bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood‐oxygen level dependent MRI measures of cerebrovascular reactivity using a controlled respiratory challenge: Reproducibility and gender differences
Authors: Kassner Andrea , Winter Jeff D. , Poublanc Julien , Mikulis David J. , Crawley Adrian P.
Published: January 2010

Purpose:

To evaluate the reproducibility and gender differences in cerebrovascular reactivity (CVR) measurements obtained using the blood‐oxygen level dependent (BOLD) response to controlled changes in end‐tidal partial pressure of carbon dioxide (PETCO2).

Materials and Methods:

We obtained ethical approval to image 19 healthy volunteers (10 men, 9 women) on a 1.5 Tesla (T) MRI scanner twice on two separate days using identical procedures. CVR images were generated by collecting BOLD MRI data during controlled changes in PETCO2 induced by a sequential gas delivery system.

Results:

Using the intraclass correlation coefficient (ICC), we demonstrated excellent within‐day CVR measures in gray matter (GM) (ICC = 0.92) and white matter (WM) (ICC = 0.88) regions, excellent between‐day reproducibility in GM (ICC = 0.81), and good between‐day reproducibility in the WM (ICC = 0.66). CVR values between men and women were significantly different in the GM and WM. Men exhibited a 22 ± 2% greater CVR in GM and a 17 ± 2% greater CVR in WM compared with females.

Conclusion:

Our results demonstrate the reliability of BOLD MRI CVR measurements obtained using a controlled cerebrovascular challenge. Using this technique, we also revealed significantly increased BOLD response to CO2 in males compared with females. J. Magn. Reson. Imaging 2010; 31: 298–304. © 2010 Wiley‐Liss, Inc.
Diffusion tensor MRI: Preliminary anisotropy measures and mapping of breast tumors
Authors: Partridge Savannah C. , Ziadloo Ali , Murthy Revathi , White Steven W. , Peacock Sue , Eby Peter R. , DeMartini Wendy B. , Lehman Constance D.
Published: January 2010

Purpose:

To investigate whether diffusion tensor imaging (DTI) measures of anisotropy in breast tumors are different from normal breast tissue and can improve the discrimination between benign and malignant lesions.

Materials and Methods:

The study included 81 women with 105 breast lesions (76 malignant, 29 benign). DTI was performed during breast MRI examinations, and fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured for breast lesions and normal tissue in each subject. FA and ADC were compared between cancers, benign lesions, and normal tissue by univariate and multivariate analyses.

Results:

The FA of carcinomas (mean ± SD: 0.24 ± 0.07) was significantly lower than normal breast tissue in the same subjects (0.29 ± 0.07; P < 0.0001). Multiple logistic regression showed that FA and ADC were each independent discriminators of malignancy (P < 0.0001), and that FA improved discrimination between cancer and normal tissue over ADC alone. However, there was no difference in FA between malignant and benign lesions (P = 0.98).

Conclusion:

Diffusion anisotropy is significantly lower in breast cancers than normal tissue, which may reflect alterations in tissue organization. Our preliminary results suggest that FA adds incremental value over ADC alone for discriminating malignant from normal tissue but does not help with distinguishing benign from malignant lesions. J. Magn. Reson. Imaging 2010; 31: 339–347. © 2010 Wiley‐Liss, Inc.
Visualization of deep veins and detection of deep vein thrombosis (DVT) with balanced turbo field echo (b‐TFE) and contrast‐enhanced T1 fast field echo (CE‐FFE) using a blood pool agent (BPA)
Authors: Enden Tone , Storås Tryggve H. , Negård Anne , Haig Ylva , Sandvik Leiv , Gjesdal Kjell‐Inge , Sandset Per Morten , Kløw Nils‐Einar
Published: January 2010

Purpose:

To assess image quality, vessel visualization, preliminary diagnostic properties, and interobserver variability of a novel balanced turbo field echo (b‐TFE) sequence and contrast‐enhanced T1 fast field echo (CE‐FFE) sequence with blood pool agent (BPA).

Materials and Methods:

A total of 15 healthy volunteers and six patients with ultrasound‐verified proximal deep vein thrombosis (DVT) were examined from the inferior vena cava (IVC) to the proximal calf veins.

Results:

The great majority of deep veins were completely visualized on both sequences. In healthy volunteers the IVC was completely visualized in five b‐TFE and 11 CE‐FFE scans, and partially in seven b‐TFE and four CE‐FFE scans (P = 0.008). Poorest image quality was in the pelvis. Contrast‐to‐noise ratio (CNR) was higher on b‐TFE compared to CE‐FFE, with significant difference in calf images (P = 0.036). Sensitivity was 100% for proximal DVT with both methods. Specificity was 70% (CE‐FFE) and 80% (b‐TFE) for proximal femoral DVT; 100% in distal femoral. Interobserver reliability was kappa 1.0 (b‐TFE), 0.9 (CE‐FFE) for proximal, and overall poor for distal DVT.

Conclusion:

Contrast‐enhancement did not add valuable information in visualizing deep veins of the lower limbs compared to b‐TFE, though the IVC was slightly better visualized. Diagnostic properties and interobserver reliability of both sequences were good for proximal DVT and poor for distal DVT. J. Magn. Reson. Imaging 2010; 31: 416–424. © 2010 Wiley‐Liss, Inc.
Diagnostic value of T2‐weighted imaging for the detection of superficial cranial artery inflammation in giant cell arteritis
Authors: Geiger Julia , Bley Thorsten , Uhl Markus , Frydrychowicz Alex , Langer Mathias , Markl Michael
Published: January 2010

Purpose:

To evaluate the diagnostic value of T2‐weighted radial MR imaging for the detection of superficial cranial arteries' inflammatory involvement in patients with giant cell arteritis (GCA).

