bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated quality control protocol for MR spectra of brain tumors
Authors: Wright Alan J. , Arús Carles , Wijnen Jannie P. , Moreno‐Torres Angel , Griffiths John R. , Celda Bernardo , Howe Franklyn A. 
Published: May 2008

AbstracteTUMOUR (http://www.etumour.net/) is acquiring a large database of brain tumor 1H MR spectra to develop automated pattern recognition methods and decision support system (DSS) for tumor diagnosis. Development of accurate pattern‐recognition algorithms requires spectra undistorted by artifacts, low signal‐to‐noise, or broad lines. eTUMOUR currently uses panels of expert spectroscopists to subjectively grade spectra as being acceptable or unacceptable. Automated quality control (QC) would be more satisfactory for several reasons: 1) to provide a reproducible objective classification of spectrum quality; 2) for use within the future DSS to prevent misdiagnosis due to poor spectrum quality; 3) to rapidly process the very large datasets of 1H spectra being accrued. An automated QC method using independent component analysis for feature extraction with a least‐squares support vector machine classifier is presented. Separate training (n = 144) and test sets (n = 98) of single‐voxel spectra from brain tumors and other lesions were acquired at multiple clinical centers with short and long echo times. Pairs of expert spectroscopists classified the test set an average of 85% the same. The automated QC classification agreed with an expert for 87% of test spectra, on average, suggesting the method classifies spectrum quality as accurately as expert spectroscopists. Magn Reson Med 59:1274–1281, 2008. © 2008 Wiley‐Liss, Inc.
Axcaliber: A method for measuring axon diameter distribution from diffusion MRI
Authors: Assaf Yaniv , Blumenfeld‐Katzir Tamar , Yovel Yossi , Basser Peter J. 
Published: May 2008

AbstractThe diameter of a myelinated nerve axon is directly proportional to its conduction velocity, so the axon diameter distribution helps determine the channel capacity of nervous transmission along fascicles in the central (CNS) and peripheral nervous systems (PNS). Previously, this histological information could only be obtained using invasive tissue biopsies. Here we propose a new NMR‐based approach that employs a model of water diffusion within “restricted” cylindrical axons to estimate their diameter distribution within a nerve bundle. This approach can be combined with MRI to furnish an estimate of the axon diameter distribution within each voxel. This method is validated by comparing the diameter distributions measured using the NMR and histological techniques on sciatic and optic nerve tissue specimens. The axon diameter distribution measured in each voxel of porcine spinal cord using MRI and using histological methods were similar. Applications are expected in longitudinal studies designed to follow nerve growth in normal and abnormal development, as well as in diagnosing disorders and diseases affecting specific populations of axons in the CNS and PNS. Magn Reson Med 59:1347–1354, 2008. © 2008 Wiley‐Liss, Inc.
Rapid and efficient mapping of regional ventilation in the rat lung using hyperpolarized 3He with Flip angle variation for offset of RF and relaxation (FAVOR)
Authors: Santyr Giles E. , Lam Wilfred W. , Ouriadov Alexei 
Published: May 2008

AbstractA novel imaging method is presented, Flip Angle Variation for Offset of RF and Relaxation (FAVOR), for rapid and efficient measurement of rat lung ventilation using hyperpolarized helium‐3 (3He) gas. The FAVOR technique utilizes variable flip angles to remove the cumulative effect of RF pulses and T1 relaxation on the hyperpolarized gas signal and thereby eliminates the need for intervening air wash‐out breaths and multiple cycles of 3He wash‐in breaths before each image. The former allows an improvement in speed (by a factor of ≈30) while the latter reduces the cost of each measurement (by a factor of ≈5). The FAVOR and conventional ventilation methods were performed on six healthy male Brown Norway rats (190–270 g). Lobar measurements of ventilation, r, obtained with the FAVOR method were not significantly different from those obtained with the conventional method for the right middle and caudal and left lobes (P > 0.05 by a Wilcoxon matched pairs test). A methacholine challenge test was also administered to an animal and reduction and recovery of r was detected by the FAVOR method. The reduced 3He consumption and the improvement in speed provided by FAVOR suggest that it may allow measurement of ventilation in human subjects not previously possible. Magn Reson Med 59:1304–1310, 2008. © 2008 Wiley‐Liss, Inc.
Fast slice‐selective radio‐frequency excitation pulses for mitigating B inhomogeneity in the human brain at 7 Tesla
Authors: Zelinski Adam C. , Wald Lawrence L. , Setsompop Kawin , Alagappan Vijayanand , Gagoski Borjan A. , Goyal Vivek K. , Adalsteinsson Elfar 
Published: May 2008

