Medical and Biomedical Researches

Assessing transneuronal dysfunction utilizing manganese-enhanced MRI (MEMRI).

June 28th, 2008
Assessing transneuronal dysfunction utilizing manganese-enhanced MRI (MEMRI). In this study we utilized manganese-enhanced MRI (MEMRI) to evaluate the in vivo transneuronal efficiency of manganese ion (Mn(2+)) movement as a means to assess overall changes in neuronal function. We designated this extension the manganese transfer index (MTI) ...

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Impact of heart rate variability in patients with normal sinus rhythm on image quality in coronary m

June 28th, 2008
Impact of heart rate variability in patients with normal sinus rhythm on image quality in coronary magnetic angiography. PURPOSE: To evaluate the influence of heart rate variability on image quality in patients with suspected coronary artery disease during magnetic resonance coronary angiography (MRCA). MATERIALS AND METHODS: ...

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Principles of whole-body continuously-moving-table MRI.

June 28th, 2008
Principles of whole-body continuously-moving-table MRI. Continuously-moving-table (CMT) imaging is a new and promising approach to virtually extend the field-of-view (FOV) in currently available MRI systems. It shows high potential to improve a number of applications that require a large FOV, such as whole-body contrast-enhanced angiography and ...

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Reproducibility of MRI measurements of right ventricular size and function in patients with normal a

June 28th, 2008
Reproducibility of MRI measurements of right ventricular size and function in patients with normal and dilated ventricles. PURPOSE: To determine the inter- and intraobserver reproducibility of cardiac magnetic resonance (CMR)-derived measurements of right ventricular (RV) mass, volume, and function in patients with normal and dilated ventricles. ...

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Cardiac cine MRI: Quantification of the relationship between fast gradient echo and steady-state fre

June 28th, 2008
Cardiac cine MRI: Quantification of the relationship between fast gradient echo and steady-state free precession for determination of myocardial mass and volumes. PURPOSE: To determine the correlation function between the steady-state free precession (SSFP) and fast gradient echo (FGRE) cine MRI pulse sequences for measuring the ...

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Generalized Reconstruction by Inversion of Coupled Systems (GRICS) applied to free-breathing MRI.

June 28th, 2008
Generalized Reconstruction by Inversion of Coupled Systems (GRICS) applied to free-breathing MRI. A reconstruction strategy is proposed for physiological motion correction, which overcomes many limitations of existing techniques. The method is based on a general framework allowing correction for arbitrary motion-nonrigid or affine, making it suitable ...

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Kalman filtering for real-time navigator processing.

June 28th, 2008
Kalman filtering for real-time navigator processing. Navigator echoes are used in high-resolution cardiac MRI for tracking physiological motion to suppress motion artifacts. Alternatives to the conventional diaphragm navigator such as the cardiac fat navigator and the k-space center signal (self-navigator) were developed to monitor heart motion ...

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Concomitant field terms for asymmetric gradient coils: Consequences for diffusion, flow, and echo-pl

June 28th, 2008
Concomitant field terms for asymmetric gradient coils: Consequences for diffusion, flow, and echo-planar imaging. As a consequence of the Maxwell equations, linear field gradients are accompanied by additional spatially dependent field components. A description of the Maxwell field terms is presented which explicitly takes into account ...

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Quantitative myocardial perfusion imaging using different autocalibrated parallel acquisition techni

June 28th, 2008
Quantitative myocardial perfusion imaging using different autocalibrated parallel acquisition techniques. PURPOSE: To compare three different autocalibrated parallel acquisition techniques (PAT) for quantitative and semiquantitative myocardial perfusion imaging. MATERIALS AND METHODS: Seven healthy volunteers underwent myocardial first-pass perfusion imaging at rest using an SR-TrueFISP pulse sequence without ...

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Automatic computation of left ventricular ejection fraction from spatiotemporal information in cine-

June 28th, 2008
Automatic computation of left ventricular ejection fraction from spatiotemporal information in cine-SSFP cardiac MR images. PURPOSE: To clinically validate an algorithm that automatically computes left ventricular (LV) ejection fraction (LVEF) using a priori geometric and intrinsic spatiotemporal information from cine steady-state free precession (SSFP) MR images. ...

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Quantitative brain proton MR spectroscopy based on measurement of the relaxation time T(1) of water.

June 28th, 2008
Quantitative brain proton MR spectroscopy based on measurement of the relaxation time T(1) of water. PURPOSE: To provide a straightforward method for metabolite quantitation in the brain. Tissue water concentration can be determined in a voxel by measuring T(1) and it may provide an internal reference ...

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One-stop measurement of iron deposition in the anterior pituitary, liver, and heart in thalassemia p

June 28th, 2008
One-stop measurement of iron deposition in the anterior pituitary, liver, and heart in thalassemia patients. PURPOSE: To assess the feasibility of one-stop evaluation of iron load of myocardium, liver, and anterior pituitary gland in thalassemia patients. MATERIALS AND METHODS: Fifty thalassemia major patients underwent a breath-hold ...

