilitative exercises. MMG amplitude responses of the VL, RF, and VM were not uniform for each velocity or across velocities, indicating that it may be possible to detect the individual contribution of each muscle to force production during repeated dynamic contractions. Therefore, MMG amplitude may be clinically useful for detecting abnormal force contributions of individual muscles during dynamic contractions, and determining whether various treatments are successful at correcting such abnormalities. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 367–373, 2002
Intrapartum maternal lumbosacral plexopathy
Authors: Katirji Bashar , Wilbourn Asa J. , Scarberry Susan L. , Preston David C. 
Published: September 2002

AbstractThere are many conflicting theories regarding the mechanism and prognosis of acute foot drop during labor. We report seven women who had arrested labor and foot drop. Six had short stature and one had a large newborn. All had weakness of ankle dorsiflexion, eversion, and inversion, and sensory loss in the L‐5 dermatome. Superficial peroneal sensory nerve action potentials (SNAPs) were small or absent in six patients, and the sural SNAP was attenuated in one. Peroneal compound muscle action potential (CMAP) amplitude (recording from extensor digitorum brevis) was low in five, whereas the tibial CMAP was normal in all patients. Peroneal CMAP amplitude (recording from the tibialis anterior) was normal in three and small in three. Needle electromyography revealed decreased recruitment and fibrillation potentials in L‐5–innervated muscles, mostly below the knee. We conclude that intrapartum foot drop occurs mostly in short women and is caused by lumbosacral trunk compression by the fetal head at the pelvic brim. The primary pathology is predominantly demyelination and recovery is complete in up to 5 months. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 340–347; 2002
The medial antebrachial cutaneous nerve: Antidromic and orthodromic conduction studies
Authors: Seror Paul 
Published: September 2002

AbstractMedial antebrachial cutaneous nerve (MABCN) conduction studies were performed antidromically and orthodromically in 70 control subjects to determine normal values and define the lower limits of normality. The mean sensory action potential (SAP) amplitudes were 17.7 and 17.5 μV and the sensory conduction velocities were 60 and 61 m/s, respectively, with the antidromic and orthodromic techniques. With both techniques, no SAP amplitude was lower than 6 μV. The lower limits of normal of the interside amplitude ratio were 1.66 when both techniques were used and 2.0 when only one was used. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 421–423, 2002
Mechanical properties of the electrically silent adult rat soleus muscle
Authors: Roy Roland R. , Zhong Hui , Monti Ryan J. , Vallance Kevin A. , Edgerton V.R. 
Published: September 2002

AbstractThe isometric and isotonic in situ mechanical properties of the soleus muscle of adult female rats were determined after 60 days of inactivity induced by spinal cord isolation (SI). Compared to control, the absolute muscle mass, physiological cross‐sectional area, and maximum tetanic tension of the soleus in SI rats were reduced by 69%, 66%, and 77%, respectively. Isometric twitch time‐to‐peak‐tension and half‐relaxation times were 41% and 60% shorter in SI than control rats. The maximum velocity of shortening (mm/s), as determined using the afterloaded technique, was 66% faster in SI than control rats, whereas unloaded shortening velocity was similar in the two groups (9% faster in SI rats). Peak power was 48% lower in SI than control rats. The SI soleus was 39% more fatigable than control. Thus, the soleus became a smaller, faster, and more fatigable muscle following 60 days of inactivity. In general, the results indicate that the adaptations are of a lesser magnitude than those reported previously following denervation for the same duration. These data provide a baseline for future efforts to experimentally define the mechanisms of neurally mediated, but activity‐independent, regulation of the mechanical properties of the rat soleus muscle. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 404–412, 2002
Embedding iterated line digraphs in books
Authors: Hasunuma Toru 
Published: September 2002

AbstractIn this paper, we present an upper bound on the pagenumber of an iterated line digraph Lk(G) of a digraph G. Our bound depends only on the digraph G and is independent of the number of iterations k. In particular, it is proved that the pagenumber of Lk(G) does not increase with the number of iterations k. This result generalizes previous results on book‐embeddings of some particular families of iterated line digraphs such as de Bruijn digraphs, Kautz digraphs, and butterfly networks. Also, we apply our result to wrapped butterfly networks. © 2002 Wiley Periodicals, Inc.