AbstractA novel radio‐frequency (RF) pulse design algorithm is presented that generates fast slice‐selective excitation pulses that mitigate B inhomogeneity present in the human brain at high field. The method is provided an estimate of the B field in an axial slice of the brain and then optimizes the placement of sinc‐like “spokes” in kz via an L1‐norm penalty on candidate (kx, ky) locations; an RF pulse and gradients are then designed based on these weighted points. Mitigation pulses are designed and demonstrated at 7T in a head‐shaped water phantom and the brain; in each case, the pulses mitigate a significantly nonuniform transmit profile and produce nearly uniform flip angles across the field of excitation (FOX). The main contribution of this work, the sparsity‐enforced spoke placement and pulse design algorithm, is derived for conventional single‐channel excitation systems and applied in the brain at 7T, but readily extends to lower field systems, nonbrain applications, and multichannel parallel excitation arrays. Magn Reson Med 59:1355–1364, 2008. © 2008 Wiley‐Liss, Inc.
Monitoring prostate thermal therapy with diffusion‐weighted MRI
Authors: Chen Jing , Daniel Bruce L. , Diederich Chris J. , Bouley Donna M. , van den Bosch Maurice A.A.J. , Kinsey Adam M. , Sommer Graham , Pauly Kim Butts 
Published: May 2008

AbstractFor MR‐guided minimally invasive therapies, it is important to have a repeatable and reliable tissue viability evaluation method. The use of diffusion‐weighted MRI (DWI) to evaluate tissue damage was assessed in 19 canine prostates with cryoablation or high‐intensity ultrasound (HIU) ablation. The apparent diffusion coefficient (ADC) trace value was measured in the treated tissue immediately upon the procedure and on the posttreatment follow‐up. For the acute lesions, the ADC value decreased to (1.05 ± 0.25) × 10–3 mm2/s, as compared to (1.64 ± 0.24) × 10–3 mm2/s before the treatment. There was no statistical difference between previously frozen or previously ultrasound‐heated lesions in terms of the 36% ADC reduction (P = 0.66). The ADC decrease occurred early during the course of the treatment, which appears to complicate DWI‐based thermometry. Over time, the ADC value increased as the tissue recovered and regenerated. This study shows that DWI could be a promising method to monitor prostate thermal therapies and to provide insight on tissue damage and tissue remodeling after injury. Magn Reson Med 59:1365–1372, 2008. © 2008 Wiley‐Liss, Inc.
Water spin dynamics during apoptotic cell death in glioma gene therapy probed by T1ρ and T2ρ
Authors: Sierra A. , Michaeli S. , Niskanen J.‐P. , Valonen P.K. , Gröhn H.I. , Ylä‐Herttuala S. , Garwood M. , Gröhn O.H. 
Published: May 2008

AbstractLongitudinal and transverse relaxations in the rotating frame, with characteristic time constants T1ρ and T2ρ, respectively, have potential to provide unique MRI contrast in vivo. On‐resonance spin‐lock T1ρ with different spin‐lock field strengths and adiabatic T2ρ with different radiofrequency‐modulation functions were measured in BT4C gliomas treated with Herpes Simplex Virus thymidine kinase (HVS‐tk) gene therapy causing apoptotic cell death. These NMR tools were able to discriminate different treatment responses in tumor tissue from day 4 onward. An equilibrium two‐site exchange model was used to calculate intrinsic parameters describing changes in water dynamics. Observed changes included increased correlation time of water associated with macromolecules and a decreased fractional population of this pool. These results are consistent with destructive intracellular processes associated with cell death and the increase of extracellular space during the treatment. Furthermore, association between longer exchange correlation time and decreased pH during apoptosis is discussed. In this study, we demonstrated that T1ρ and T2ρ MR imaging are useful tools to quantify early changes in water dynamics reflecting treatment response during gene therapy. Magn Reson Med 59:1311–1319, 2008. © 2008 Wiley‐Liss, Inc.
Resolution of creatine and phosphocreatine 1H signals in isolated human skeletal muscle using HR‐MAS 1H NMR
Authors: Chen Jin‐Hong , Wu Yuhsin V. , DeCarolis Penelope , O'Connor Rachael , Somberg C. Joy , Singer Samuel 
Published: May 2008