Materials and Methods:

Forty‐three patients with suspected giant cell arteritis underwent 3 Tesla (T) high‐field MRI. T2‐weighted inversion recovery (IR) fast spin echo images with radial sampling (BLADE‐technique) were acquired and compared with postcontrast T1‐weighted spin echo images.

Results:

T2‐weighted images revealed mural edema in the superficial cranial arteries in 11 patients in concordance with severe inflammatory contrast enhancement in T1‐weighted images (grade 4 in a 4‐point ranking scale). Excellent correlation (r = 0.82; P < 0.001) of measured wall thickness in T1‐ and T2‐weighted images was achieved.

Conclusion:

The results of this study indicate the potential of radial T2 weighted imaging for a first detection of inflammatory changes in the small superficial cranial arteries without the need for contrast medium. Future studies are needed to evaluate the influence of spatial resolution of the T2 images and to improve the detection of moderate GCA related changes in vessel inflammation. J. Magn. Reson. Imaging 2010; 31: 470–474. © 2010 Wiley‐Liss, Inc.
Overlap syndrome of autoimmune chronic liver diseases: MRI findings
Authors: Hyslop W. Brian , Kierans Andrea S. , Leonardou Polytimi , Fritchie Karen , Darling Jama , Elazazzi Mohamed , Semelka Richard C.
Published: January 2010

Purpose:

To describe the MR findings of overlap syndromes of autoimmune chronic liver diseases.

Methods:

Review of clinical and radiological databases between March 2001 and July 2008 for patients with a clinical diagnosis and liver biopsy features compatible with overlap syndrome who had also undergone an abdominal MRI yielded 15 adult patients. MR features of overlap syndrome were reviewed by two radiologists by consensus. Two radiologists independently reviewed the studies in a blinded fashion for primary sclerosing cholangitis (PSC)‐type or non‐PSC‐type features to assess interobserver agreement.

Results:

PSC‐type and non‐PSC‐type overlap syndrome had distinctive MR features. In the consensus review, all 12 patients with PSC‐type overlap syndrome were correctly identified. Imaging findings included central macroregeneration (N = 9), peripheral atrophy (N = 7), biliary duct beading (N = 12), biliary dilation (N = 10), or a combination of all four findings (N = 7). The presence of any of the first three features had 100% specificity for a PSC‐type overlap syndrome. Patients with non‐PSC‐type overlap (N = 3) showed relatively normal liver morphology (N = 3) and minimal biliary ductal dilatation in one patient. There was good interobserver agreement (kappa = 0.76).

Conclusion:

Patients with serologic or pathologic evidence of AIH or PBC with imaging features of PSC may have PSC‐type overlap syndrome. J. Magn. Reson. Imaging 2010; 31: 383–389. © 2010 Wiley‐Liss, Inc.
T1‐weighted–SPACE dark blood whole body magnetic resonance angiography (DB‐WBMRA): Initial experience
Authors: Mihai Georgeta , Chung Yiu‐Cho , Merchant Ali , Simonetti Orlando P. , Rajagopalan Sanjay
Published: January 2010

Purpose:

To evaluate the feasibility of the dark blood fast spin echo (FSE) T1‐weighted–Sampling Perfection with Application of optimized Contrasts using different flip angle Evolution (T1w‐SPACE) sequence in assessing whole body arterial wall information from the extracranial carotids to the popliteal artery.

Materials and Methods:

Twenty‐eight subjects were subjected to noncontrast, dark blood whole body magnetic resonance angiography (DB‐WBMRA) using a T1w‐SPACE sequence optimized for each of the individual stations: carotid artery, thoracic aorta, abdominal aorta, and thigh/superficial femoral artery (SFA). Image quality/vessel wall visualization and the time required to image the four stations were evaluated. Two observers checked the reproducibility of vessel wall depiction by performing quantitative measurements in registered initial and repeat studies (six subjects) of vessel wall and lumen area at 17 locations along the arterial tree.

Results:

In 25 of the 28 scanned subjects, dark blood arterial images acquired in approximately 1 hour total imaging time allowed whole body arterial vessel wall visualization. Quantitative measurements showed high correlation between the initial and repeat studies for each of the observers as well as high interobserver reproducibility (r > 0.95; P < 0.01).

