Lawrence Dougherty

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Magnetic resonance tissue tagging allows noninvasive in vivo measurement of soft tissue deformation. Planes of magnetic saturation are created, orthogonal to the imaging plane, which form dark lines (stripes) in the image. The authors describe a method for tracking stripe motion in the image plane, and show how this information can be incorporated into a(More)
A previously reported method of using magnetic resonance (MR) imaging to study heart wall motion involves a pair of nonselective radio-frequency (RF) pulses, separated by a magnetic field gradient pulse, prior to imaging; this produces images with a regular pattern of stripes that move with the heart wall and that have a sinusoidal intensity profile. It is(More)
OBJECTIVE The objective of our study was to predict response to chemoradiation therapy in patients with head and neck squamous cell carcinoma (HNSCC) by combined use of diffusion-weighted imaging (DWI) and high-spatial-resolution, high-temporal-resolution dynamic contrast-enhanced MRI (DCE-MRI) parameters from primary tumors and metastatic nodes. SUBJECTS(More)
The paramagnetic magnetic resonance (MR) imaging contrast agent gadolinium diethylenetriaminepentaacetic acid (DTPA) is freely filtered at the glomerulus and is neither secreted nor reabsorbed by the renal tubules. Fast MR imaging techniques, either gradient-echo or spin-echo, can be used to document the passage of Gd-DTPA through the renal tubules, as(More)
Myocardial tagging with magnetic resonance imaging is useful for non-invasive estimation of in vivo heart wall deformation. To validate the method of strain estimation and quantify the error of deformation estimates, a deformable silicone gel phantom in the shape of a cylindrical anulus was built and imaged. Four observers digitized the displacement of(More)
OBJECTIVES The objectives of this study were to develop and show the efficacy of a breath-hold ultrafast three-dimensional (3D) spoiled gradient-echo (SPGR) gadolinium-enhanced MR angiographic technique for imaging the aorta and the renal and other visceral arteries of the abdomen; and to compare breath-hold ultrafast 3D SPGR with two-dimensional (2D)(More)
RATIONALE AND OBJECTIVES This study was performed to evaluate an optical flow method for registering serial computed tomographic (CT) images of lung volumes to assist physicians in visualizing and assessing changes between CT scans. MATERIALS AND METHODS The optical flow method is a coarse-to-fine model-based motion estimation technique for estimating(More)
A method for dynamic imaging in MRI is presented that enables the acquisition of a series of images with both high temporal and high spatial resolution. The technique, which is based on the projection reconstruction (PR) imaging scheme, utilizes distinct data acquisition and reconstruction strategies to achieve this simultaneous capability. First, during(More)
A novel technique for manipulating contrast in projection reconstruction MRI is described. The method takes advantage of the fact that the central region of k-space is oversampled, allowing one to choose different filters to enhance or reduce the amount that each view contributes to the central region, which dominates image contrast. The technique is(More)