bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iterative image reconstruction for PROPELLER‐MRI using the nonuniform fast fourier transform
Authors: Tamhane Ashish A. , Anastasio Mark A. , Gui Minzhi , Arfanakis Konstantinos 
Published: June 2010

AbstractPurpose:To investigate an iterative image reconstruction algorithm using the nonuniform fast Fourier transform (NUFFT) for PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) MRI.Materials and Methods:Numerical simulations, as well as experiments on a phantom and a healthy human subject were used to evaluate the performance of the iterative image reconstruction algorithm for PROPELLER, and compare it with that of conventional gridding. The trade‐off between spatial resolution, signal to noise ratio, and image artifacts, was investigated for different values of the regularization parameter. The performance of the iterative image reconstruction algorithm in the presence of motion was also evaluated.Results:It was demonstrated that, for a certain range of values of the regularization parameter, iterative reconstruction produced images with significantly increased signal to noise ratio, reduced artifacts, for similar spatial resolution, compared with gridding. Furthermore, the ability to reduce the effects of motion in PROPELLER‐MRI was maintained when using the iterative reconstruction approach.Conclusion:An iterative image reconstruction technique based on the NUFFT was investigated for PROPELLER MRI. For a certain range of values of the regularization parameter, the new reconstruction technique may provide PROPELLER images with improved image quality compared with conventional gridding. J. Magn. Reson. Imaging 2010;32:211–217. © 2010 Wiley‐Liss, Inc.
Effect of Gd‐EOB‐DTPA on T2‐weighted and diffusion‐weighted images for the diagnosis of hepatocellular carcinoma
Authors: Saito Kazuhiro , Araki Yoichi , Park Jinho , Metoki Ryo , Katsuyama Hiroaki , Nishio Ryota , Kakizaki Dai , Moriyasu Fuminori , Tokuuye Koichi 
Published: June 2010

AbstractPurpose:To evaluate the effect of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA) on T2‐weighted imaging (T2WI) and diffusion‐weighted imaging (DWI) for the diagnosis of hepatocellular carcinoma (HCC).Materials and Methods:The phantom signal intensity was measured. We also evaluated 72 patients including 30 patients with HCC. T2WI and DWI were obtained before and then 4 and 20 min after injecting the contrast medium. The signal to noise ratio (SNR), contrast to noise ratio (CNR), and apparent diffusion coefficient (ADC) were calculated in the tumor and liver parenchyma.Results:The phantom signal intensity increased on T2WI at a concentration of contrast medium less than 0.2 mmol/L but decreased when the concentration exceeded 0.4 mmol/L. SNR of the liver parenchyma on T2WI was significantly different between before and 4 min after injecting the contrast medium, while there were no significant differences between before and 4 and 20 min after injection. On T2WI, SNR, and CNR of HCC showed no significant differences at any time. SNR, CNR, and ADC of the liver parenchyma and tumor on DWI also showed no significant differences at any time.Conclusion:It is acceptable to perform T2WI and DWI after injection of Gd‐EOB‐DTPA for the diagnosis of HCC. J. Magn. Reson. Imaging 2010;32:229–234. © 2010 Wiley‐Liss, Inc.
Magnetic resonance histologic correlation in rotator cuff tendons
Authors: Buck Florian M. , Grehn Holger , Hilbe Monika , Pfirrmann Christian W.A. , Manzanell Silvana , Hodler Juerg 
Published: June 2010