Conclusion:

DB‐WBMRA using T1w‐SPACE is feasible and can be performed with a high degree of reliability. J. Magn. Reson. Imaging 2010; 31: 502–509. © 2010 Wiley‐Liss, Inc.
MRI assessment of pacing induced ventricular dyssynchrony in an isolated human heart
Authors: Eggen Michael D. , Bateman Michael G. , Rolfes Christopher D. , Howard Stephen A. , Swingen Cory M. , Iaizzo Paul A.
Published: January 2010

This study demonstrates the capabilities of MRI in the assessment of cardiac pacing induced ventricular dyssynchrony, and the findings support the need for employing more physiological pacing. A human donor heart deemed non‐viable for transplantation, was reanimated using an MR compatible, four‐chamber working perfusion system. The heart was imaged using a 1.5T MR scanner while being paced from the right ventricular apex (RVA) via an epicardial placed lead. Four‐chamber, short‐axis, and tagged short‐axis cines were acquired in order to track wall motion and intramyocardial strain during pacing. The results of this study revealed that the activation patterns of the left ventricle (LV) during RVA pacing demonstrated intraventricular dyssynchrony; as the left ventricular mechanical activation proceeded from the septum and anterior wall to the lateral wall, with the posterior wall being activated last. As such, the time difference to peak contraction between the septum and lateral wall was ∼125 msec. Likewise, interventricular dyssynchrony was demonstrated from the four‐chamber cine as the time difference between the peak LV and RV free wall motion was 180 msec. With the ongoing development of MR safe and MR compatible pacing systems, we can expect MRI to be added to the list of imaging modalities used to optimize cardiac resynchronization therapy (CRT) and/or alternate site pacing. J. Magn. Reson. Imaging 2010; 31: 466–469. © 2010 Wiley‐Liss, Inc.
Improved fat–water reconstruction algorithm with graphics hardware acceleration
Authors: Johnson David H. , Narayan Sreenath , Flask Chris A. , Wilson David L.
Published: January 2010

Purpose:

To develop a fast and robust Iterative Decomposition of water and fat with Echo Asymmetry and Least‐squares (IDEAL) reconstruction algorithm using graphics processor unit (GPU) computation.

Materials and Methods:

The fat–water reconstruction was expedited by vectorizing the fat–water parameter estimation, which was implemented on a graphics card to evaluate potential speed increases due to data‐parallelization. In addition, we vectorized and compared Brent's method with golden section search for the optimization of the unknown field inhomogeneity parameter (ψ) in the IDEAL equations. The algorithm was made more robust to fat–water ambiguities using a modified planar extrapolation (MPE) of ψ algorithm. As compared to simple planar extrapolation (PE), the use of an averaging filter in MPE made the reconstruction more robust to neighborhoods poorly fit by a two‐dimensional plane.

Results:

Fat–water reconstruction time was reduced by up to a factor of 11.6 on a GPU as compared to CPU‐only reconstruction. The MPE algorithms incorrectly assigned fewer pixels than PE using careful manual correction as a gold standard (0.7% versus 4.5%; P < 10−4). Brent's method used fewer iterations than golden section search in the vast majority of pixels (6.8 ± 1.5 versus 9.6 ± 1.6 iterations).

Conclusion:

Data sets acquired on a high field scanner can be quickly and robustly reconstructed using our algorithm. A GPU implementation results in significant time savings, which will become increasingly important with the trend toward high resolution mouse and human imaging. J. Magn. Reson. Imaging 2010; 31: 457–465. © 2010 Wiley‐Liss, Inc.
Study of the features of proton MR spectroscopy (1H‐MRS) on amyotrophic lateral sclerosis
Authors: Han Jing , Ma Lin
Published: January 2010

Purpose:

To study the features of proton magnetic resonance spectroscopy (1H‐MRS) on amyotrophic lateral sclerosis (ALS) and its relation with clinical scale.

Materials and Methods:

Fifteen patients with definite or probable ALS and 15 age‐ and gender‐matched normal controls were enrolled. 1H‐MRS was performed on a 3.0 Tesla GE imaging system (GE Healthcare, Milwaukee, WI). TE‐averaged Point Resolved Selective Spectroscopy was used. N‐acetylaspartate (NAA), creatine (Cr), Glu, and Glx (glutamate + glutamine) values of the motor cortex and posterior limb of internal capsule were acquired. The t‐test was used to compare differences between groups, and the correlations between the above values and clinical scale were analyzed.

Results:

The motor area and posterior limb of the internal capsule of ALS patients had lower NAA/Cr (1.91 ± 0.34, 1.53 ± 0.17) compared with normal subjects (2.23 ± 0.33, 1.66 ± 0.07), and the differences between groups were statistically significant (P < 0.01, 0.01). ALS patients had higher Glu/Cr (0.34 ± 0.05, 0.29 ± 0.06) and Glx/Cr (0.40 ± 0.04, 0.33 ± 0.06) compared with normal subjects (0.30 ± 0.03, 0.25 ± 0.04) and (0.32 ± 0.05, 0.26 ± 0.03), and the differences between groups were statistically significant (P < 0.01, 0.01). The Norris scale was negatively correlated with Glx/Cr of primary motor cortex by lineal correlation analysis (r = −0.75), and this correlation had statistical significance (F = 16.60; P = 0.001).

Conclusion:

Neuronal loss and Glu+Gln increase can be detected by using proton MRS in ALS patients. 1H‐MRS is an useful tool in reflecting the characteristic changes of metabolite in ALS. J. Magn. Reson. Imaging 2010; 31: 457–465. © 2010 Wiley‐Liss, Inc.
Enhancement of liver parenchyma after injection of hepatocyte‐specific MRI contrast media: A comparison of gadoxetic acid and gadobenate dimeglumine
Authors: Filippone Antonella , Blakeborough Anthony , Breuer Josy , Grazioli Luigi , Gschwend Simone , Hammerstingl Renate , Heinz‐Peer Gertraud , Kittner Thomas , Laghi Andrea , Leen Edward , Lencioni Riccardo , Lucidarme Olivier , Remplik Philipp , Robinson Philip J. , Ruehm Stefan G. , Schaefer Fritz , Stoupis Christoforos , Tombach Bernd , Valette Pierre‐Jean , Zech Christoph J. , Huppertz Alexander
Published: January 2010

Purpose:

To compare enhancement of liver parenchyma in MR imaging after injection of hepatocyte‐specific contrast media.

