NMR in BiomedicineThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

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Reproducibility of tract-specific magnetization transfer and diffusion tensor imaging in the cervical spinal cord at 3 teslaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined the variability and interrater and test-retest reliability for each metric. These column-specific MR measurements are expected to enhance understanding of the intimate structure-function relationship in the cervical spinal cord and may be useful for the assessment of disease progression. Copyright © 2009 John Wiley & Sons, Ltd. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 19, 2009 Category: Radiology Authors: Seth A. Smith, Craig K. Jones, Aliya Gifford, Visar Belegu, BettyAnn Chodkowski, Jonathan A. D. Farrell, Bennett A. Landman, Daniel S. Reich, Peter A. Calabresi, John W. McDonald, Peter C.M. van Zijl Source Type: journals

Age-related changes in brain energetics and phospholipid metabolismEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aimed to investigate the relationship of brain energy metabolism to healthy aging by assessing tissue specific differences in metabolites observable by phosphorus (31P) MRS. 31P MRSI at 4 Tesla (T) was performed on 34 volunteers, aged 21-84, screened to exclude serious medical and psychiatric diagnoses. Linear mixed effects models were used to analyze the effects of age on phosphorus metabolite concentrations, intracellular magnesium and pH estimates in brain tissue. A significant age associated decrease in brain pH (-0.53% per decade), increase in PCr (1.1% per decade) and decrease in PME (1.7% per decade) were...
Source: NMR in Biomedicine - November 12, 2009 Category: Radiology Authors: Brent P. Forester, Yosef A. Berlow, David G. Harper, J. Eric Jensen, Nicholas Lange, Michael P. Froimowitz, Caitlin Ravichandran, Dan V. Iosifescu, Scott E. Lukas, Perry F. Renshaw, Bruce M. Cohen Source Type: journals

Quantification of brain glycogen concentration and turnover through localized 13C NMR of both the C1 and C6 resonancesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have recently shown that at isotopic steady state 13C NMR can provide a direct measurement of glycogen concentration changes, but that the turnover of glycogen was not accessible with this protocol. The aim of the present study was to design, implement and apply a novel dual-tracer infusion protocol to simultaneously measure glycogen concentration and turnover. After reaching isotopic steady state for glycogen C1 using [1-13C] glucose administration, [1,6-13C2] glucose was infused such that isotopic steady state was maintained at the C1 position, but the C6 position reflected 13C label incorporation. To overcome the lar...
Source: NMR in Biomedicine - November 11, 2009 Category: Radiology Authors: Ruud B. van Heeswijk, Florence D. Morgenthaler, Lijing Xin, Rolf Gruetter Source Type: journals

Performance evaluation of a 32-element head array with respect to the ultimate intrinsic SNREmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The quality of an RF detector coil design is commonly judged on how it compares with other coil configurations. The aim of this article is to develop a tool for evaluating the absolute performance of RF coil arrays. An algorithm to calculate the ultimate intrinsic signal-to-noise ratio (SNR) was implemented for a spherical geometry. The same imaging tasks modeled in the calculations were reproduced experimentally using a 32-element head array. Coil performance maps were then generated based on the ratio of experimentally measured SNR to the ultimate intrinsic SNR, for different acceleration factors associated with differen...
Source: NMR in Biomedicine - November 11, 2009 Category: Radiology Authors: Riccardo Lattanzi, Aaron K. Grant, Jonathan R. Polimeni, Michael A. Ohliger, Graham C. Wiggins, Lawrence L. Wald, Daniel K. Sodickson Source Type: journals

Metabolic correlatives of brain activity in a FOS epilepsy patientEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study reports findings obtained on a subject suffering from fixation-off sensitivity (FOS) epilepsy, exploited as a model system of triggerable anomalous electrical activity. Functional Magnetic Resonance Spectroscopy was used to investigate the metabolic response to visual spike-inducing stimuli in a single voxel placed in the temporo-occipital lobe of a FOS epilepsy patient. MRS measurements were additionally performed on a control group of five healthy volunteers. The FOS patient also underwent an EEG session with the same stimulus paradigm. Uniquely in the FOS patient, glutamate and glutamine concentration increas...
Source: NMR in Biomedicine - October 17, 2009 Category: Radiology Authors: Stefano Peca, Marco Carnì, Carlo Di Bonaventura, Teresa Aprile, Gisela E. Hagberg, Anna Teresa Giallonardo, Mario Manfredi, Silvia Mangia, Girolamo Garreffa, Bruno Maraviglia, Federico Giove Source Type: journals

Correlation of DTI metrics in the wall and cavity of brain abscess with histology and immunohistochemistryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Diffusion tensor imaging (DTI) was performed in eight patients with brain abscess (BA). The aim of this study was to see the difference in the relationship between intercellular cell adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) expression and DTI metrics measured in vivo in the wall and cavity of BA and its possible explanation vis-à-vis histology and immunohistochemistry. Neuroinflammatory molecules (NMs) were quantified from BA cavity aspirate of the patients and quantitative immunohistochemical analysis was performed for ICAM-1 and LFA-1 in the BA wall, showing maximal positive stai...
Source: NMR in Biomedicine - October 15, 2009 Category: Radiology Authors: Rakesh K. Gupta, Savita Srivastava, Sona Saksena, Ram K. S. Rathore, Rishi Awasthi, Kashi N. Prasad, Mazhar Husain, Chandra M. Pandey, Nuzhat Husain Source Type: journals

