Journal of magnetic resonance imaging : JMRI
-
J Magn Reson Imaging · Mar 2007
Randomized Controlled Trial Comparative StudyDose comparison of single- vs. double-dose in contrast-enhanced magnetic resonance angiography of the carotid arteries: Intraindividual cross-over blinded trial using Gd-DTPA.
To compare the intraindividual differences of single-dose (D(S)) and double-dose (D(D)) gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced magnetic resonance angiography (MRA) in the carotid arterial territory, an open-label single-center trial with blinded evaluations by two independent radiologists was undertaken. ⋯ Our results demonstrate that while a double dosing of contrast agent does increase SNR, it does not lead to further improvement in visual and perceptual image quality. A single dosage of approximately 0.1 mmol/kg body weight (bw) Gd-DTPA may be the preferable dosage in the carotid arteries.
-
To combine gradient-echo (GRE) imaging with a multipoint water-fat separation method known as "iterative decomposition of water and fat with echo asymmetry and least squares estimation" (IDEAL) for uniform water-fat separation. Robust fat suppression is necessary for many GRE imaging applications; unfortunately, uniform fat suppression is challenging in the presence of B(0) inhomogeneities. These challenges are addressed with the IDEAL technique. ⋯ IDEAL-SPGR provides robust water-fat separation with optimized SNR performance at both 1.5T and 3.0T with multicoil acquisitions and parallel imaging in multiple regions of the body.
-
J Magn Reson Imaging · Mar 2007
Malignant-lesion segmentation using 4D co-occurrence texture analysis applied to dynamic contrast-enhanced magnetic resonance breast image data.
To investigate the use of four-dimensional (4D) co-occurrence-based texture analysis to distinguish between nonmalignant and malignant tissues in dynamic contrast-enhanced (DCE) MR images. ⋯ This study shows that a neural network classifier based on 4D texture analysis inputs can achieve a performance comparable to that achieved by human observers, and that further research in this area is warranted.
-
J Magn Reson Imaging · Mar 2007
Precision, signal-to-noise ratio, and dose optimization of magnitude and phase arterial input functions in dynamic susceptibility contrast MRI.
To determine optimal conditions for precise measurement of arterial input function (AIFs) in dynamic susceptibility contrast (DSC) perfusion MRI. ⋯ AIF SNR is affected most by signal type, then dosing, and lastly, SNR(I(0)).
-
J Magn Reson Imaging · Mar 2007
Projection-based estimation and nonuniformity correction of sensitivity profiles in phased-array surface coils.
To develop a novel approach for calculating the accurate sensitivity profiles of phased-array coils, resulting in correction of nonuniform intensity in parallel MRI. ⋯ The proposed method is more effective at correcting the intensity nonuniformity of phased-array surface-coil images than the conventional SOS method. In addition, the method was shown to be resilient to noise and was successfully applied for image reconstruction in parallel imaging.