Materials and Methods:

Patients (n = 295) with known/suspected focal liver lesions randomly received 0.025 mmol gadoxetic acid/kg body weight or 0.05 mmol gadobenate dimeglumine/kg body weight by means of bolus injection. MR imaging was performed before and immediately after injection, and in the delayed phase at approved time points (20 min after injection of gadoxetic acid and 40 min after injection of gadobenate dimeglumine). The relative liver enhancement for the overall population and a cirrhotic subgroup was compared in T1‐weighted GRE sequences. An independent radiologist performed signal intensity measurements. Enhancement ratios were compared using confidence intervals (CIs).

Results:

The relative liver enhancement in the overall population was superior with gadoxetic acid (57.24%) versus gadobenate dimeglumine (32.77%) in the delayed‐imaging phase. The enhancement ratio between the contrast media was statistically significant at 1.75 (95% CI: 1.46–2.13). In the delayed phase, the enhancement of cirrhotic liver with gadoxetic acid (57.00%) was comparable to that in the overall population. Enhancement with gadobenate dimeglumine was inferior in cirrhotic liver parenchyma (26.85%).

Conclusion:

In the delayed, hepatocyte‐specific phase, liver enhancement after injection of gadoxetic acid was superior to that obtained with gadobenate dimeglumine. J. Magn. Reson. Imaging 2010; 31: 356–364. © 2010 Wiley‐Liss, Inc.
Quantifying in vivo hemodynamic response to exercise in patients with intermittent claudication and abdominal aortic aneurysms using cine phase‐contrast MRI
Authors: Tenforde Adam S. , Cheng Christopher P. , Suh Ga‐Young , Herfkens Robert J. , Dalman Ronald L. , Taylor Charles A.
Published: January 2010

Purpose:

To evaluate rest and exercise hemodynamics in patients with abdominal aortic aneurysms (AAA) and peripheral occlusive disease (claudicants) using phase‐contrast MRI.

Materials and Methods:

Blood velocities were acquired by means of cardiac‐gated cine phase‐contrast in a 0.5 Tesla (T) open MRI. Volumetric flow was calculated at the supraceliac (SC), infrarenal (IR), and mid‐aneurysm (MA) levels during rest and upright cycling exercise using an MR‐compatible exercise cycle.

Results:

Mean blood flow increased during exercise (AAA: 130%, Claudicants: 136% of resting heart rate) at the SC and IR levels for AAA participants (2.6 ± 0.6 versus 5.8 ± 1.6 L/min, P < 0.001 and 0.8 ± 0.4 versus 5.1 ± 1.7 L/min, P < 0.001) and claudicants (2.3 ± 0.5 versus 4.5 ± 0.9 L/min, P < 0.005 and 0.8 ± 0.2 versus 3.3 ± 0.9 L/min, P < 0.005). AAA participants had a significant decrease in renal and digestive blood flow from rest to exercise (1.8 ± 0.7 to 0.7 ± 0.6 L/min, P < 0.01). The decrease in renal and digestive blood flow during exercise correlated with daily activity level for claudicants (R = 0.81).

Conclusion:

Abdominal aortic hemodynamic changes due to lower extremity exercise can be quantified in patients with AAA and claudication using PC‐MRI. The redistribution of blood flow during exercise was significant and different between the two disease states. J. Magn. Reson. Imaging 2010; 31: 425–429. © 2010 Wiley‐Liss, Inc.
Comparison of two different injection rates of gadoxetic acid for arterial phase MRI of the liver
Authors: Chung Sang‐Hoon , Kim Myeong‐Jin , Choi Jin‐Young , Hong Hye‐Suk
Published: January 2010

Purpose:

To compare two different injection rates for gadoxetic acid‐enhanced hepatic arterial phase images on hepatic dynamic MRI.

Materials and Methods:

Hepatic arterial phase images were obtained after an intravenous bolus injection of gadoxetic acid at a rate of 1 mL/second in 62 patients and 2 mL/second in 64 patients on a 3 Tesla MR scanner using a test‐bolus injection method. The signal‐to‐noise ratios (SNR) of the liver, portal vein, hepatic vein, aorta, spleen and pancreas were measured. The contrast‐to‐noise ratio (CNR) of hypervascular hepatic tumors was calculated. Two radiologists independently scored items to evaluate image quality of hepatic arterial phase and detected hypervascular hepatocellular carcinoma (HCC).

Results:

The SNR of the aorta on the arterial phase images was significantly higher in the 1 mL/second group (235.43 ± 82.59) than in the 2 mL/second group (190.94 ± 96.90, P < 0.05). The SNRs of the liver, spleen and pancreas, the CNRs of hypervascular hepatic tumors, the detection rate of hypervascular HCC and subjective ratings for the optimal arterial enhancement were comparable between the two groups.