Non-invasive detection of glycine as a biomarker of malignancy in childhood brain tumours using in-vivo 1H MRS at 1.5 Tesla confirmed by ex-vivo high-resolution magic-angle spinning NMREmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aimed to investigate the quantitation of Gly in paediatric brain tumours using MRS analysed by LCModelTM, and its potential as a non-invasive biomarker of malignancy. Single-voxel MRS was performed using PRESS (TR 1500 ms, TE 30 ms/135 ms) on a 1.5 T scanner. Forty-seven cases (18 high grade (HG), 17 low grade (LG), 12 ungraded) were retrospectively selected if both short-TE and long-TE MRS (n = 33) or short-TE MRS and high-resolution magic-angle spinning (HRMAS) of matched surgical samples (n = 15) were available. The inclusion of Gly in LCModelTM analyses led to significantly reduced fit residues for both shor...
Source: NMR in Biomedicine - September 30, 2009 Category: Radiology Authors: N. P. Davies, M. Wilson, K. Natarajan, Y. Sun, L. MacPherson, M-A. Brundler, T. N. Arvanitis, R. G. Grundy, A. C. Peet Source Type: journals

Nanoparticle phagocytosis and cellular stress: involvement in cellular imaging and in gene therapy against gliomaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In gene therapy against glioma, targeting tumoral tissue is not an easy task. We used the tumor infiltrating property of microglia in this study. These cells are well adapted to this therapy since they can phagocyte nanoparticles and allow their visualization by MRI. Indeed, while many studies have used transfected microglia containing a suicide gene and other internalized nanoparticles to visualize microglia, none have combined both approaches during gene therapy. Microglia cells were transfected with the TK-GFP gene under the control of the HSP70 promoter. First, the possible cellular stress induced by nanoparticle inter...
Source: NMR in Biomedicine - September 29, 2009 Category: Radiology Authors: Anne-Karine Bouzier-Sore, Emeline Ribot, Véronique Bouchaud, Sylvain Miraux, Etienne Duguet, Stéphane Mornet, Gisèle Clofent-Sanchez, Jean-Michel Franconi, Pierre Voisin Source Type: journals

Correlation of endorectal 2D JPRESS findings with pathological Gleason scores in prostate cancer patientsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
To determine the metabolite ratios of (Cho + Cr)/Cit and (Cho + Cr)/Spm in patients with two ranges of pathological Gleason scores, namely (3 + 4) and (4 + 3). By using the localized two-dimensional (2D) J-resolved spectroscopy (JPRESS) technique, the metabolites ratios can be calculated and correlated with prostate cancer aggressiveness. A total of 24 patients who underwent endorectal 2D JPRESS between April 2006 and July 2007 were included in this study. The 2D JPRESS voxel was localized predominantly in the peripheral zone suspected for malignancy based on pathology. Using the metabolites such as total choline (Cho), cr...
Source: NMR in Biomedicine - September 29, 2009 Category: Radiology Authors: Rajakumar Nagarajan, Ana M. Gomez, Steve S. Raman, Daniel J. Margolis, Tim McClure, M. Albert Thomas Source Type: journals

Non-invasive and quantitative evaluation of peripheral vascular resistances in rats by combined NMR measurements of perfusion and blood pressure using ASL and dynamic angiographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The in vivo determination of peripheral vascular resistances (VR) is crucial for the assessment of arteriolar function. It requires simultaneous determination of organ perfusion (F) and arterial blood pressure (BP). A fully non-invasive method was developed to measure systolic and diastolic BP in the caudal artery of rats based on dynamic NMR angiography. A good agreement was found between the NMR approach and the gold standard techniques (linear regression slope = 0.98, R2 = 0.96). This method and the ASL-MRI measurement of skeletal muscle perfusion were combined into one single NMR experiment to quantitatively evaluate t...
Source: NMR in Biomedicine - September 29, 2009 Category: Radiology Authors: Jacques C. Ménard, Eric Giacomini, Céline Baligand, Yves Fromes, Pierre G. Carlier Source Type: journals

High resolution NMR based analysis of serum lipids in Duchenne muscular dystrophy patients and its possible diagnostic significanceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Proton NMR spectroscopic investigations on the lipid extract of the serum of 41 Duchenne muscular dystrophy (DMD) (age, mean ± SD; 8.0 ± 3.0 years) patients and 22 healthy subjects (age, mean ± SD; 9.0 ± 4.0 years) were performed in the northern Indian population. The concentration of triglycerides, phospholipids, free cholesterol, cholesterol esters and total cholesterol was significantly higher in DMD patients as compared to healthy subjects. Ratio of free-cholesterol to cholesterol-esters was also significantly higher in DMD patients. Among the individual lipids, concentration of phospholipids was found to be consis...
Source: NMR in Biomedicine - September 27, 2009 Category: Radiology Authors: Niraj Kumar Srivastava, Sunil Pradhan, Balraj Mittal, G. A. Nagana Gowda Source Type: journals

Rapid simultaneous acquisition of T1 and T2 mapping images using multishot double spin-echo EPI and automated variations of TR and TE (ms-DSEPI-T12)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A rapid method of simultaneous T1 and T2 measurement is presented which uses a segmented echo-planar readout with varying repetition times (TR) and echo times (TE). This method is useful in T1 mapping for analysis of dynamic contrast enhanced MRI (DCE-MRI), where T1 can be used to estimate contrast agent concentration. In the application of this method to dynamic imaging, the equilibrium magnetization is measured on pre-contrast images and incorporated into post-contrast T1 calculations for improved accuracy. Simultaneous T2 measurement allows correction of T2 effects in the T1 map which may occur at high contrast agent co...
Source: NMR in Biomedicine - September 23, 2009 Category: Radiology Authors: Xin Liu, Yi Feng, Zheng-Rong Lu, Glen Morrell, Eun-Kee Jeong Source Type: journals