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Abnormalities in T2-weighted cardiovascular magnetic resonance images of hypertrophic cardiomyopathy

June 28th, 2008
Abnormalities in T2-weighted cardiovascular magnetic resonance images of hypertrophic cardiomyopathy: Regional distribution and relation to late gadolinium enhancement and severity of hypertrophy. PURPOSE: To explore if focal T2 abnormalities accompany late gadolinium enhancement (LGE) lesions in hypertrophic cardiomyopathy (HCM). MATERIALS AND METHODS: All studies were performed ...

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3T MR with diffusion tensor imaging and single-voxel spectroscopy in giant axonal neuropathy.

June 28th, 2008
3T MR with diffusion tensor imaging and single-voxel spectroscopy in giant axonal neuropathy. Magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and MR spectroscopy (MRS) data were obtained in a patient with giant axonal neuropathy (GAN) and compared to a control group. Fractional anisotropy (FA) and ...

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Feasibility and reproducibility of relaxometry, morphometric, and geometrical measurements of the hi

June 28th, 2008
Feasibility and reproducibility of relaxometry, morphometric, and geometrical measurements of the hip joint with magnetic resonance imaging at 3T. PURPOSE: To test the feasibility of in vivo magnetic resonance T(1rho) relaxation time measurements of hip cartilage, and quantify the reproducibility of hip cartilage thickness, volume, T(2), ...

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Vascular space occupancy-dependent functional MRI by tissue suppression.

June 28th, 2008
Vascular space occupancy-dependent functional MRI by tissue suppression. PURPOSE: To measure the cerebral blood volume (CBV) dynamics during neural activation, a novel technique named vascular space occupancy (VASO)-based functional MRI (fMRI) was recently introduced for noninvasive CBV detection. However, its application is limited because of its ...

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MRI phase contrast velocity and flow errors in turbulent stenotic jets.

June 28th, 2008
MRI phase contrast velocity and flow errors in turbulent stenotic jets. PURPOSE: To clarify the use of MRI phase contrast (PC), as an alternative to Doppler echocardiography, when measuring high-velocity turbulent jets associated with stenotic valvular disease. MATERIALS AND METHODS: In vivo PC aortic stroke volume ...

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A regularized two-tensor model fit to low angular resolution diffusion images using basis directions

June 28th, 2008
A regularized two-tensor model fit to low angular resolution diffusion images using basis directions. PURPOSE: To resolve and regularize orientation estimates for two crossing fibers from images acquired with conventional diffusion tensor imaging (DTI) sampling schemes. MATERIALS AND METHODS: Partial volume causes artifacts in DTI. Given ...

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Investigation and validation of intersite fMRI studies using the same imaging hardware.

June 28th, 2008
Investigation and validation of intersite fMRI studies using the same imaging hardware. PURPOSE: To provide a between-site comparison of functional MRI (fMRI) signal reproducibility in two laboratories equipped with identical imaging hardware and software. Many studies have looked at within-subject reliability and more recent efforts have ...

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MRA of intracranial aneurysms embolized with platinum coils: A vascular phantom study at 1.5T and 3T

June 28th, 2008
MRA of intracranial aneurysms embolized with platinum coils: A vascular phantom study at 1.5T and 3T. PURPOSE: To analyze the influence of matrix and echo time (TE) of three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) on the depiction of residual flow in aneurysms embolized with ...

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Improved slice selection for R2* mapping during cryoablation with eddy current compensation.

June 28th, 2008
Improved slice selection for R2* mapping during cryoablation with eddy current compensation. PURPOSE: To improve the slice profile and image quality of R2* mapping in the iceball during cryoablation with ultrashort echo time (UTE) imaging by compensating for eddy currents induced by the selective gradient when ...

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3D nongadolinium-enhanced ECG-gated MRA of the distal lower extremities: Preliminary clinical experi

June 28th, 2008
3D nongadolinium-enhanced ECG-gated MRA of the distal lower extremities: Preliminary clinical experience. PURPOSE: To report our initial experience implementing a noncontrast-enhanced electrocardiograph (ECG) gated fast spin echo magnetic resonance angiography (MRA) technique for assessment of the calf arteries. MATERIALS AND METHODS: Noncontrast MRA images of 36 ...

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Change in knee cartilage T2 in response to mechanical loading.

June 28th, 2008
Change in knee cartilage T2 in response to mechanical loading. PURPOSE: To assess the clinical feasibility of magnetic resonance (MR) imaging with a mechanical loading system for evaluation of load-bearing function in knee joints using cartilage T2 as a surrogate of cartilage matrix changes. MATERIALS AND ...

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Cartilage imaging at 3.0T with gradient refocused acquisition in the steady-state (GRASS) and IDEAL

June 28th, 2008
Cartilage imaging at 3.0T with gradient refocused acquisition in the steady-state (GRASS) and IDEAL fat-water separation. PURPOSE: To demonstrate the feasibility of evaluating the articular cartilage of the knee joint at 3.0T using gradient refocused acquisition in the steady-state (GRASS) and iterative decomposition of water and ...

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Molecular mimicry in innate immunity? The viral RNA recognition receptor TLR7 accelerates murine lup

June 28th, 2008
Molecular mimicry in innate immunity? The viral RNA recognition receptor TLR7 accelerates murine lupus. Toll-like receptors (TLR), such as TLR7, were first described as innate pathogen recognition receptors that trigger appropriate antimircrobial immune responses upon exposure to pathogen-associated molecules, e.g. viral ssRNA. In parallel to ongoing ...

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