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A method is proposed to estimate signal-to-noise ratio (SNR) values in phased array magnitude images, based on a region-of-interest (ROI) analysis. It is shown that the SNR can be found by correcting the measured signal intensity for the noise bias effects and by evaluating the noise variance as the mean square value of all the pixel intensities in a chosen(More)
OBJECTIVES We sought to determine the feasibility and potential of transesophageal magnetic resonance imaging (TEMRI) for quantifying atherosclerotic plaque burden in the aortic arch and descending thoracic aorta in comparison with transesophageal echocardiography (TEE). BACKGROUND Improved morphologic assessment of atherosclerotic plaque features in vivo(More)
Introduction: MRI provides excellent soft-tissue contrast and promises to improve image-guided prostate interventions, presently performed with ultrasound [1,2]. MRI-guided transperineal prostate biopsy has been demonstrated inside an open MRI scanner [3]. Transrectal prostate biopsy has been demonstrated inside a high-field MR scanner utilizing passive(More)
A method to calculate the ultimate intrinsic signal-to-noise ratio (SNR) in a magnetic resonance experiment for a point inside an arbitrarily shaped object is presented. The ultimate intrinsic SNR is determined by body noise. A solution is obtained by optimizing the electromagnetic field to minimize total power deposition while maintaining a constant(More)
A technique for transperineal high-dose-rate (HDR) prostate brachytherapy and needle biopsy in a standard 1.5 T MRI scanner is demonstrated. In each of eight procedures (in four patients with intermediate to high risk localized prostate cancer), four MRI-guided transperineal prostate biopsies were obtained followed by placement of 14-15 hollow transperineal(More)
This article presents a new method for measuring longitudinal strain in a short-axis section of the heart using harmonic phase magnetic resonance imaging (HARP-MRI). The heart is tagged using 1-1 SPAMM at end-diastole with tag surfaces parallel to a short-axis imaging plane. Two or more images are acquired such that the images have different phase encodings(More)
The purpose of this study was to develop a non-invasive method of imaging the thoracic aorta that would provide both morphological detail within the aortic wall and information about regional aortic wall motion. An esophageal probe is described that allows transesophageal MR imaging (TEMRI) of the thoracic aorta and has several potential advantages over the(More)
We have developed a method that can measure high-energy phosphate metabolite concentrations in humans with 1D resolved surface-coil NMR spectroscopy. The metabolites are measured by phosphorus (31P) NMR spectroscopy, and the tissue water proton (1H) resonance from the same volume serves as an internal concentration reference. The method requires only the(More)
This work reports a novel remotely actuated manipulator for transrectal prostate imaging and intervention, designed for use in a standard cylindrical, high-field magnetic resonance imaging (MRI) scanner. The device provides three-dimensional MRI guided needle placement with millimeter accuracy under physician control. Candidate procedures enabled by this(More)