In vitro, high-resolution 1H and 31P NMR based analysis of the lipid components in the tissue, serum, and CSF of the patients with primary brain tumors: one possible diagnostic viewEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study suggests the role of lipid estimation in CSF and serum as a complementary diagnostic tool for the evaluation of brain tumors preoperatively. NMR-based lipid estimation of post-surgical tumor tissue may also contribute to differentiating the tumor types. Copyright © 2009 John Wiley & Sons, Ltd. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - September 22, 2009 Category: Radiology Authors: Niraj Kumar Srivastava, Sunil Pradhan, G. A. Nagana Gowda, Raj Kumar Source Type: journals

Reproducibility of serial whole-brain MR Spectroscopic ImagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The reproducibility of serial measurements using a volumetric proton MR Spectroscopic Imaging (MRSI) acquisition implemented at 3 Tesla and with lipid suppression by inversion-recovery has been evaluated. Data were acquired from two subjects at five time points, and processed using fully-automated procedures that included rigid registration between studies. These data were analyzed to determine coefficients of variance (COV) for each metabolite and for metabolite ratio images based on an individual voxel analysis, as well as for average and grey-matter and white-matter values from atlas-defined brain regions. The volumetri...
Source: NMR in Biomedicine - September 22, 2009 Category: Radiology Authors: A. A. Maudsley, C. Domenig, S. Sheriff Source Type: journals

Intravoxel water diffusion heterogeneity imaging of human high-grade gliomasEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aimed to determine the potential value of intravoxel water diffusion heterogeneity imaging for brain tumor characterization and evaluation of high-grade gliomas, by comparing an established heterogeneity index ([alpha] value) measured in human high-grade gliomas to those of normal appearing white and grey matter landmarks. Twenty patients with high-grade gliomas prospectively underwent diffusion-weighted magnetic resonance imaging using multiple b-values. The stretched-exponential model was used to generate [alpha] and distributed diffusion coefficient (DDC) maps. The [alpha] values and DDCs of the tumor and con...
Source: NMR in Biomedicine - September 22, 2009 Category: Radiology Authors: Thomas C. Kwee, Craig J. Galbán, Christina Tsien, Larry Junck, Pia C. Sundgren, Marko K. Ivancevic, Timothy D. Johnson, Charles R. Meyer, Alnawaz Rehemtulla, Brian D. Ross, Thomas L. Chenevert Source Type: journals

The effect of experimental conditions on the detection of spermine in cell extracts and tissuesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aim of this work was to investigate the effect of experimental conditions on the visibility of polyamines. In solution the chemical shift of the three groups of peaks (at approximately 1.8, 2.1 and 3.1 ppm) were found to be pH dependent. Relaxation times in aqueous solution at pH 7.0, 298 K and 11.74 T were measured to be: putrescine (T1 = 2.49 s, T2 = 2.07 s), spermidine (T1 = 1.27 s, T2 = 1.05 s) and spermine (T1 = 1.02 s, T2 = 0.82 s). Simple spin-echo sequences could not be used to measure T2 as the spins also experience phase evolution from homonuclear coupling which imposes a modulation on the T2 decay curve. Thi...
Source: NMR in Biomedicine - September 15, 2009 Category: Radiology Authors: Nicholas G. Spencer, Thomas R. Eykyn, Nandita M. deSouza, Geoffrey S. Payne Source Type: journals

Magnetic resonance spectroscopy of the occipital cortex and the cerebellar vermis distinguishes individual cats affected with alpha-mannosidosis from normal catsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A genetic deficiency of lysosomal alpha-mannosidase causes the lysosomal storage disease alpha-mannosidosis (AMD), in which oligosaccharide accumulation occurs in neurons and glia. The purpose of this study was to evaluate the role of magnetic resonance spectroscopy (MRS) in detecting the oligosaccharide accumulation in AMD. Five cats with AMD and eight age-matched normal cats underwent in vivo MRS studies with a single voxel short echo time (20 ms) STEAM spectroscopy sequence on a 4.7T magnet. Two voxels were studied in each cat, from the cerebellar vermis and the occipital cortex. Metabolites of brain samples from these ...
Source: NMR in Biomedicine - September 8, 2009 Category: Radiology Authors: Sergey Magnitsky, Charles H. Vite, Edward J. Delikatny, Stephen Pickup, Suzanne Wehrli, John H. Wolfe, Harish Poptani Source Type: journals

Complex geometric models of diffusion and relaxation in healthy and damaged white matterEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Which aspects of tissue microstructure affect diffusion weighted MRI signals? Prior models, many of which use Monte-Carlo simulations, have focused on relatively simple models of the cellular microenvironment and have not considered important anatomic details. With the advent of higher-order analysis models for diffusion imaging, such as high angular resolution diffusion imaging (HARDI), more realistic models are necessary. This paper presents and evaluates the reproducibility of simulations of diffusion in complex geometries. Our framework is quantitative, does not require specialized hardware, is easily implemented with ...
Source: NMR in Biomedicine - September 8, 2009 Category: Radiology Authors: Bennett A. Landman, Jonathan A. D. Farrell, Seth A. Smith, Daniel S. Reich, Peter A. Calabresi, Peter C. M. van Zijl Source Type: journals