AbstractPurpose:To relate histologic changes in rotator cuff tendons to the appearance on T1‐weighted as well as fat‐suppressed T2‐weighted and proton density‐weighted magnetic resonance imaging (MRI) sequences.Materials and Methods:T1‐weighted, fat‐suppressed T2‐weighted and fat‐suppressed proton density‐weighted sequences of 18 cadaveric shoulders were acquired. The supraspinatus, infraspinatus, and subscapularis tendons were evaluated histologically. Twenty‐six abnormalities were found in 23 of 37 tendons. In addition, histologically normal tendon parts (n = 32), including three segments with normal histology but abnormal MR signal, considered to represent magic angle effects, were defined. All regions of interest (ROIs) were evaluated by two musculoskeletal radiologists independently and blinded to histology.Results:In the 26 areas with anatomically intact tendons but abnormal histological findings mucoid degeneration (n = 13), chondroid metaplasia (n = 11), fatty infiltration (n = 1), and foreign‐body granuloma (n = 1) after tendon suture were found. Compared to normal tendon, mucoid degeneration was hyperintense on T2‐weighted fat‐suppressed (P = 0.007) and on proton density‐weighted fat‐suppressed images (P = 0.006). Chondroid metaplasia was hyperintense compared to normal tendon in all sequences (P < 0.05). Mucoid degeneration was hypointense compared to chondroid metaplasia on T2‐weighted fat‐suppressed images (P = 0.038) and hypointense compared to magic angle artifacts on T1‐weighted images (P = 0.046).Conclusion:Chondroid metaplasia of rotator cuff tendons appears to be more common than expected. Both mucoid degeneration and chondroid metaplasia may explain increased tendon signal on MR images of the rotator cuff. J. Magn. Reson. Imaging 2010;32:165–172. © 2010 Wiley‐Liss, Inc.
Visualization of cerebral microbleeds with dual‐echo T2*‐weighted magnetic resonance imaging at 7.0 T
Authors: Conijn Mandy M.A. , Geerlings Mirjam I. , Luijten Peter R. , Zwanenburg Jaco J.M. , Visser Fredy , Biessels Geert Jan , Hendrikse Jeroen 
Published: June 2010

AbstractPurpose:To assess the visualization of cerebral microbleeds with dual echo T2*‐weighted imaging at 7.0 T magnetic resonance imaging (MRI).Materials and Methods:Ten consecutive participants (eight men, two women, mean age 54 ± 12 years) with vascular disease or risk factors from the second manifestations of arterial disease (SMART) study were included. Dual‐echo T2*‐weighted scans (echo time: 2.5/15.0 msec) were made for all participants at 7.0 T MRI. The number of visible microbleeds and the diameter of the microbleeds were recorded on minimal intensity projection images of both echoes.Results:The first echo image shows dark microbleeds against a homogeneous, more hyperintense signal of the brain tissue without contrast for veins and basal ganglia. In eight patients microbleeds were observed, with a total of 104 microbleeds. Of these, 88 (84.6%) were visible on the first and 102 (98.0%) on the second echo. The mean diameter of the microbleeds was 1.24 mm for the first echo and 2.34 mm for the second echo.Conclusion:T2*‐weighted imaging at two echo times at 7.0 T combines the advantages of the first and second echo. Microbleeds visible on the first echo show large contrast with the surrounding tissue, even in the presence of paramagnetic ferritin. The second echo enables visualization of smaller microbleeds than the first echo. J. Magn. Reson. Imaging 2010;32:52–59. © 2010 Wiley‐Liss, Inc.
Reproducibility of black blood dynamic contrast‐enhanced magnetic resonance imaging in aortic plaques of atherosclerotic rabbits
Authors: Calcagno Claudia , Vucic Esad , Mani Venkatesh , Goldschlager Gregg , Fayad Zahi A. 
Published: June 2010