AbstractProton NMR spectra of freshly isolated human skeletal muscle samples contain creatine and phosphocreatine resonances with distinct chemical shifts that are easily visualized with magic angle spinning (MAS, spinning the sample rapidly at 54.7° with respect to the magnetic field) methods. The identification of the phosphocreatine resonance was based on two findings: that (i) the possible small dipolar coupling does not contribute to line splitting under rapid MAS, and (ii) the 1H signal decreases concurrently with the phosphocreatine resonance observed in 31P NMR experiments. In the MAS 1H spectra, the phosphocreatine resonance remains a singlet with a linewidth of less than 3 Hz. The creatine resonances are split into two peaks with linewidths at half height of approximately 2 and 6 Hz, respectively. The resonance with the broader linewidth represents creatine that is significantly motion‐restricted and suggests that a creatine pool in muscle tissue is highly compartmentalized. Magn Reson Med 59:1221–1224, 2008. © 2008 Wiley‐Liss, Inc.
1H MR spectroscopic imaging of phospholipase‐mediated membrane lipid release in apoptotic rat glioma in vivo
Authors: Liimatainen Timo J. , Erkkilä Arja T. , Valonen Piia , Vidgren Helvi , Lakso Merja , Wong Garry , Gröhn Olli H.J. , Ylä‐Herttuala Seppo , Hakumäki Juhana M. 
Published: May 2008

AbstractThe purpose of the current study was to determine regional spatiotemporal differences and to gain insight on the mechanisms responsible for lipid accumulation during apoptotic cell death using in vivo MR spectroscopic imaging in combination with histology and biochemical membrane lipid analyses. Rats bearing BT4C gliomas were treated with ganciclovir (GCV) for 14 days, and combined in vivo quantitative MR spectroscopic imaging (MRSI) of gliomas with histology and a biochemical analysis of major cell membrane constituents. By using 1H MRSI in vivo in combination with histology, we were able to demonstrate previously unattainable regional lipid concentration differences in tumors during GCV‐induced apoptosis, with 5‐μL tissue volume resolution. Our results also show that, during treatment, phospholipase A2 (PLA2) expression is significantly elevated by 37 ± 13% (P < 0.05) and tumor cell membranes loose a significant proportion of unsaturated fatty acyl moieties (56 ± 6 mmol/kg, P < 0.05). These changes are reflected in both histology and significant MR‐visible lipid accumulation, demonstrating that phospholipid hydrolysis in tissue undergoing apoptosis can be imaged with MRSI. Our work demonstrates the versatility of 1H MRSI in studying apoptosis in vivo, which is likely to pave way for the use of MRSI in both experimental and clinical anticancer trials. Magn Reson Med 59:1232–1238, 2008. © 2008 Wiley‐Liss, Inc.
Respiratory self‐gated four‐dimensional coronary MR angiography: A feasibility study
Authors: Lai Peng , Larson Andrew C. , Park Jaeseok , Carr James C. , Li Debiao 
Published: May 2008

AbstractThe four‐dimensional (4D) coronary MR angiography (MRA) approach has been developed to eliminate the need for accurate determination of the acquisition window and trigger delay time. Diaphragm navigator (NAV) has been the conventional respiratory gating method for free‐breathing coronary MRA. However, NAV echo acquisition interrupts the continuous radiofrequency pulse application required for 4D steady‐state free precession coronary MRA. The objective of this work was to investigate the feasibility of a respiratory self‐gating (RSG) technique for 4D coronary MRA and its effectiveness by comparing with retrospective NAV gating. Data were acquired continuously throughout the cardiac cycle and retrospectively remapped to cardiac phases based on the electrocardiogram signal simultaneously recorded. An RSG signal extracted from a direct measurement of the heart position was used for retrospective respiratory gating and motion correction. In seven healthy volunteers, 4D MRA images were reconstructed, allowing retrospective assessment of the cardiac motion of the coronary artery and selection of the images with the best vessel delineation. Statistical analysis shows that 4D RSG provides coronary artery delineation comparable to mid‐diastole images acquired using NAV. Respiratory self‐gating is an effective method for eliminating respiratory motion artifacts and allows 4D coronary MRA during free breathing. Magn Reson Med 59:1378–1385, 2008. © 2008 Wiley‐Liss, Inc.
B1‐insensitive fast spin echo using adiabatic square wave enabling of the echo train (SWEET) excitation
Authors: Madhuranthakam Ananth J. , Busse Reed F. , Brittain Jean H. , Rofsky Neil M. , Alsop David C. 
Published: May 2008