Magnetic resonance spectroscopy shows an inverse correlation between intramyocellular lipid content in human calf muscle and local glycogen synthesis rateEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we examined whether IMCL content in human calf muscle correlated with local glucose uptake assessed by measurement of glycogen synthesis rate within the same muscle compartment. We studied 20 subjects belonging to four subgroups of five persons each: young lean, elderly lean, young obese and elderly obese. IMCL content in the soleus and gastrocnemius muscle was determined using 1H MR spectroscopic imaging and local glycogen synthesis rate in the calf muscle was measured by 13C MRS during a euglycaemic hyperinsulinaemic clamp with 20% w/v 30% 13C-1-labelled glucose infusion. Significantly higher IMCL contents...
Source: NMR in Biomedicine - September 7, 2009 Category: Radiology Authors: Marinette van der Graaf, Cees J. Tack, Jacco H. de Haan, Dennis W. J. Klomp, Arend Heerschap Source Type: journals

Noise correlations and SNR in phased-array MRSEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The acquisition of magnetic resonance spectroscopy (MRS) signals by multiple receiver coils can improve the signal-to-noise ratio (SNR) or alternatively can reduce the scan time maintaining a reliable SNR. However, using phased array coils in MRS studies requires efficient data processing and data combination techniques in order to exploit the sensitivity improvement of the phased array coil acquisition method. This paper describes a novel method for the combination of MRS signals acquired by phased array coils, even in presence of correlated noise between the acquisition channels. In fact, although it has been shown that ...
Source: NMR in Biomedicine - August 25, 2009 Category: Radiology Authors: N. Martini, M. F. Santarelli, G. Giovannetti, M. Milanesi, D. De Marchi, V. Positano, L. Landini Source Type: journals

NMR-based metabolomic analysis of cerebrospinal fluid and serum in neurological diseases - a diagnostic tool?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We sought to evaluate the diagnostic accuracy of metabolomic biomarker profiles in neurological conditions (idiopathic intracranial hypertension (IIH), multiple sclerosis (MS) and cerebrovascular disease (CVD) compared to controls with either no neurological disease or mixed neurological diseases).Spectra of CSF (n = 87) and serum (n = 72) were acquired using 1H NMR spectroscopy. Multivariate pattern recognition analysis was used to identify disease-specific metabolite biomarker profiles. The metabolite profiles were then used to predict the diagnosis of a second cohort of patients (n = 25). CSF metabolite profiles were ab...
Source: NMR in Biomedicine - August 17, 2009 Category: Radiology Authors: Alexandra J. Sinclair, Mark R. Viant, Alexandra K. Ball, Michael A. Burdon, Elizabeth A. Walker, Paul M. Stewart, Saaeha Rauz, Stephen P. Young Source Type: journals

Difference spectroscopy using PRESS asymmetry: application to glutamate, glutamine, and myo-inositolEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A simple, clinically viable technique utilizing PRESS and strong coupling properties is presented for discrimination of coupled brain metabolites. The method relies on signal variation due to alteration of inter-echo timings (PRESS asymmetry) while maintaining a constant total echo time. Spin response of singlets and weakly coupled spins is unchanged due to PRESS asymmetry, allowing difference spectroscopy to detect unobstructed strongly coupled resonances. No changes to the standard PRESS sequence are required except variation of inter-echo timings. The procedure is illustrated for the separate detection of glutamate from...
Source: NMR in Biomedicine - August 17, 2009 Category: Radiology Authors: Jeff Snyder, Richard B. Thompson, Alan H. Wilman Source Type: journals

1H-MRSI pattern perturbation in a mouse glioma: the effects of acute hyperglycemia and moderate hypothermiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
MR spectroscopic Imaging (MRSI), with PRESS localization, is used here to monitor the effects of acute hyperglycemia in the spectral pattern of 11 mice bearing GL261 gliomas at normothermia (36.5-37.5°C) and at hypothermia (28.5-29.5°C). These in vivo studies were complemented by ex vivo high resolution magic angle spinning (HR-MAS) analysis of GL261 tumor samples from 6 animals sacrificed by focused microwave irradiation, and blood glucose measurements in 12 control mice. Apparent glucose levels, monitored by in vivo MRSI in brain tumors during acute hyperglycemia, rose to an average of 1.6-fold during hypothermia (p < ...
Source: NMR in Biomedicine - August 7, 2009 Category: Radiology Authors: R.V. Simões, T. Delgado-Goñi, S. Lope-Piedrafita, C. Arús Source Type: journals

Noninvasive quantification of human brain ascorbate concentration using 1H NMR spectroscopy at 7 TEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ascorbate (Asc, vitamin C) was quantified in the human brain noninvasively using two different 1H NMR spectroscopy methods: short-echo time STEAM and MEGA-PRESS homonuclear editing. Taking advantage of increased sensitivity and chemical shift dispersion at 7 T, Asc was quantified with increased reliability relative to our previous study accomplished at 4 T. Asc concentration quantified from short-echo time spectra measured from the occipital lobe of eight healthy subjects ([Asc] = 1.1 ± 0.3 µmol/g, mean ± SD) was in excellent agreement with Asc concentration quantified from the same volume of interest using homonuclear ...
Source: NMR in Biomedicine - August 4, 2009 Category: Radiology Authors: Melissa Terpstra, Kamil Ugurbil, Ivan Tkac Source Type: journals