AbstractPurpose:To investigate the short‐term reproducibility of black‐blood dynamic contrast‐enhanced (DCE) magnetic resonance imaging (MRI) in atherosclerotic rabbits to evaluate the potential of this technique to be a reliable readout of plaque progression and/or regression upon therapeutic intervention.Materials and Methods:Atherosclerotic rabbits were imaged at baseline and 24 hours later with DCE‐MRI on a 1.5T MRI system. DCE‐MRI images were analyzed by calculating the area under the signal intensity versus time curve (AUC). Intraclass correlation coefficients (ICCs) were used to evaluate interscan, intraobserver, and interobserver reproducibility. In addition, the test–retest coefficient of variation (CoV) was evaluated.Results:Statistical analyses showed excellent interscan, intraobserver, and interobserver agreement. All ICCs were greater than 0.75, P < 0.01 indicating excellent agreement between measurements.Conclusion:Experimental results show good interscan and excellent intra‐ and interobserver reproducibility, suggesting that DCE‐MRI could be used in preclinical settings as a read‐out for novel therapeutic interventions for atherosclerosis. This preliminary work encourages investigating the reproducibility of DCE‐MRI also in clinical settings, where it could be used for monitoring high‐risk patients and in longitudinal clinical drug trials. J. Magn. Reson. Imaging 2010;32:191–198. © 2010 Wiley‐Liss, Inc.
Diffusion tensor imaging of the pediatric optic nerve: Intrinsic and extrinsic pathology compared to normal controls
Authors: Nickerson Joshua P. , Salmela Michael B. , Koski Chris J. , Andrews Trevor , Filippi Christopher G. 
Published: June 2010

AbstractPurpose:To establish normative magnetic resonance diffusion tensor imaging (MRDTI) data in the pediatric optic nerve and compare to pathologic conditions both intrinsic and extrinsic to the anterior optic nerve pathway.Materials and Methods:A retrospective analysis of MRDTI at 3.0T in children ages 0–18 with both normal imaging studies and with pathologic conditions either arising from the optic nerves or exerting mass effect on the anterior optic pathways was performed. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained within the posterior part of the intraorbital optic nerves. Statistical analysis compared normal controls to optic pathway lesions.Results:Lesions intrinsic to the optic nerve including septo‐optic dysplasia and optic nerve glioma demonstrated statistically significant reductions in FA and increases in ADC values. There was no statistically significant difference in FA or mean diffusivity between the normal controls and patients with lesions extrinsic to the optic nerve but exerting mass effect on the visual pathway.Conclusion:MRDTI is a feasible technique for evaluating the optic nerves in pediatric patients. It may play a role in presurgical planning by demonstrating integrity of the visual pathway in patients with resectable lesions, allowing for minimization of morbidity associated with vision loss. J. Magn. Reson. Imaging 2010;32:76–81. © 2010 Wiley‐Liss, Inc.
Microstructural changes in patients with progressive supranuclear palsy: A diffusion tensor imaging study
Authors: Wang JiunJie , Wai YauYau , Lin Wey‐Yil , Ng ShuHang , Wang Chi‐Hong , Hsieh RenHsiang , Hsieh ChungHuang , Chen Rou‐Shayn , Lu Chin‐Song 
Published: June 2010

AbstractPurpose:To determine whether progressive supranuclear palsy (PSP) is associated with specific diffusion tensor imaging (DTI) patterns of diffusivity, anisotropy, and coherence in functionally relevant brain areas.Materials and Methods:In all, 17 PSP patients and 17 controls were scanned using a 3 T magnetic resonance imaging (MRI) scanner. Patients were assessed in the off‐medication condition using the Hoehn and Yahr staging and the United Parkinson's Disease Rating Scale, motor subscale (UPDRS‐III). Diffusion information were analyzed in relation to disease severity and subtypes.Results:Numerous changes in diffusion properties were identified in the subcortical areas. In the midbrain, fractional anisotropy (FA) decreased and MD (mean diffusivity) increased with disease progression. UPDRS‐III scores correlated positively with both FA in the caudate and MD in the pons. DTI analysis of disease subtypes demonstrated significant differences between PSP‐Parkinsonism and Steele‐Richardson‐Olszewski syndrome in axial diffusivity values in the putamen and globus pallidus, as well as in intervoxel diffusion coherence values in the middle cerebellar peduncle.Conclusion:Our findings, cautiously interpreted, demonstrate the advantage of using a functional imaging technique to aid in the specificity of defining more precisely the pathological processes taking place in white and gray matter regions in PSP. J. Magn. Reson. Imaging 2010;32:69–75. © 2010 Wiley‐Liss, Inc.
Genotype X/C recombinant (putative genotype I) of hepatitis B virus is rare in Hanoi, Vietnam—genotypes B4 and C1 predominate
Authors: Thuy Phung Thi Bich , Alestig Erik , Liem Nguyen Thanh , Hannoun Charles , Lindh Magnus 
Published: June 2010

