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Biomedical subjects

L T Cook

Publications and source records attributed to L T Cook.

28 records · Page 2Linked to original sources
PubMed1982

Three-dimensional computer reconstructions of brain lesions from surface contours provided by computed tomography: a prospectus.

We present a prospectus on the use of computer graphics for the three-dimensional reconstruction and visualization of brain lesions from computed tomographic head examinations, including an algorithm that utilizes surface contour information to reconstruct and display three-dimensional anatomical sites. We provide examples of the use of this algorithm. We offer an algorithm for estimation of the volume and surface area of anatomical sites. The advantages and disadvantages for the clinical use of these algorithms are discussed.

Adenoma, Chromophobe↗
PubMed1981

Three-dimensional computer reconstruction from surface contours for head CT examinations.

A three-dimensional surface reconstruction algorithm based on contour information from anatomic sites as identified on computed tomography examinations is presented. This algorithm efficiently reconstructs the surfaces between the contours using a triangular "tiling" method. A three-dimensional perspective view of the reconstructed surfaces is provided by a gray scale cathode-ray tube computer graphics system. Volume and surface area estimations are provided as a direct results of the surface reconstruction algorithm. Three cases are presented to illustrate the three-dimensional surface reconstruction algorithm.

Brain Neoplasms↗
PubMed1981

Measurement accuracy of proximal femoral geometry using biplanar radiography.

Experimental testing indicates that the neck-shaft angle of the proximal femur can be reliably measured from biplanar radiographs, but torsion cannot. Calculated torsion varies significantly from true torsion as a function of the error created by femoral rotation, while the calculated neck-shaft angle is invariant with respect to rotation even though the calculated neck-shaft angle is mathematically dependent on calculated torsion. Theoretical considerations support this finding and demonstrate for the first time why it is true. This study demonstrates that clinical measurements of frontal plane hip deformities using existing biplanar radiography are quite accurate, but clinical measurements of torsional abnormalities are unreliable. These errors can be minimized if investigators specify the angle of the lateral X-ray beam on the anteroposterior film using methods described in this paper and if patient position is radiographically verified. The magnitude and types of errors inherent in biplanar radiography should be considered in planning preoperative strategies and in postoperative assessments of hip geometry.

Femur↗
PubMed1980

The use of computer imaging techniques to visualize cardiac muscle cells in three dimensions.

Atrial muscle cells and atrioventricular bundle cells were reconstructed using a computer-assisted three-dimensional reconstruction system. This reconstruction technique permitted these cells to be viewed from any direction. The cell surfaces were approximated using triangular tiles, and this optimization technique for cell reconstruction allowed for the computation of cell surface area and cell volume. A transparent mode is described which enables the investigator to examine internal cellular features such as the shape and location of the nucleus. In addition, more than one cell can be displayed simultaneously, and, therefore, spatial relationships are preserved and intercellular relationships viewed directly. The use of computer imaging techniques allows for a more complete collection of quantitative morphological data and also the visualization of the morphological information gathered.

Animals↗
PubMed1980

A radiographic method for three-dimensional analysis of spinal configuration.

Current two-dimensional methods for quantifying scoliosis are inadequate. A radiographic method has been developed which determines the three-dimensional location and rotation of each vertebra. Posteroanterior and posterior oblique radiographs of the spine are obtained with the patient standing within a reference frame. Computerized analysis of these radiographs provides a complete quantitative description of spinal configuration. Using this information, scoliosis progression may be more accurately predicted, and therapeutic measures can be more thoroughly analyzed utilizing biomechanical principles.

Computers↗
PubMedDate not supplied

Three-dimensional analysis of right thoracic idiopathic scoliosis.

Three-dimensional spinal analysis was performed on thirty-one female patients with untreated right thoracic idiopathic scoliosis to determine the relationship between the degree of scoliosis and the degree of kyphosis, maximal curvature, and apical vertebral displacement. The degree of scoliosis did not correlate with the degree of thoracic kyphosis. Six patients had thoracic kyphosis over 50 degrees, 19 patients had a kyphosis between 20-50 degrees, and the last six patients had a thoracic kyphosis less than 20 degrees. The apex of the scoliosis was at or below the apex of the thoracic kyphosis in all patients except one. The degree of displacement of the apical vertebrae had a positive correlation (r = 0.732) with the degree of scoliosis. The maximal curvature of the spine was correlated (r = 0.613) with the degree of scoliosis.

Adolescent↗
PubMedDate not supplied

High-resolution digital x-ray detector utilizing a discrete array of CdWO4 scintillators and a self-scanned photodiode array.

A high-resolution x-ray detector array for x-ray imaging is described. It consists of a discrete array of CdWO4 scintillators and a Reticon 1024S photodiode array with a fiber-optic faceplate. The scintillator elements measure 0.099 X 3 X 4 mm and are bonded together with aluminum foil separators to minimize light crossover. Detective quantum efficiency (DQE) of individual detector channels was 0.38. Systematic variations between channels were substantial. With only a simple correction for between channel variations, DQE for the entire array was 0.04. Evaluation of the edge response function of the array showed that resolution is similar to a detector whose line spread function is Gaussian with a standard deviation of 0.172 mm.

Cadmium↗