Diffusion tensor imaging detects axonal injury and demyelination in the spinal cord and cranial nerves of a murine model of globoid cell leukodystrophyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Globoid cell leukodystrophy is an inherited neurodegenerative disorder caused by a deficiency of the lysosomal enzyme galactosylceramidase. In both human patients and the authentic murine Twitcher model, pathological findings include demyelination as well as axonal damage in both the central and peripheral nervous system. Diffusion tensor imaging (DTI) has emerged as a powerful noninvasive technique that is sensitive to these white matter disease processes. Increases in radial diffusivity ([lambda][perp]) and decreases in axial diffusivity ([lambda][par]) correlate with histopathological evidence of demyelination and axona...
Source: NMR in Biomedicine - July 31, 2009 Category: Radiology Authors: A. Alex Hofling, Joong Hee Kim, Corinne R. Fantz, Mark S. Sands, Sheng-Kwei Song Source Type: journals

Monitoring angiogenesis in soft-tissue engineered constructs for calvarium bone regeneration: an in vivo longitudinal DCE-MRI studyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tissue engineering is a promising technique for bone repair and can overcome the major drawbacks of conventional autogenous bone grafting. In this in vivo longitudinal study, we proposed a new tissue-engineering paradigm: inserting a biological soft-tissue construct within the bone defect to enhance angiogenesis for improved bone regeneration. The construct acts as a resorbable scaffold to support desired angiogenesis and cellular activity and as a vector of vascular endothelial growth factor, known to promote both vessel and bone growth. Dynamic contrast- enhanced magnetic resonance imaging was performed to investigate an...
Source: NMR in Biomedicine - July 30, 2009 Category: Radiology Authors: Marine Beaumont, Marc G. DuVal, Yasir Loai, Walid A. Farhat, George K. Sándor, Hai-Ling Margaret Cheng Source Type: journals

Assessment of early docetaxel response in an experimental model of human breast cancer using DCE-MRI, ex vivo HR MAS, and in vivo 1H MRSEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study DCE-MRI, in vivo MRS and ex vivo HR MAS MRS have been used to demonstrate that docetaxel treatment of a human breast cancer xenograft model results in changes in the vascular dynamics and metabolic profile of the tumors. This indicates that these MR methods could be used to monitor intra-tumoral treatment effects. Copyright © 2009 John Wiley & Sons, Ltd. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - July 30, 2009 Category: Radiology Authors: Line R. Jensen, Else M. Huuse, Tone F. Bathen, Pål E. Goa, Anna M. Bofin, Tina B. Pedersen, Steinar Lundgren, Ingrid S. Gribbestad Source Type: journals

A comparison of the ADC and T2 mapping in an assessment of blood-clot lysabilityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The structural characteristics of blood clots are associated with their susceptibility to thrombolysis. As their morphology can be characterized by MRI, several attempts have been made to link the lysability of blood clots with their MRI properties; however, so far no study has associated a clot's lysability with the diffusion properties of the water in the clot. The apparent diffusion coefficient (ADC) is highly sensitive to changes in serum mobility and may be used to distinguish between the non-retracted and the fully retracted regions of the blood clot. Therefore, the ADC may be a suitable, or even a better, marker for...
Source: NMR in Biomedicine - July 28, 2009 Category: Radiology Authors: Jernej Vidmar, Ale[scaron] Blinc, Igor Ser[scaron]a Source Type: journals

Understanding and manipulating the RF fields at high field MRIEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper presents a complete overview of the electromagnetics (radiofrequency aspect) of MRI at low and high fields. Using analytical formulations, numerical modeling (computational electromagnetics), and ultrahigh field imaging experiments, the physics that impacts the electromagnetic quantities associated with MRI, namely (1) the transmit field, (2) receive field, and (3) total electromagnetic power absorption, is analyzed. The physical interpretation of the above-mentioned quantities is investigated by electromagnetic theory, to understand 'What happens, in terms of electromagnetics, when operating at different static...
Source: NMR in Biomedicine - July 18, 2009 Category: Radiology Authors: Tamer S. Ibrahim, YiK-Kiong Hue, Lin Tang Source Type: journals

Diffusion tensor imaging of the human calf muscle: distinct changes in fractional anisotropy and mean diffusion due to passive muscle shortening and stretchingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The influence of passive shortening and stretching of the calf muscles on diffusion characteristics was investigated. The diffusion tensor was measured in transverse slices through the lower leg of eight healthy volunteers (29 ± 7 years) on a 3 T whole-body MR unit in three different positions of the foot (40° plantarflexion, neutral ankle position (0°), and -10° dorsiflexion in the ankle). Maps of the mean diffusivity, the three eigenvalues of the tensor and fractional anisotropy (FA) were calculated. Results revealed a distinct dependence of the mean diffusivity and FA on the foot position and the related shortening ...
Source: NMR in Biomedicine - July 16, 2009 Category: Radiology Authors: Nina F. Schwenzer, Günter Steidle, Petros Martirosian, Christina Schraml, Fabian Springer, Claus D. Claussen, Fritz Schick Source Type: journals

Cardiac phenotyping in ex vivo murine embryos using µMRIEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Microscopic MRI (µMRI) is an emerging technique for high-throughput phenotyping of transgenic mouse embryos, and is capable of visualising abnormalities in cardiac development. To identify cardiac defects in embryos, we have optimised embryo preparation and MR acquisition parameters to maximise image quality and assess the phenotypic changes in chromodomain helicase DNA-binding protein 7 (Chd7) transgenic mice. µMRI methods rely on tissue penetration with a gadolinium chelate contrast agent to reduce tissue T1, thus improving signal-to-noise ratio (SNR) in rapid gradient echo sequences. We investigated 15.5 days post coi...
Source: NMR in Biomedicine - July 13, 2009 Category: Radiology Authors: Jon O. Cleary, Anthony N. Price, David L. Thomas, Peter J. Scambler, Vanessa Kyriakopoulou, Karen McCue, Jürgen E. Schneider, Roger J. Ordidge, Mark F. Lythgoe Source Type: journals