AbstractThere are eight known genotypes of hepatitis B virus, A–H, and several subgenotypes, with rather well‐defined geographic distributions. HBV genotypes were evaluated in 153 serum samples from Hanoi, Vietnam. Of the 87 samples that could be genotyped, genotype B was found in 67 (77%) and genotype C in 19 (22%). All genotype C strains were of subgenotype C1, and the majority of genotype B strains were B4, while a few were B2. The genotype X/C recombinant strain, identified previously in Swedish patients of indigenous Vietnamese origin, was found in one sample. This variant, proposed to be classified as genotype I, has been found recently also by others in Vietnam and Laos. The current study indicates that the genotype X/C recombinant may represent approximately 1% of the HBV strains circulating in Vietnam. J. Med. Virol. 82:1327–1333, 2010. © 2010 Wiley‐Liss, Inc.
Comparison of the levels of human herpesvirus 6 (HHV‐6) DNA and cytokines in the cerebrospinal fluid and serum of children with HHV‐6 encephalopathy
Authors: Kawabe Shinji , Ito Yoshinori , Ohta Rieko , Sofue Ayako , Gotoh Kensei , Morishima Tsuneo , Kimura Hiroshi 
Published: June 2010

AbstractPrimary human herpesvirus‐6 (HHV‐6) infection is a common cause of acute sporadic encephalopathy in Japanese children. Occasionally, HHV‐6 is not detected in the cerebrospinal fluid (CSF) of patients with encephalopathy, for example, in those with focal viral encephalitis, such as herpes simplex viral encephalitis. This indicates that HHV‐6 encephalopathy is caused by an indirect mechanism, although this is not fully understood. HHV‐6 DNA, cytokines (interleukin (IL)‐1β, IL‐6, IL‐8, IL‐10, IL‐12 p70, tumor necrosis factor‐α, interferon‐γ), and matrix metalloproteinase‐9 were quantitated in both the CSF and serum of 13 patients with HHV‐6 encephalopathy during the acute phase of the disease. HHV‐6 DNA was detected in the CSF of seven patients with HHV‐6 encephalopathy. The viral DNA concentration was significantly higher in serum than in CSF (mean 1.64 × 104 vs. 5.70 × 101 copies/ml; P = 0.003). The lack or low level of viral DNA in the CSF samples suggests that direct invasion of the central nervous system by HHV‐6 is not the main cause of encephalopathy. Additionally, the IL‐10 concentration was significantly higher in serum than in CSF (P < 0.001), whereas there was no significant difference in IL‐6 levels between the CSF and serum samples. Interestingly, the IL‐8 concentration was significantly higher in CSF than in serum (P = 0.038). The distribution of these cytokines differed between CSF and serum. The high CSF concentration of IL‐8 could play an important role in the pathogenesis of encephalopathy. J. Med. Virol. 82:1410–1415, 2010. © 2010 Wiley‐Liss, Inc.
Clinical evaluation of the NS1 antigen‐capture ELISA for early diagnosis of dengue virus infection in Brazil
Authors: Castro‐Jorge Luiza A. , Machado Paula R.L. , Fávero Camila A. , Borges Marcos C. , Passos Luzia M.R. , de Oliveira Rosana Moreira , Fonseca Benedito A.L. 
Published: June 2010