AbstractAbdominal images at 3T acquired with fast spin echo (FSE) sequences often exhibit signal voids due to RF transmit field inhomogeneities. Theory suggests, however, that the repeated refocusing pulses of FSE are capable of maintaining signal even at reduced RF amplitudes if the magnetization is suitably prepared. Here we propose a modified excitation strategy for FSE that is more robust to transmit field inhomogeneities than conventional FSE. The new excitation approach replaces the standard 90° excitation pulse with a discretely sampled hyperbolic secant pulse that creates a square wave longitudinal magnetization as a function of gradient and off‐resonance induced phase shifts between the subsequent echoes of the FSE sequence. This pulse is followed by the conventional train of refocusing pulses except that the first few pulses increase from near zero to the desired refocusing amplitude. Simulations and in vivo results at 3T indicate preserved image quality and much greater robustness of this new sequence to nonuniform RF fields. This robustness comes at the cost of 20% reduction in signal when the RF field is uniform and increased motion sensitivity. This RF field‐insensitive sequence may overcome challenges of body imaging at high field and in patients with ascites. Magn Reson Med 59:1386–1393, 2008. © 2008 Wiley‐Liss, Inc.
Glial fibrillary acidic protein: A marker of axonal Guillain–Barrè syndrome and outcome
Authors: Notturno Francesca , Caporale Christina M. , De Lauretis Angelo , Uncini Antonino 
Published: May 2008

AbstractGlial fibrillary acid protein (GFAP) is increased in serum and cerebrospinal fluid of patients with dementia, traumatic brain injury, stroke, and multiple sclerosis. To determine whether GFAP is increased in Guillain–Barré syndrome (GBS) we evaluated serum GFAP in 30 controls, 20 patients with acute inflammatory demyelinating neuropathy (AIDP), and 17 with primary axonal GBS. Serum GFAP levels were increased in axonal GBS (median, 0.74) compared with controls (median, 0.41; P < 0.0001) and AIDP (median, 0.58; P = 0.0015). GFAP levels correlated with Hughes grades (serum r = 0.74; P < 0.0001) 6 months after neuropathy onset. Applying the cutoff value in serum of 0.63 to the diagnosis of axonal GBS, we obtained a sensitivity of 76.5% and a specificity of 86%. Thus, serum GFAP levels may be used in GBS as a diagnostic marker of the axonal variant and to predict outcome. Muscle Nerve, 2008
Obturator mononeuropathy caused by lipomatosis of the nerve: A case report
Authors: Nardone Raffaele , Venturi Alessandro , Ladurner Gunther , Golaszewski Stefan , Psenner Konrad , Tezzon Frediano 
Published: May 2008

AbstractWe report a patient who presented with the clinical features of obturator mononeuropathy. Abdomino‐pelvic computed tomography revealed a fusiform mass in the right perivesical space; magnetic resonance imaging (MRI) showed characteristic “coaxial‐cable‐like” appearance in cross‐section and “spaghetti‐like” appearance in longitudinal section, pathognomonic of lipomatosis of the nerve. Nerve lipomatosis as the cause of obturator neuropathy has not been previously reported. MRI provides definite and graphic proof of the diagnosis. Muscle Nerve, 2008
Effect of small motor unit potentials on the motor unit number estimate
Authors: van Dijk Johannes P. , Zwarts Machiel J. , Schelhaas Helenius J. , Stegeman Dick F. 
Published: May 2008

AbstractSmall surface motor unit potentials (S‐MUPs) may have a negative influence on the variability of the motor unit number estimate (MUNE). According to published consensus criteria S‐MUPs with a negative peak amplitude smaller than 10 μV should be omitted. The effect of omitting small S‐MUPs on the MUNE was evaluated using a simulation model. The model incorporated a healthy and amyotrophic lateral sclerosis (ALS) distribution formed with real S‐MUPs. Using a random drawing process the MUNE was calculated with and without small S‐MUPs. In the healthy population 27% of all S‐MUPs were small. MUNE determined without these S‐MUPs was marginally less variable. However, MUNE values dropped about 24% at a sample size of 20. In ALS, only 12% of the total population of 130 S‐MUPs were small. MUNE dropped about 12% without the small S‐MUPs. By omitting small S‐MUPs the differences between the healthy and ALS distributions become smaller. Therefore, incorporating small S‐MUPs in the estimate is suggested. © 2008 Wiley Periodicals, Inc. Muscle Nerve, 2008
Nine‐year case history of monofocal motor neuropathy
Authors: Manganelli Fiore , Pisciotta Chiara , Iodice Rosa , Calandro Sara , Santoro Lucio 
Published: May 2008