BOLD-specific cerebral blood volume and blood flow changes during neuronal activation in humansEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
To understand and predict the blood-oxygenation level-dependent (BOLD) fMRI signal, an accurate knowledge of the relationship between cerebral blood flow ([Delta]CBF) and volume ([Delta]CBV) changes is critical. Currently, this relationship is widely assumed to be characterized by Grubb's power-law, derived from primate data, where the power coefficient ([alpha]) was found to be 0.38. The validity of this general formulation has been examined previously, and an [alpha] of 0.38 has been frequently cited when calculating the cerebral oxygen metabolism change ([Delta]CMRo2) using calibrated BOLD. However, the direct use of th...
Source: NMR in Biomedicine - July 12, 2009 Category: Radiology Authors: J. Jean Chen, G. Bruce Pike Source Type: journals

A multivariate hypothesis testing framework for tissue clustering and classification of DTI dataEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The primary aim of this work is to propose and investigate the effectiveness of a novel unsupervised tissue clustering and classification algorithm for diffusion tensor MRI (DTI) data. The proposed algorithm utilizes information about the degree of homogeneity of the distribution of diffusion tensors within voxels. We adapt frameworks proposed by Hext and Snedecor, where the null hypothesis of diffusion tensors belonging to the same distribution is assessed by an F-test. Tissue type is classified according to one of the four possible diffusion models, the assignment of which is determined by a parsimonious model selection ...
Source: NMR in Biomedicine - July 10, 2009 Category: Radiology Authors: Raisa Z. Freidlin, Evren Özarslan, Yaniv Assaf, Michal E. Komlosh, Peter J. Basser Source Type: journals

Profiling human gut bacterial metabolism and its kinetics using [U-13C]glucose and NMREmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study introduces a stable-isotope metabolic approach employing [U-13C]glucose that, as a novelty, allows selective profiling of the human intestinal microbial metabolic products of carbohydrate food components, as well as the measurement of the kinetics of their formation pathways, in a single experiment. A well-established, validated in vitro model of human intestinal fermentation was inoculated with standardized gastrointestinal microbiota from volunteers. After culture stabilization, [U-13C]glucose was added as an isotopically labeled metabolic precursor. System lumen and dialysate samples were taken at regular int...
Source: NMR in Biomedicine - July 9, 2009 Category: Radiology Authors: Albert A. de Graaf, Annet Maathuis, Pieter de Waard, Nicolaas E. P. Deutz, Cor Dijkema, Willem M. de Vos, Koen Venema Source Type: journals

N-acetyl resonances in in vivo and in vitro NMR spectroscopy of cystic ovarian tumorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An unassigned and prominent resonance in the region from [delta] 2.0-2.1 ppm has frequently been found in the in vivo MR spectra of cancer patients. We demonstrated the presence of this resonance with in vivo MRS in the cyst fluid of a patient with an ovarian tumor. 1H-NMRS on the aspirated cyst fluid of this patient confirmed the observation. A complex of resonances was observed between 2.0 and 2.1 ppm. It was also present in 11 additional ovarian cyst fluid samples randomly chosen from our biobank. The resonance complex was significantly more prominent in samples from mucinous tumors than in samples from other histologic...
Source: NMR in Biomedicine - July 9, 2009 Category: Radiology Authors: Eva Kolwijck, Udo F. Engelke, Marinette van der Graaf, Arend Heerschap, Henk J. Blom, M'Hamed Hadfoune, Wim A. Buurman, Leon F. Massuger, Ron A. Wevers Source Type: journals

Assessing manganese efflux using SEA0400 and cardiac T1-mapping manganese-enhanced MRI in a murine modelEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study used the MEMRI technique to examine the temporal features of cardiac Mn2+ efflux by implementing a T1-mapping method and inhibiting the NCX with SEA0400. The change in 1H2O longitudinal relaxation rate, [Delta]R1, in the left ventricular free wall, was calculated at different time points following infusion of 190 nmol/g manganese chloride (MnCl2) in healthy adult male mice. The results showed 50% MEMRI signal attenuation at 3.4 ± 0.6 h post-MnCl2 infusion without drug intervention. Furthermore, treatment with 50 ± 0.2 mg/kg of SEA0400 significantly reduced the rate of decrease in [Delta]R1. At 4.9-5.9 h post-M...
Source: NMR in Biomedicine - July 9, 2009 Category: Radiology Authors: Ben Waghorn, Yuhui Yang, Akemichi Baba, Toshio Matsuda, Autumn Schumacher, Nathan Yanasak, Tom C.-C. Hu Source Type: journals

Evaluation of the proximal tubular function in individuals with primary renal hypouricemia: an NMR-based metabonomic studyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Primary renal hypouricemia (PRH) refers to a rare condition of increased renal urate clearance, caused by an isolated inborn error of membrane transport of urate in the renal proximal tubule. Several cases of exercise-induced acute renal failure and urolithiasis have been reported. This is the first study that assessed tubular function in PRH using NMR-based metabonomic urine analysis. The study groups consisted of 36 unrelated asymptomatic subjects with PRH, defined as serum uric acid levels (sUA) 10%, after exclusion of diseases and drugs that may affect urate homeostasis, and 39 sex and age-matched healthy individuals w...
Source: NMR in Biomedicine - July 9, 2009 Category: Radiology Authors: Vasilios T. Tzovaras, Nikolaos G. Psychogios, Christina E. Kostara, Eleni T. Bairaktari, Moses S. Elisaf Source Type: journals

