Three-dimensional display of the heart, aorta, lungs, and airway using CT.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
E K Fram
Publications and source records attributed to E K Fram.
Reconstruction of imperfectly ordered zinc-induced tubulin sheets using cross-correlation and real space averaging.
Large negatively-stained two-dimensional tubulin arrays induced by incubation with zinc were examined using electron microscopy. When Fourier methods are applied for the reconstruction, the resolution depends critically on the order of these arrays. The real space cross-correlation method as described in this paper, however, can be satisfactorily applied to disordered arrays. The method involves selection of a small area which is used as a reference to locate correlation peaks in other regions. In this way the locations of various unit cells are determined, often at points which deviate from the exact lattice. The unit cells at their determined locations are averaged, and the average is used as an improved reference in another search for correlation peaks. The process can be iterated to refine the reference and improve the correlation mapping. If necessary, poorly correlating unit cells can be ignored in the averaging, and rotational as well as translational corrections can be considered; but neither of these steps were found to be necessary in the studies on the zinc-induced tubulin sheets reported here. When both correlation and Fourier methods were compared for the same areas of selected sheets, the two methods gave comparable results for relatively well ordered regions, but the correlation images were superior for the more poorly ordered regions. In addition, even for the relatively well ordered regions the correlation images revealed some details that were lacking in the simple Fourier reconstructions but did appear in more extensive studies involving three-dimensional reconstruction. A direct comparison of the efficacy of real space and Fourier space reconstruction methods is presented using disordered model data.
Fourier Analysis↗
A phantom for testing ECG-gated computed tomography of the heart.
A mechanical phantom has been built to evaluate electrocardiographically gated computed tomography of the heart. The phantom simulates the heart in terms of cyclic changes in chamber dimensions and wall thickness. Rate and excursion are variable, and the cavity of the chamber can be filled with liquid contrast media of different degrees of radio-opacity. Preliminary experiments with a prototypic gating system are described.
Electrocardiography↗
Three-dimensional reconstruction of tubular myelin.
The lipid and protein components of pulmonary surfactant are synthesized by alveolar type II cells and stored in their secretory granules, the lamellar bodies. Tubular myelin is a highly ordered surfactant structure that is lung specific and produced in the alveolar airspace. Recent work identified Ca2+, surfactant apoproteins A and B, and saturated phospholipids as necessary for tubular myelin structure and function. We have used serial ultrathin sections from fetal rat lungs and reconstructed the three-dimensional structure of tubular myelin. The spheres of tubular myelin we viewed were 2-3 microns in diameter and were surrounded by up to 20 lamellar bodies, each apparently simultaneously contributing material to the tubules. We measured a long-range symmetry of the tubules, which were folded about a central axis and showed a repeated crossing of individual tubes from one side to the other of the large structure. The tubes appeared closed on their outer edges and there was a delay in the penetration of tubules by cationic ferritin added to tissue slices containing the tubular myelin, although within a few minutes tracer appeared in the lumina and on the walls of the tubules. The three-dimensional images were compatible with existing views of tubular myelin.
Animals↗
MR angiography of cervical fibromuscular dysplasia.
The authors present examples of cephalic fibromuscular dysplasia (involving five vessels in two patients) using 2-D time-of-flight MR angiography and conventional angiography. Artifacts that can mimic the MR appearance of fibromuscular dysplasia will tend to decrease the sensitivity and specificity of MRA in its detection.
Angiography↗
Highlights of the 29th annual meeting of the American Society of Neuroradiology, Washington, DC, June 9-14, 1991.
Explore the source record for details and available documents.
Acquired Immunodeficiency Syndrome↗
Examination of the extracranial carotid bifurcation by thin-section dynamic CT: direct visualization of intimal atheroma in man (Part 1).
Because carotid angiography has been shown to have limitations in the detection of intimal disease at the bifurcation, a new method of examination of the extracranial carotid artery has been developed using thin-section dynamic computed tomographic (CT) scanning. Carotid atheroma and thrombi can be imaged directly on these sections. The intimal lesions are uniformly hypodense with respect to the carotid arterial wall. Radiologic-pathologic correlation studies using human carotid arteries in a neck phantom confirm that these hypodense lesions are atheromas or thrombi. There is good correlation between CT cross-sectional images and cross-sectional postmortem artery sections. While a number of new computer-based methods of reformation of the carotid artery have been developed, consecutive thin slices through the carotid bifurcation display the pathologic lesions satisfactorily.
Carotid Arteries↗