Conclusion:

Injection rates of 2 mL/second and 1 mL/second provided comparable image qualities on arterial phase images of hepatic dynamic MRI using gadoxetic acid. J. Magn. Reson. Imaging 2010; 31: 365–372. © 2010 Wiley‐Liss, Inc.
Detection of hepatocellular carcinoma (HCC) using super paramagnetic iron oxide (SPIO)‐enhanced MRI: Added value of diffusion‐weighted imaging (DWI)
Authors: Nishie Akihiro , Tajima Tsuyoshi , Ishigami Kousei , Ushijima Yasuhiro , Okamoto Daisuke , Hirakawa Masakazu , Nishihara Yunosuke , Taketomi Akinobu , Hatakenaka Masamitsu , Irie Hiroyuki , Yoshimitsu Kengo , Honda Hiroshi
Published: January 2010

Purpose:

To evaluate whether diffusion‐weighted imaging (DWI) improves the detection of hepatocellular carcinoma (HCC) on super paramagnetic iron oxide (SPIO)‐enhanced MRI.

Materials and Methods:

This retrospective study group consisted of 30 patients with 50 HCC nodules who underwent MRI at 1.5 Tesla. Two combined MR sequence sets were compared for detecting HCC: SPIO‐enhanced MRI (axial T2‐weighted fast spin‐echo (FSE) and T1‐/T2*‐weighted fast field echo (FFE) scanned before and after administration of ferucarbotran) and SPIO‐enhanced MRI + DWI (SPIO‐enhanced MRI with axial DWI scanned before and after administration of ferucarbotran). Three blinded readers independently reviewed for the presence of HCC on a segment‐by‐segment basis using a four‐point confidence scale. The performance of the two combined MR sequence sets was evaluated using receiver operating characteristic (ROC) analysis.

Results:

The average area under the ROC curve (Az) of the three readers for the SPIO‐enhanced MRI + DWI set (0.870 ± 0.046) was significantly higher that that for the SPIO‐enhanced MRI set (0.820 ± 0.055) (P = .025). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detection of HCC were 66.0%, 98.0%, 90.0%, and 91.4%, respectively, for the SPIO‐enhanced MRI set, and 70.0%, 98.6%, 92.9%, and 92.4%, respectively, for the SPIO‐enhanced MRI + DWI set.

Conclusion:

The SPIO‐enhanced MRI + DWI set outperformed the SPIO‐enhanced MRI set for depicting HCC. J. Magn. Reson. Imaging 2010; 31: 373–382. © 2010 Wiley‐Liss, Inc.
Two‐point dixon technique provides robust fat suppression for multi‐mouse imaging
Authors: Ragan Dustin K. , Bankson James A.
Published: January 2010

Purpose:

To determine whether Dixon‐based fat separation techniques can provide more robust removal of lipid signals from multiple‐mouse magnetic resonance imaging (MRI)‐acquired images than conventional frequency selective chemical saturation techniques.

Materials and Methods:

A two‐point Dixon technique was implemented using a RARE‐based pulse sequence and techniques for multivolume fat suppression were evaluated using a 4‐element array of volume resonators at 4.7 T. Images were acquired of both phantoms and mice.

Results:

Fat saturation was achieved on all four channels of the multiple mouse acquisition with the Dixon technique, while failures of fat saturation were found with chemical saturation techniques.

Conclusion:

This proof of concept study found that Dixon fat separation provided more reliable and homogenous fat suppression than chemical saturation in phantoms and in vivo. J. Magn. Reson. Imaging 2010; 31:510–514. © 2010 Wiley‐Liss, Inc.
Relationships of brain white matter microstructure with clinical and MR measures in relapsing‐remitting multiple sclerosis
Authors: Giorgio Antonio , Palace Jacqueline , Johansen‐Berg Heidi , Smith Stephen M. , Ropele Stefan , Fuchs Siegrid , Wallner‐Blazek Mirja , Enzinger Christian , Fazekas Franz
Published: January 2010

Purpose:

To assess the relationships of microstructural damage in the cerebral white matter (WM), as measured by diffusion tensor imaging (DTI), with clinical parameters and magnetic resonance imaging (MRI) measures of focal tissue damage in patients with multiple sclerosis (MS).

Materials and Methods:

Forty‐five relapsing‐remitting (RR) MS patients (12 male, 33 female; median age = 29 years, Expanded Disability Status Scale (EDSS) = 1.5, disease duration = 3 years) were studied. T2‐lesion masks were created and voxelwise DTI analyses performed with Tract‐Based Spatial Statistics (TBSS).

Results:

T2‐lesion volume (T2‐LV) was significantly (P < 0.05, corrected) correlated with fractional anisotropy (FA) in both lesions and normal‐appearing WM (NAWM). Relationships (P = 0.08, corrected) between increasing EDSS score and decreasing FA were found in the splenium of the corpus callosum (sCC) and along the pyramidal tract (PY). All FA associations were driven by changes in the perpendicular (to primary tract direction) diffusivity. No significant global and voxelwise FA changes were found over a 2‐year follow‐up.