Measuring SPIO and Gd contrast agent magnetization using 3 T MRIEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Traditional methods of measuring magnetization in magnetic fluid samples, such as vibrating sample magnetometry (VSM), are typically limited to maximum field strengths of about 1 T. This work demonstrates the ability of MRI to measure the magnetization associated with two commercial MRI contrast agents at 3 T by comparing analytical solutions to experimental imaging results for the field pattern associated with agents in cylindrical vials. The results of the VSM and fitted MRI data match closely. The method represents an improvement over VSM measurements since results are attainable at imaging field strengths. The agents i...
Source: NMR in Biomedicine - July 7, 2009 Category: Radiology Authors: Pádraig Cantillon-Murphy, Lawrence L. Wald, Markus Zahn, Elfar Adalsteinsson Source Type: journals

Improving SNR of RF coils using composite coil elementsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A composite coil element consists of up to three independent orthogonal loops. It improves the flexibility in shaping the radio frequency (RF) field in its vicinity, compared with a single-loop coil element. Computer simulations were conducted to explore the potential advantages of this type of coil configuration for improving the signal-to- noise ratio (SNR), including the intrinsic SNR (ISNR) and the realistic SNR, when the effects of resistive loss of the coil were included. A 'half-space' model was considered, with a variable B0 direction relative to the surface of a large conductive medium. The SNR performance of a sq...
Source: NMR in Biomedicine - July 6, 2009 Category: Radiology Authors: Zhiyue J. Wang Source Type: journals

Comparison of oxidative capacity among leg muscles in humans using gated 31P 2-D chemical shift imagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In many small animals there are distinct differences in fiber-type composition among limb muscles, and these differences typically correspond to marked disparities in the oxidative capacities. However, whether there are similar differences in the oxidative capacity among leg muscles in humans is less clear. The purpose of this study was to compare the rate of phosphocreatine (PCr) recovery, a functional in vivo marker of oxidative capacity, in the lateral and medial gastrocnemius, soleus, and the anterior compartment of the leg (primarily the tibialis anterior) of humans. Subjects performed plantar flexion and dorsiflexion...
Source: NMR in Biomedicine - July 4, 2009 Category: Radiology Authors: Sean C. Forbes, Jill M. Slade, Ryan M. Francis, Ronald A. Meyer Source Type: journals

Classification of prostatic diseases by means of multivariate analysis on in vivo proton MRSI and DCE-MRI dataEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we show how this approach, applied to 1H-MRSI/DCE-MRI results, allows us to differentiate among the various prostatic diseases in a non-invasive way with a 100% accuracy. These findings suggest that multivariate analysis of 1H-MRSI/DCE-MRI can significantly improve the diagnostic accuracy for these pathological entities. From a more theoretical point of view, the complementation of a single biomarker approach with an integrated picture of the entire metabolic and dynamic profile allows for a more realistic appreciation of pathological entities. Copyright © 2009 John Wiley & Sons, Ltd. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - July 2, 2009 Category: Radiology Authors: Mariacristina Valerio, Valeria Panebianco, Alessandro Sciarra, Marcello Osimani, Stefano Salsiccia, Lorena Casciani, Alessandro Giuliani, Mariano Bizzarri, Franco Di Silverio, Roberto Passariello, Filippo Conti Source Type: journals

Evidence for in vivo macrophage mediated tumor uptake of paramagnetic/fluorescent liposomesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Dysprosium (Dy)-loaded liposomes act as excellent T2-susceptibility agents at high magnetic field strength. The R2-enhancement increases with the size of the liposomes and the concentration of entrapped paramagnetic metal complexes. Neuro-2a tumor cells are readily labeled when Dy-loaded liposomes, suitably functionalized with glutamine residues (Gln), are added to the culture medium as glutamine receptors are highly expressed in such proliferating tumor cells. By using fluorescent liposomes doped with fluorescent dyes (either incorporated in the membrane or included in the inner cavity), confocal microscopy experiments sh...
Source: NMR in Biomedicine - June 29, 2009 Category: Radiology Authors: Daniela Delli Castelli, Enzo Terreno, Claudia Cabella, Linda Chaabane, Stefania Lanzardo, Lorenzo Tei, Massimo Visigalli, Silvio Aime Source Type: journals

Non-invasive determination of tissue thermal parameters from high intensity focused ultrasound treatment monitored by volumetric MRI thermometryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A method is proposed for estimating the perfusion rate, thermal diffusivity, and the absorption coefficient that influence the local temperature during high intensity focused ultrasound (HIFU) thermotherapy procedures. For this purpose, HIFU heating experiments (N = 100) were performed ex vivo on perfused porcine kidney (N = 5) under different flow conditions. The resulting spatio-temporal temperature variations were measured non-invasively by rapid volumetric MR-temperature imaging. The bio-heat transfer (BHT) model was adapted to describe the spatio-temporal evolution of tissue temperature in the cortex. Absorption and p...
Source: NMR in Biomedicine - June 26, 2009 Category: Radiology Authors: Iulius Dragonu, Philippe Lourenço de Oliveira, Christophe Laurent, Charles Mougenot, Nicolas Grenier, Chrit T. W. Moonen, Bruno Quesson Source Type: journals