AbstractA 36‐year‐old man had a 6‐year history of progressive left hand and finger extension weakness. Extensive electrophysiological studies showed only a partial motor conduction block along the left radial nerve at the mid‐arm. Several intravenous immunoglobulin treatments were clinically successful. A 3‐year follow‐up did not show any clinical or electrophysiological involvement of other nerves. A monofocal motor neuropathy, as a variant of multifocal motor neuropathy, was diagnosed. Muscle Nerve, 2008
PAX3/7 expression coincides with myod during chronic skeletal muscle overload
Authors: Hyatt Jon‐Philippe K. , McCall Gary E. , Kander Elizabeth M. , Zhong Hui , Roy Roland R. , Huey Kimberly A. 
Published: May 2008

AbstractPaired box (Pax) proteins 3 and 7 are key determinants for embryonic skeletal muscle development by initiating myogenic regulatory factor (MRF) gene expression. We show that Pax3 and 7 participate in adult skeletal muscle plasticity during the initial responses to chronic overload (≤7 days) and appear to coordinate MyoD expression, a member of the MRF family of genes. Pax3 and 7 mRNA were higher than control within 12 h after initiation of overload, preceded the increase in MyoD mRNA on day 1, and peaked on day 2. On days 3 and 7, Pax7 mRNA remained higher than control, suggesting that satellite cell self‐renewal was occurring. Pax3 and 7 and MyoD protein levels were higher than control on days 2 and 3. These data indicate that Pax3 and 7 coordinate the recapitulation of developmental‐like regulatory mechanisms in response to growth‐inducing stimuli in adult skeletal muscle, presumably through activation of satellite cells. Muscle Nerve, 2008
Hormonal and nutritional control of L‐carnitine uptake in myoblastic C2C12 cells
Authors: Borgne Françoise Le , Rigault Caroline , Georges Béatrice , Demarquoy Jean 
Published: May 2008

AbstractL‐Carnitine plays an important role in skeletal muscle bioenergetics, and its bioavailability and thus its import may be crucial for muscle function. We studied the effect of thyroid hormone, insulin, and iron overload, hormones and nutrients known to alter muscle metabolism, on L‐carnitine import into C2C12 cells. We report here L‐carnitine uptake is increased by thyroid hormones and decreased by iron. Insulin was found to be ineffective in altering the L‐carnitine uptake. Muscle Nerve, 2008
Chronic inflammatory demyelinating polyneuropathy–like disorder associated with amyotrophic lateral sclerosis
Authors: Rajabally Yusuf A. , Jacob Saiju 
Published: May 2008

AbstractThe association between demyelinating neuropathy and amyotrophic lateral sclerosis (ALS) has been reported rarely. We report four patients who presented with clinical features and investigations suggestive of a neuropathy but who later progressed and received a final diagnosis of ALS according to the original El Escorial criteria. Three patients met the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) 2006 definition for “definite” chronic inflammatory demyelinating polyneuropathy (CIDP), as well as the American Academy of Neurology (AAN) 1991 and Nicolas et al. [2002] electrodiagnostic criteria for CIDP. Two of them showed segmental demyelination on teased‐fiber preparations and one had a raised cerebrospinal fluid protein level. Another patient met the Nicolas et al. CIDP criteria and presented with brachial plexus hyperintensity on T2‐weighted magnetic resonance imaging, indicative of an inflammatory process. No significant objective response to immunomodulatory treatment was observed in any of these patients who all subsequently progressed unfavorably. Muscle Nerve, 2008
Adolescent spinal muscular atrophy with calf hypertrophy and a deletion in the SMN gene
Authors: Yiu Eppie M. , Ravat Sangeeta , Ryan Monique M. , Shield Lloyd K. , Smith Lindsay J. , Kornberg Andrew J. 
Published: May 2008

AbstractSpinal muscular atrophy (SMA) is generally associated with proximal weakness and muscle wasting. An X‐linked variant with calf hypertrophy has been reported. We describe a young man with SMA type 4 with prominent calf hypertrophy in whom DNA analysis showed a homozygous deletion of exons 7 and 8 in the telomeric copy of the survival motor neuron gene. Calf hypertrophy may be seen uncommonly in autosomally inherited SMA. Muscle Nerve, 2008