Conclusion:

FA changes related to clinical disability in RR‐MS patients with minor clinical disability are localized to specific WM tracts such as the sCC and PY and are driven by changes in perpendicular diffusivity both within lesions and NAWM. Longitudinal DTI measurements do not seem able to chart the early disease course in the WM of MS patients. Imaging 2010; 31:309–316. © 2010 Wiley‐Liss, Inc.
Spatial variations of climate indices in Turkey
Authors: Deniz A. , Toros H. , Incecik S.
Published: January 2010

The present study explores the spatial variability of the continentality, oceanity and aridity indices in Turkey. Climatic indices are diagnostic tools used to describe climatic conditions and the state of a climate system. In this study, four indices were calculated using the climatic data from 229 meteorological stations in Turkey. The nature of the indices expresses general climatic features such as continentality, marine influences and aridity. The climatic indices used here are the Johansson Continentality (JC) Index, the Kerner Oceanity Index (KOI), the De Martonne Aridity Index (IDM) and the Pinna Combinative (PV) Index. Furthermore, aridity characteristics in Turkey have been examined using the two separate periods (1960–1990 and 1991–2006). To assess the temperature and precipitation patterns in Turkey, the climatic indices were calculated by using monthly temperature and precipitation for the period 1960–2006. According to the results of the KOI, marine climates characteristics were dominant in the Black Sea region than in its Aegean and Mediterranean region. The JC index is used for the climatic classification between continental and oceanic climates. The continental effect was found across 25% of the country. The maximum continentality with a score of 71.5 has been found in the eastern Anatolia. Furthermore, semi‐dry areas were increasing in the 1991–2006 period compared to 1960–1990. A significant correlation was found between the values of the JC index and the KOI. The JC index gives reasonable results for Turkey. The continental effect was found across 25% of the country. This analysis may be of benefit for the explanation of landscape characteristics and the rational utilization of water resources, agriculture and energy scenarios for the region in many areas of Turkey. Copyright © 2010 Royal Meteorological Society
Electrospun Silk Material Systems for Wound Healing
Authors: Wharram Scott E. , Zhang Xiaohui , Kaplan David L. , McCarthy Stephen P.
Published: January 2010

The functional properties of six distinct electrospun silk material groups were evaluated to assess conformational and biocompatible characteristics related to wound dressings. In a hydrated state, all six silk matrices exhibited absorption, water vapor transmission, oxygen permeation and enzymatic biodegradation suitable for full‐thickness wound sites. Employing constrained drying techniques, silk concentration was a determinate factor influencing material structural properties related to the storage and distribution of such wound dressing systems. Subsequently, three electrospun silk models demonstrated ideal biomaterial properties with potential utility for wound dressings.

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Regularity of harmonic functions for anisotropic fractional Laplacians
Authors: Sztonyk Paweł
Published: January 2010

We prove that bounded harmonic functions of anisotropic fractional Laplacians are Hölder continuous under mild regularity assumptions on the corresponding Lévy measure. Under some stronger assumptions the Green function, Poisson kernel and the harmonic functions are even differentiable of order up to three (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observations on Solution Crystallization of Poly(vinyl alcohol) in the Presence of Single‐Wall Carbon Nanotubes
Authors: Minus Marilyn L. , Chae Han Gi , Kumar Satish
Published: January 2010

PVA/SWNT dispersions yield aloe plant‐like crystals, where the leaves are single crystals templated by PVA coated SWNT. Longer growth times (≈18 months) lead to hexagonal rod‐like crystals. HR‐TEM images show evidence that PVA molecules are aligned parallel to the SWNT axis. WAXD, electron diffraction, and HR‐TEM observations of these aloe plant and hexagonal crystals suggests evidence for possible PVA‐SWNT epitaxy. Wide‐angle and electron diffraction data of these crystals also show that the structure seems to mimic the 2D hexagonal crystal packing of SWNT. PVA lattice images and moiré fringes were also observed in the leaf‐like crystals.

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Generalizing link prediction: Collaboration at the University of Antwerp as a case study
Authors: Guns Raf
Published: January 2010

The link prediction (LP) approach tries to predict links in an unknown network on the basis of a known network. It is argued that LP evaluation can be treated analogous to Information Retrieval evaluation. This characterization entails three generalizations of LP: both appearing and disappearing links can be predicted, LP is not necessarily time‐based, and LP is complementary to anomalous link and gap discovery. Multi‐input LP tries to increase precision and recall by having more than one known network as input. These concepts are applied to an informetric case study of collaboration at the University of Antwerp. Performance of different prediction methods is discussed. Furthermore, we establish a small but positive influence for multi‐input LP.
Information in action: A situated view
Authors: Ekbia Hamid
Published: January 2010

The role of information in daily activities is a key question for information science. Various theories and approaches have been developed to conceptualize the objects and events that inform people as they go about the conduct of daily life. This paper introduces the notion of ‘regimes of information’ to account for the different shapes and meanings that information takes in various situations. Building on Buckland (1991)'s account, and adopting the situated perspective of Garfinkel (2008), the paper applies Boltanski and Thévenot (2006)'s polity model to define and develop the notion of regimes of information. I argue that rather than ‘using’ information as a given, people enact it variously depending on the kind of situation in which they find themselves.
Providing support for multi‐session web tasks
Authors: MacKay Bonnie , Watters Carolyn
Published: January 2010

In two previous studies, we explored how users perform multi‐session web tasks (those tasks that require more than one web session to complete). Using the results of these studies, we proposed three guidelines to help developers design browser support for these types of tasks. In this paper, we describe three prototypes that we designed and developed using these guidelines and the results of a preliminary evaluation of the prototypes in the field. We found that while participants found the simplest prototype to be the easiest to use, it was the other two prototypes with additional functionality that were deemed more useful by participants. In addition, participants preferred the prototypes with additional functionality that helped manage their tasks between sessions.
The ICT paradox in Uganda: The convergence of radio and telephony in the power contest between the resurging Buganda Nationalism and the central government
Authors: Muwanguzi Samuel
Published: January 2010