Micro MRI of the mouse brain using a novel 400 MHz cryogenic quadrature RF probeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, this low temperature detection device represents an attractive option to increase the performance of small animal MR systems operating at 9.4 Tesla. Copyright © 2009 John Wiley & Sons, Ltd. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - June 24, 2009 Category: Radiology Authors: Christof Baltes, Nicole Radzwill, Simone Bosshard, Daniel Marek, Markus Rudin Source Type: journals

Pitfalls and advantages of different strategies for the absolute quantification of N-acetyl aspartate, creatine and choline in white and grey matter by 1H-MRSEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study extensively investigates different strategies for the absolute quantitation of N-acetyl aspartate, creatine and choline in white and grey matter by 1H-MRS at 1.5 T. The main focus of this study was to reliably estimate metabolite concentrations while reducing the scan time, which remains as one of the main problems in clinical MRS. Absolute quantitation was based on the water-unsuppressed concentration as the internal standard. We compared strategies based on various experimental protocols and post-processing strategies. Data were obtained from 30 control subjects using a PRESS sequence at several TE to estimate...
Source: NMR in Biomedicine - June 8, 2009 Category: Radiology Authors: E. Malucelli, D. N. Manners, C. Testa, C. Tonon, R. Lodi, B. Barbiroli, S. Iotti Source Type: journals

Characterizing pulmonary blood flow distribution measured using arterial spin labelingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The arterial spin labeling (ASL) method provides images in which, ideally, the signal intensity of each image voxel is proportional to the local perfusion. For studies of pulmonary perfusion, the relative dispersion (RD, standard deviation/mean) of the ASL signal across a lung section is used as a reliable measure of flow heterogeneity. However, the RD of the ASL signals within the lung may systematically differ from the true RD of perfusion because the ASL image also includes signals from larger vessels, which can reflect the blood volume rather than blood flow if the vessels are filled with tagged blood during the imagin...
Source: NMR in Biomedicine - June 5, 2009 Category: Radiology Authors: A. Cortney Henderson, G. Kim Prisk, David L. Levin, Susan R. Hopkins, Richard B. Buxton Source Type: journals

Rapid 3D radiofrequency field mapping using catalyzed double-angle methodEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A new method is presented for rapid and accurate large volumetric radiofrequency (RF) field (B1+) mapping. This method is a modification of the double-angle method (DAM), which accelerates imaging speed and applies 3D acquisition to improve B1+ measurement accuracy. It reduces repetition time and scan time by introducing a catalyzation RF pulse chain at the end of each DAM repetition cycle. The catalyzation pulse chain ensures that, after each TR period, the longitudinal magnetizations reach the same state for both measurements at two flip angles for the DAM so that the long TR requirement (TR [ge] 5 T1) for complete relax...
Source: NMR in Biomedicine - June 2, 2009 Category: Radiology Authors: Dingxin Wang, Sven Zuehlsdorff, Andrew C. Larson Source Type: journals

Accelerated spectroscopic imaging of hyperpolarized C-13 pyruvate using SENSE parallel imagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The ability to accelerate the spatial encoding process during a chemical shift imaging (CSI) scan of hyperpolarized compounds is demonstrated through parallel imaging. A hardware setup designed to simultaneously acquire 13C data from multiple receivers is presented here. A system consisting of four preamplifiers, four gain stages, a transmit coil, and a four receive channel rat coil was built for single channel excitation and simultaneous multi-channel detection of 13C signals. The hardware setup was integrated with commercial scanner electronics, allowing the system to function similar to a conventional proton multi-chann...
Source: NMR in Biomedicine - June 1, 2009 Category: Radiology Authors: Arjun Arunachalam, David Whitt, Kenneth Fish, Randy Giaquinto, Joseph Piel, Ronald Watkins, Ileana Hancu Source Type: journals

Comparison of MRI signatures in pattern I and II multiple sclerosis modelsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The majority of individuals with multiple sclerosis (MS) exhibit T-cell- and macrophage-dominated lesions (patterns I and II; as opposed to III and IV). These lesions, in turn, may be distinguished on the basis of whether or not there are immunoglobulin and complement depositions at the sites of active myelin destruction; such depositions are found exclusively in pattern II lesions. The main aim of this study was to determine whether pattern I and pattern II MS lesions exhibit distinct MRI signatures. We have used a recently described focal MOG-induced EAE model of the rat brain, which recapitulates many of the hallmarks o...
Source: NMR in Biomedicine - June 1, 2009 Category: Radiology Authors: Sébastien Serres, Daniel C. Anthony, Yanyan Jiang, Sandra J. Campbell, Kerry A. Broom, Alexandre Khrapitchev, Nicola R. Sibson Source Type: journals

Magnetic resonance imaging and biological properties of pancreatic islets labeled with iron oxide nanoparticlesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study was undertaken to investigate the in vitro effect of islet labeling with iron oxide nanoparticles for MRI on islet viability, insulin secretion, and gene expression. Isolated rat islets were labeled with Resovist (25-200 µg Fe/mL, a clinically approved MRI contrast agent) in the presence or absence of poly-l-Lysine (PLL, 1.5 µg/mL) for 48 h. The iron content of labeled islets was found to increase in a dose-dependent manner. More than 90% of the islets were labeled with 100 µg Fe/mL. We confirmed the localizations of iron oxide nanoparticles within islet [beta]-cells by insulin immunostaining. As the concentr...
Source: NMR in Biomedicine - June 1, 2009 Category: Radiology Authors: Hoe Suk Kim, YoonSeok Choi, In Chan Song, Woo Kyung Moon Source Type: journals