Search Results
You are looking at 1 - 4 of 4 items for
- Author or Editor: Carol Muehleman x
- Refine by access: All Content x
Refraction Effects of Diffraction-Enhanced Radiographic Imaging
A New Look at Bone
The objective of this study was to demonstrate the ability of a novel radiographic technology—diffraction-enhanced imaging—to detect contrast in bone tissue through absorption, refraction, and scatter rejection. Diffraction-enhanced imaging uses a synchrotron x-ray beam to produce images of high contrast by measuring the object’s refraction and ultra-small angle scattering of x-rays in addition to the attenuation measured by conventional radiography. We present evidence that diffraction-enhanced imaging provides contrast enhancement at the edges of cortical and cancellous bone and a three-dimensional appearance of trabeculae. (J Am Podiatr Med Assoc 94(5): 453–455, 2004)
Background: We sought to determine whether symptomatic medial knee osteoarthritis is associated with aberrant loading across the foot during gait.
Methods: Twenty-five individuals with medial knee osteoarthritis were compared with 25 controls. Knee radiographs and Western Ontario and McMaster Universities Arthritis Index questionnaires were obtained. Participants walked barefoot over pressure sensors, and the center-of-pressure trace was plotted against the axis of the foot, and a center-of-pressure index was calculated.
Results: The center-of-pressure indices in the medial knee osteoarthritis group demonstrated high lateral loading compared with the central center-of-pressure pattern in controls (P < .001). There was a correlation between the severity of pain and the center-of-pressure index in patients with medial knee osteoarthritis but no correlation between center of pressure and radiographic severity.
Conclusions: The plantar pressure patterns of patients with medial knee osteoarthritis demonstrated greater loading of the lateral aspect of the foot during the contact and midstance phases of gait but not during propulsion compared with those of controls, suggesting that loading patterns in the feet are related to osteoarthritis in the knee. (J Am Podiatr Med Assoc 100(3): 178–184, 2010)
Osteoarthritis is a disease of synovial joints that involves articular cartilage breakdown with accompanying bone changes, including subchondral sclerosis and osteophytosis. However, conflicting data have been reported concerning the cause-and-effect relationship, if any, between these changes. The authors studied the subchondral plate (subchondral bone plus calcified cartilage) in relation to the degree of articular cartilage degeneration on the distal articular surface of the first metatarsal, a region prone to osteoarthritis. No correlation was found between subchondral plate thickness or porosity and the degree of cartilage degeneration in the study sample of 96 metatarsals. Owing to the suggestion that initiation of cartilage fibrillation may be a result of steep stiffness gradients in the subchondral bone, the ratios of subchondral plate thickness in adjacent regions of the metatarsal head were examined in detail, but no correlation was found with subchondral degeneration. Thus increases in subchondral bone thickness are not associated with increases in cartilage degeneration on the first metatarsal, which may imply that subchondral bone changes do not cause osteoarthritis in this joint. (J Am Podiatr Med Assoc 93(2): 104-110, 2003)
Non-calcified tissues, including tendons, ligaments, adipose tissue and cartilage, are not visible, for any practical purposes, with conventional X-ray imaging. Therefore, any pathological changes in these tissues generally necessitate detection through magnetic resonance imaging or ultrasound technology. Until recently the development of an X-ray imaging technique that could detect both bone and soft tissues seemed unrealistic. However, the introduction of diffraction enhanced X-ray imaging (DEI) which is capable of rendering images with absorption, refraction and scatter rejection qualities has allowed detection of specific soft tissues based on small differences in tissue densities. Here we show for the first time that DEI allows high contrast imaging of soft tissues, including ligaments, tendons and adipose tissue, of the human foot and ankle. (J Am Podiatr Med Assoc 94(3): 315–322, 2004)