This paper examines the role of information and communication technologies (ICT) in the power contest between the re‐emerging traditionalism and the flagging influence of nationalism in Uganda. The analysis is placed within a globalized information revolution that swept through the African continent resulting in the liberalization of the airwaves and the telephony which effectively ended the monopoly of governments over the primary channels of communication with the population. Specifically, the paper offers an analysis of how the convergence of the Buganda Kingdom FM radio station, the Central Broadcasting Services (CBS) and the now ubiquitous cell phone, have contributed to the resurgence of Buganda nationalism and is leading the kingdom's power contest against the previously all powerful central government over land ownership. Second, the paper presents a brief historical perspective to establish the context and clarify the factors responsible for this power contest between the two previously erstwhile allies. The paper also suggests how the conflict could be resolved and how ICT could be used productively to maximize globalization benefits while minimizing the destabilizations, dislocations, disparities, distortions, and the escalation of disruptions that caused the power contest and threaten to plunge the country into a bloodbath.
Children's strategies in coping with daily life: Does information matter?
Authors: Lu Ya‐Ling
Published: January 2010

This article offers empirical evidence of children's information behaviors in coping with daily life experiences. One hundred thirty‐three children in Taiwan, ages 11 and 12, participated in the study. Each participant kept a semi‐structured journal for four days. The study elicited five different information behaviors related to coping:Information Seeking for Problem Solving; Information Seeking for Problem Analysis; Information Use for Escape; Information Use for a Transition;andInformation Avoidance. This is an exploratory study, but it provides insights into issues related to children's information behaviors and information services in a coping context.
Practicing place: Collective experience and difference in an urban online forum
Authors: Walker Dana , Wehner Patrick
Published: January 2010

Despite predictions to the contrary, place has assumed a new significance through recent innovations in digital technology. In this paper, we argue that the exchange of information and experience occurring daily on the networked urban forum Phillyblog can be usefully conceptualized as the practice of place. In adopting this terminology, we suggest particular analytic and theoretical lines which hold important implications for the way we think about information and place in online settings. Within the context of Phillyblog, the practice of place (1) publicizes and reinforces collective experiences of the city and (2) plays an active role in constructing the distinctness and diversity of its neighborhoods. In analyzing their regular interactions on Phillyblog, we hope to add to research on information practice, in particular “everyday information practices” (Savolainen, 2008), by suggesting their role in the social construction of place. Using this particular case, we explore how information sharing and production, in particular, may play a role in the perception, conception, and experience of place.
Searching with tags: Do tags help users find things?
Authors: Kipp Margaret E.I.
Published: January 2010

This study examines the question of whether tags can be useful in the process of information retrieval. Participants were asked to search a social bookmarking tool specialising in academic articles (CiteULike) and an online journal database (PubMed) in order to determine if users found tags were useful in their search process. The actions of each participants were captured using screen capture software and they were asked to describe their search process. The preliminary study showed that users did indeed make use of tags in their search process, as a guide to searching and as hyperlinks to potentially useful articles. However, users also made use of controlled vocabularies in the journal database to locate useful search terms and of links to related articles supplied by the database.
Discourse analysis of online chat reference interviews for modeling online information‐seeking dialogues
Authors: Inoue Keisuke
Published: January 2010

Recent developments in Web technologies have enabled a rapid increase in computer‐mediated information‐seeking communications. This manuscript presents the dissertation research the author is undertaking, which will involve a discourse analysis of online chat reference dialogues. The goal of the study is to examine existing information seeking behavior models in the recent context of the computer‐mediated communication (CMC), and to augment the theories by developing a dialogue model of information‐seeking CMC. In doing so, the study will develop an annotation scheme by incorporating dialogue act analysis into the analysis of information behavior. The contribution of the study will be to inform the design of information retrieval systems that utilize the CMC as an information resource or incorporate interactive user interface.
Individual differences in source selection behavior: Profile analyses via multidimensional scaling
Authors: Kim Kyung‐Sun , Yoo Eun‐Young , Kwon Nahyun , Sin Sei‐Ching Joanna
Published: January 2010

The study aims to understand how undergraduate students perceive and use different information sources. The study will examine: (1) how students perceive and use different sources, (2) how the perception and the use of information sources are related, and (3) how the user characteristics and source use behaviors are related. Their relationships will be examined through correlations and profile analyses via multidimensional scaling.
Modeling Web search: Preliminary results
Authors: Du Jia Tina , Spink Amanda
Published: January 2010

This paper reports preliminary results from a study modeling the interplay between multitasking, cognitive coordination, and cognitive shifts during Web search. Study participants conducted three Web searches on personal information problems. Data collection techniques included pre‐ and post‐search questionnaires, think‐aloud protocols, Web search logs, observation, and post‐search interviews. Key findings include: (1) users Web searches included multitasking, cognitive shifting and cognitive coordination processes, (2) cognitive coordination is the hinge linking multitasking and cognitive shifting that enables Web search construction, (3) cognitive shift levels determine the process of cognitive coordination, and (4) cognitive coordination is interplay of task, mechanism and strategy levels that underpin multitasking and task switching. An initial model depicts the interplay between multitasking, cognitive coordination, and cognitive shifts during Web search. Implications of the findings and further research are also discussed.
How can academic libraries go beyond e‐Science: The emergence of the new contribution‐recognition system
Authors: Ku Min‐Chun
Published: January 2010

