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Biomedical subjects

M S Nixon

Publications and source records attributed to M S Nixon.

6 recordsLinked to original sources
PubMed2003

Lumbar spine visualisation based on kinematic analysis from videofluoroscopic imaging.

Low back pain is a significant problem and its cost is enormous to society. However, diagnosis of the underlying causes remains problematic despite extensive study. Reasons for this arise from the deep-rooted situation of the spine and also from its structural complexity. Clinicians have to mentally convert 2-D image information into a 3-D form to gain a better understanding of structural integrity. Therefore, visualisation and animation may be helpful for understanding, diagnosis and for guiding therapy. Some low back pain originates from mechanical disorders, and study of the spine kinematics may provide an insight into the source of the problem. Digital videofluoroscopy was used in this study to provide 2-D image sequences of the spine in motion, but the images often suffer due to noise, exacerbated by the very low radiation dosage. Thus determining vertebrae position within the image sequence presents a considerable challenge. This paper describes a combination of spine kinematic measurements with a solid model of the human lumbar spine for visualisation of spine motion. Since determination of the spine kinematics provides the foundation and vertebral extraction is at the core, this is discussed in detail. Edge detection is a key feature of segmentation and it is shown that phase congruency performs better than most established methods with the rather low-grade image sequences from fluoroscopy. The Hough transform is then applied to determine the positions of vertebrae in each frame of a motion sequence. In the Hough transform, Fourier descriptors are used to represent the vertebral shapes. The results show that the Hough transform is a very promising technique for vertebral extraction from videofluoroscopic images. A dynamic visualisation package has been developed in order to view the moving lumbar spine from any angle and viewpoint. Wire frame models of the vertebrae were built by using CT images from the Visible Human Project and these models are scaled to match the fluoroscopic image data. For animation, the spinal kinematic data from the motion study is incorporated.

Algorithms↗
PubMed1993

Development of a computer-assisted instructional tool for evaluation and treatment of renal masses. An experiment in hypermedia.

RATIONALE AND OBJECTIVES: Using a personal computer and a commercially available "authoring" application, the authors constructed an interactive hypermedia teaching tool for the evaluation and management of renal masses. METHODS AND RESULTS: Through a series of questions, images, illustrations, hypertext, and graphical flow charts, the user reviews the spectrum of renal masses, including neoplasms, inflammatory disease, cysts, and "pseudomasses." The various imaging modalities (computed tomography [CT], ultrasound [US], magnetic resonance imaging [MRI], and angiography) are illustrated, with selective advantages and disadvantages to each technique highlighted. Selected algorithms for evaluation and treatment of masses are provided. Text, questions, a teaching file, and algorithms form the major sections of the program. Numerous links within and between the major sections of the program, a capacity unique to hypermedia, allow for nonlinear entry into the program, tailored to the individual user. CONCLUSIONS: Preliminarily, medical students and residents have responded positively to this hypermedia project. Furthermore, their comments and criticism have provided important feedback for future updates and enhancements.

Computer-Assisted Instruction↗
PubMed1992

Computer-based radiological teaching programs: the challenge and trauma of development and implementation.

Computers are becoming an invaluable part of the radiologist's environment whether they are used as a source of the patient's clinical or laboratory information, to store x-ray or pathologic reports or as a viewing station for films. The use of computers in the educational environment is but a natural extension of the increased computerization of the radiologic department. This article reviews the use of personal computers in a teaching environment via the construction of the computed tomography teaching program entitled "CT: The Game." The decisions that must be made in terms of hardware and software prior to program development as well as the actual development are discussed. The potential of computers in terms of continuing education as well as in residency training programs is discussed with the potential for the future addressed.

Computer Systems↗
PubMed1991

The use of graphic design in an interactive computer teaching program.

The widespread diffusion of affordable computers into the scientific and educational community has provided the opportunity to design medical and scientific teaching programs illustrated either by hand or by utilizing commercially available software and manipulating existing computer generated images. The medical illustrator can provide the ideal aesthetic link between text format information and the visual representation of such knowledge in a concise presentation format. The availability of interactive multimedia programs has given the medical illustrator an environment to create and enhance Hypermedia designed specifically for the purpose of medical education. This paper will focus on the incorporation of illustration and screen design into "CT The Game," an experimental medical teaching program currently being developed in the Johns Hopkins Body CT Imaging Laboratory. The program is designed to provide an enjoyable approach to learning Computed Tomography (CT), and is directed toward an audience of medical students, residents, and fellows.

Computer Graphics↗
PubMed1991

CT of posterior mediastinal masses.

This article presents an algorithmic approach to the evaluation of posterior mediastinal masses seen with computed tomography (CT). CT remains the study of choice, since it not only can be used to help confirm the presence of these masses, but it also helps define the (a) location and extent of the lesion, (b) adjacent organ involvement, or (c) vascular involvement. Causes of posterior mediastinal masses include esophageal lesions, congenital or acquired vascular lesions, foregut cysts, intrathoracic goiters, mediastinal pseudocysts, fat-containing tumors, adenopathy, neurogenic tumors, infectious spondylitis, and vertebral tumors. From the CT appearance of the lesion, one can often distinguish among the various masses and identify their origin and cause. This information enables patient triage and therapy to be expedited and, in most cases of posterior mediastinal masses, allows a correct diagnosis to be made solely on the basis of the CT examination.

Blood Vessels↗