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An enhancement to Dixon's technique is described which can provide error-free decomposition of water and fat proton images even in the presence of off-resonance conditions which result from susceptibility differences, demagnetization, or shim errors. The method uses three measurements with phase shifts of 0, pi, and -pi between the fat and water resonances.(More)
We discuss recent measurements of the wavelength-dependent absorption coefficients in deep South Pole ice. The method uses transit-time distributions of pulses from a variable-frequency laser sent between emitters and receivers embedded in the ice. At depths of 800-1000 m scattering is dominated by residual air bubbles, whereas absorption occurs both in ice(More)
This paper presents a fully automated method for segmenting articular knee cartilage and bone from in vivo 3-D dual echo steady state images. The magnetic resonance imaging (MRI) datasets were obtained from the Osteoarthritis Initiative (OAI) pilot study and include longitudinal images from controls and subjects with knee osteoarthritis (OA) scanned twice(More)
In the treatment of spine fractures and fracture-dislocations, stability of the spine is one of the major objectives. In the craniocervical joint, the alar and transverse ligaments provide much of the stability of the healthy spine. Because the anatomy appears well described, the contribution of each of these structures so far has received little attention.(More)
Eleven affected members of a large German-American family segregating recessively inherited, congenital, non-syndromic sensorineural hearing loss (SNHL) were found to be homozygous for the common 35delG mutation of GJB2, the gene encoding the gap junction protein Connexin 26. Surprisingly, four additional family members with bilateral profound SNHL carried(More)
PURPOSE Software-based image analysis is important for studies of cartilage changes in knee osteoarthritis (OA). This study describes an evaluation of a semi-automated cartilage segmentation software tool capable of quantifying paired images for potential use in longitudinal studies of knee OA. We describe the methodology behind the analysis and demonstrate(More)
Phased-array (PA) coils generally provide higher signal-to-noise ratios (SNRs) than quadrature knee coils. In this pilot study for the Osteoarthritis Initiative (OAI) we compared these two types of coils in terms of contrast-to-noise ratio (CNR), precision, and consistency of quantitative femorotibial cartilage measurements. Test-retest measurements were(More)
OBJECTIVE Fast low angle shot (FLASH) and double echo steady state (DESS) magnetic resonance imaging (MRI) acquisitions were recently cross-calibrated for quantification of cartilage morphology at 3T. In this pilot study for the osteoarthritis (OA) initiative we compare their test-retest-precision and sensitivity to longitudinal change. METHOD Nine(More)
In the process of prosthetic loosening, the initial motion of the implant relative to the bone is a key element. In order to provide quantitative information, three straight and one curved cementless hip stems were submitted to in vitro tests in autopsy specimens of the femur under dynamic axial and torsional loads with the displacements measured in several(More)