This poster aims at exploring how academic libraries can help shape the development of e‐Science and facilitate scholarship. It first discusses the problems that the e‐Science community is facing. This poster then argues that the issues emerged in the e‐Science practice will drive the need for a new contribution‐recognition system that reflects the accumulative, social and collaborative characteristics of science, and recognizes the values of various types of expertise to e‐Science and human knowledge. Finally, it proposes directions of how academic libraries can actively ground themselves in everyday research practice and shape the e‐Science revolution by providing new research data and information services based on the new contribution‐recognition system that encourages, documents, traces, and recognizes the contribution of different types of participation.
Sign language online: Challenges in creating, posting, and linking to sign language content without text.
Authors: Goodrum Abby , Hibbard Ellen
Published: January 2010

In this paper, we present an overview of the SignLink Studio system, and preliminary results of a study of SignLink Studio with deaf web users. We note the unique semantic challenges of creating non‐textual metadata, and comment upon areas for future research and development.
Multivariate analysis of image search strategies
Authors: Westman Stina , Berg Anna , Oittinen Pirkko
Published: January 2010

This poster reports on a work in progress on the analysis of search strategies of users of an online image database. We combine transaction logging with qualitative query content analysis which enables a rich multivariate analysis of search behavior. The aim is to explore the suitability of transaction log analysis methodology in image retrieval and generate a wider understanding of the uses of image databases to inform system design.
User perspectives on NextGen catalog features
Authors: Salaba Athena , Zhang Yin
Published: January 2010

Since the development of the online public access catalog (OPAC), there has been discussion about what constitutes a next‐generation (NextGen) catalog. In the last few years, many user‐centered features have been included in both vendor and open source NextGen catalogs. What is lacking, though, is a study of user perspectives on the usefulness of these features in searches. Examining these perspectives will provide insight important to future the development of NextGen catalogs. In this study, 98 library science students reviewed the features of the AcquaBrowser, Encore, VuFind, and Scriblio systems. Participants used a 10 point scale (1=low, 10=high) to rate the helpfulness and desirability of user‐centered features such as the simple search box, advanced search options, results sorting options, enriched content, user contributed content, faceted navigation, relevance ranking, spell checking, word constellations, word clouds, recommendations for similar items, external links, and other Web 2.0 features. Overall ratings show the advanced search option to have been the most helpful and the recently added items feature to have been least helpful, while faceted navigation was the most desirable feature and the recently added items feature was the least desirable. For all features included in the study, except the advanced search option, the average desirability of the features was rated higher than the average helpfulness. Additionally, more detailed findings, including users' comments about NextGen catalog features, are reported.
A first order theory of bibliographic objects
Authors: Wickett Karen , Renear Allen
Published: January 2010

We present a characterization of the core entities and relationships of the Functional Requirements for Bibliographic Records (FRBR) in first order logic. Evidence from the text and diagrams in FRBR support the identification of axioms that capture the constraints and assumptions built into the model. The result is an axiomatic system that clarifies the meaning of the specification. This approach provides a more systematic way of clarifying ambiguities and confusions in the interpretation of FRBR than separate analyses of individual problems and allows scholars and system builders concerned with bibliographic theory to clarify their interpretation of the specification prior to the choice of an implementation language, such as RDF or OWL.
Improved SNR in phase contrast velocimetry with five‐point balanced flow encoding
Authors: Johnson Kevin M. , Markl Michael
Published: January 2010

Phase contrast velocimetry can be utilized to measure complex flow for both quantitative and qualitative assessment of vascular hemodynamics. However, phase contrast requires that a maximum measurable velocity be set that balances noise and phase aliasing. To efficiently reduce noise in phase contrast images, several investigators have proposed extended velocity encoding schemes that use extra encodings to unwrap phase aliasing; however, existing techniques can lead to significant increases in echo and scan time, limiting their clinical benefits. In this work, we have developed a novel five‐point velocity encoding scheme that efficiently reduces noise with minimal increases in scan and echo time. Investigations were performed in phantoms, demonstrating a 63% increase in velocity‐to‐noise ratio compared to standard four‐point encoding schemes. Aortic velocity measurements were performed in healthy volunteers, showing similar velocity‐to‐noise ratio improvements. In those volunteers, it was also demonstrated that, without sacrificing accuracy, low‐resolution images can be used for the fifth encoding point, reducing the scan time penalty from 25% down to less than 1%. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Asymmetries of the balanced SSFP profile. Part I: Theory and observation
Authors: Miller Karla L.
Published: January 2010

The signal in balanced steady‐state free precession has a strong sensitivity to off‐resonance, which is typically described in terms of a signal “profile” over a range of frequencies. This profile has a well‐known form for homogeneous media with a single T1, T2, and resonance frequency, which is symmetric about the on‐resonance frequency. However, a straightforward extension to this established signal model predicts that the profile may become asymmetric in the presence of inhomogeneous frequency content, as would be expected to happen in tissue due to microstructural boundaries, compartments, and chemical shift. The presence of asymmetries in the balanced steady‐state free precession profile may therefore provide a marker of tissue integrity. This manuscript describes the theory behind balanced steady‐state free precession asymmetries, a method for detecting these effects, and the first measurements of balanced steady‐state free precession asymmetries in tissue. Asymmetries are found in gray matter, white matter, and muscle, with excellent reproducibility. A companion paper considers the large white matter asymmetries in more detail. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.