AbstractThe fact that the diagnosis of infection with dengue virus is usually made by detecting IgM antibodies during the convalescent phase of the disease interferes with disease management and, consequently, with reducing mortality rates. This study evaluated the sensitivity and specificity of detection of NS1 in samples of patients suspected of acute dengue virus infection in Brazil. The results were used to institute treatment and the sensitivity and specificity of detection of NS1 were compared to the results of detection of IgM, virus isolation, and RT‐PCR. Detection of NS1 yielded better results than RT‐PCR and virus isolation. When considering IgM detection and RT‐PCR positive results as “gold standards,” the sensitivity and specificity of the NS1 assay were 95.9% and 81.1%, respectively. All patients enrolled in the study were treated promptly and had an uneventful course of the disease. The detection of NS1 provided better results than the diagnostic techniques used currently during the acute phase of disease (RT‐PCR and virus isolation). Detection of NS1 is an important tool for the diagnosis of acute dengue infection, particularly in highly endemic areas, allowing for rapid treatment of patients and reduction of disease burden. J. Med. Virol. 82:1400–1405, 2010. © 2010 Wiley‐Liss, Inc.
Poor performance of hepatitis C antibody tests in hospital patients in Uganda
Authors: Seremba E. , Ocama P. , Opio C.K. , Kagimu M. , Thomas D.L. , Yuan H.J. , Attar N. , Lee W.M. 
Published: June 2010

AbstractMost hepatitis C testing in Uganda is performed using commercial rapid strip assays (RSA) to detect antibodies to hepatitis C virus (anti‐HCV), rather than enzyme immunoassays (EIA). The prevalence of hepatitis C antibodies in a Ugandan hospital population was determined using both methods to test their accuracy using nucleic acid testing (NAT) as a reference. Sera from 380 consecutive hospitalized Ugandan patients were tested for anti‐HCV using an RSA in Uganda, with subsequent automated third‐generation EIA testing in the United States, followed by NAT. Recombinant immunoblot assays (RIBA) were used as a supplementary test to detect anti‐HCV epitopes. Overall, anti‐HCV was detected in 48/380 (13%) by one or both antibody tests. Anti‐HCV was detected in 19 (5.0%) patients by RSA and in 33 (8.7%) patients by EIA; only four patients were anti‐HCV positive by both methods. Fourteen of the 48 anti‐HCV positive patients had detectable serum HCV RNA, 7 each by bDNA assay or by PCR. RSA detected only 7 of 14 HCV RNA positive sera. Of 29 RNA negative but anti‐HCV positive patients tested by RIBA, only two were anti‐HCV positive; 27 were anti‐HCV negative or indeterminate. Anti‐HCV testing by RSA and/or EIA was neither sensitive nor specific for detection of ongoing HCV infection in hospitalized Ugandan patients. Our findings underscore the importance of confirmatory nucleic acid testing, which, despite its increased cost, appears essential to manage African patients with HCV. J. Med. Virol. 82:1371–1378, 2010. © 2010 Wiley‐Liss, Inc.
Low level myocardial parvovirus B19 persistence is a frequent finding in patients with heart disease but unrelated to ongoing myocardial injury
Authors: Lotze Ulrich , Egerer Renate , Glück Brigitte , Zell Roland , Sigusch Holger , Erhardt Christian , Heim Albert , Kandolf Reinhard , Bock Thomas , Wutzler Peter , Figulla Hans‐R. 
Published: June 2010

