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BACKGROUND AND PURPOSE Although research with functional MR imaging of the brain has proliferated over the past 5 years, technical limitations, such as motion, chemical shift, and susceptibility artifacts, have impeded such research in the human spinal cord. The purpose of this investigation was to determine whether a reliable functional MR imaging signal(More)
The purpose of this work was to optimize and increase the accuracy of tissue segmentation of the brain magnetic resonance (MR) images based on multispectral 3D feature maps. We used three sets of MR images as input to the in-house developed semi-automated 3D tissue segmentation algorithm: proton density (PD) and T2-weighted fast spin echo and, T1-weighted(More)
The aim of this work was to develop a fast and accurate method for tissue segmentation in magnetic resonance imaging (MRI) based on a four-dimensional (4D) feature map and compare it with that derived from a 3D feature map. High-resolution MRI was performed in 5 normal individuals, in 12 patients with brain multiple sclerosis (MS), and 9 patients with(More)
Our aim was to develop an accurate multispectral tissue segmentation method based on 3D feature maps. We utilized proton density (PD), T2-weighted fast spin-echo (FSE), and T1-weighted spin-echo images as inputs for segmentation. Phantom constructs, cadaver brains, an animal brain tumor model and both normal human brains and those from patients with either(More)
MRI is a very sensitive imaging modality, however with relatively low specificity. The aim of this work was to determine the potential of image post-processing using 3D-tissue segmentation technique for identification and quantitative characterization of intracranial lesions primarily in the white matter. Forty subjects participated in this study: 28(More)
We investigated in vitro NMR properties of bleomycin-induced alveolitis and pulmonary fibrosis in 18 Lewis rats (6 controls). When alveolitis or fibrosis had developed, animal lungs were excised and examined histologically and gravimetrically and their T1 and T2 were determined by a NMR spectrometer at 10.7 MHz and 37 degrees C. Clinical diagnosis was(More)
Three patients with focal brain-stem oculomotor disturbances (nuclear sixth nerve syndrome, sixth nerve palsy, bilateral internuclear ophthalmoplegia) as a consequence of multiple sclerosis have been studied with high-volume delayed computed tomography and high-field magnetic resonance imaging. In all of them, high-volume delayed computed tomography was(More)
Effects of the sampling rate on spatial resolution and the signal-to-noise ratio in spin-echo MR imaging were calculated. The theoretical results suggest that as T2* decreases, due to either static magnetic field inhomogeneities or shortened T2 relaxation times, the calculated optimum sampling rate increases accordingly. Since biological tissues exhibit(More)
Magnetic resonance angiography (MRA) hs inherent artifacts due to variation in velocity and direction of flowing blood in the carotid bulb and regions of stenosis. We examined the efficiency of dual 3-inch surface coils to delineate carotid artery flow better. Carotid MRA was performed on ten healthy volunteers and six patients, on a 1.5 T system. A special(More)