AbstractWhile myocardial parvovirus B19 (B19V), aside from enteroviruses (EV) and adenoviruses (ADV), has recently been found often in patients with myocarditis and idiopathic dilated cardiomyopathy (IDC), the pathogenetic significance of B19V genomes in those patients has not yet been sufficiently elucidated. In the present study, left ventricular endomyocardial biopsies from 24 patients with left ventricular ejection fraction (LVEF) below 55% due to IDC, and tissue from the right atrial appendage of 10 control patients undergoing bypass surgery with normal LVEF (>55%) were investigated for B19V, ADV, and EV genomes by specific nested polymerase chain reaction (PCR), by real time PCR or by reverse‐transcription PCR, respectively. The myocardial tissue samples from the 10 controls were analyzed each in three different virological laboratories for B19V. In the IDC group, the frequency of the myocardial virus genomes found in 54% (13/24) of the patients was as follows: B19V: 50% (12/24), EV: 8% (2/24), including one patient with B19V and EV, and ADV: 0% (0/24). For comparison, the prevalence of B19V genomes was between 30% and 60% in the control group as detected in three different laboratories, but all these control subjects were EV‐ and ADV‐negative. The number of B19V gene copies, however, was very low and similar both in the IDC and control group. In the majority of patients myocardial B19V persistence was associated with a low virus load irrespective of the underlying heart disease so that it may be of no importance in the pathogenesis of IDC. J. Med. Virol. 82:1449–1457, 2010. © 2010 Wiley‐Liss, Inc.
Correlation of HTLV‐1 Tax genetic diversity with HTLV‐1 associated myelopathy/tropical spastic paraparesis progression and HTLV‐1a genotypes in an HTLV‐1 endemic region in Argentina
Authors: Iñiguez Alena Mayo , Gastaldello René , Otsuki Koko , Balangero Marcos , Carvalho Costa Filipe , Remondegui Carlos , Paula Vicente Ana Carolina , Gallego Sandra 
Published: June 2010

AbstractThe oncoprotein Tax was characterized genetically from a large cohort of human T‐cell lymphotropic virus type 1 (HTLV‐1) seropositive individuals from the most endemic region of HTLV‐1‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) and HTLV‐1 infection in Argentina, the province of San Salvador de Jujuy. Sixteen HAM/TSP patients and 47 HTLV‐1 healthy carriers were evaluated. Six Tax genetic polymorphisms were identified and observed in 70.8% of healthy carriers and 62.5% of HAM/TSP patients. Tax genetic polymorphisms were not associated with clinical status but A8344C polymorphism statistically provide a borderline protective effect of HAM/TSP outcome. Nucleotide diversity in healthy carriers was 0.00549, whereas HAM/TSP virus population revealed a low diversity of 0.00379, suggests a positive selection for Tax protein conservation in this group. It is concluded that tax genetic polymorphisms do not increase the risk of developing HAM/TSP in this endemic region. However, in spite of the low prevalence of HTLV‐1aB genotype, statistical analysis revealed an important correlation of tax genetic signatures with HTLV‐1aA trans‐continental subgroup. J. Med. Virol. 82:1438–1441, 2010. © 2010 Wiley‐Liss, Inc.
Hydrogen production from a PV/PEM electrolyzer system using a neural‐network‐based MPPT algorithm
Authors: Nafeh Abd El‐Shafy A. 
Published: June 2010

AbstractThe electrolysis of water using a polymer electrolyte membrane (PEM) electrolyzer is a very vital and efficient method of producing hydrogen (H2). The performance of this method can be significantly improved if a photovoltaic (PV) array, with maximum‐power‐point (MPP) tracker, is utilized as an energy source for the electrolyzer. This paper suggests a stand‐alone PV/PEM electrolyzer system to produce pure hydrogen. The paper also develops the different mathematical models for each constituent subsystem. Moreover, the paper develops the suitable maximum‐power‐point tracking (MPPT) algorithm that is based on utilizing the neural network. This algorithm is utilized together with the action of the PI controller to improve the performance of the suggested stand‐alone PV/PEM electrolyzer system through maximizing the hydrogen production rate for every instant. Finally, the suggested hydrogen production system is simulated using the Matlab/Simulink and neural network toolbox. The simulation results of the system indicate the improved relative performance of the suggested hydrogen production system compared with the traditional case of direct connection between the PV array and the PEM electrolyzer. Copyright © 2010 John Wiley & Sons, Ltd.