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W J Spyra

Publications and source records attributed to W J Spyra.

2 recordsLinked to original sources

Detection of mild coronary stenoses using the Dynamic Spatial Reconstructor.

The accuracy of the Dynamic Spatial Reconstructor (DSR) in the detection of moderate coronary artery stenoses was examined in 20 closed-chest dogs. Twenty-eight hollow plastic cylinders were embolized into the left coronary arteries and produced 25% to 56% reductions in arterial lumina diameter. For each dog, one three-dimensional (3-D) image of the heart was reconstructed from each DSR scan recorded during injection of contrast into the aortic root. Analysis involved blinded visual analysis by four independent observers of multiview projection images computed from the single 3-D image. Postmortem coronary angiograms of the isolated heart were considered definitive for location of the stenoses. Overall sensitivity of detection by DSR was 89% and specificity 81%. Sensitivity of detecting stenoses greater than or equal to 50% was 98%. Receiver operating characteristics (ROC) analysis showed that detection of stenoses in the left coronary arteries is of equal sensitivity and specificity.

Animals↗

Some technical considerations in tomographic coronary arteriography.

Coronary artery anatomy can be visualized using high-speed, volume scanning x-ray CT. A single scan during a bolus injection of contrast medium provides image data for display of all angles of view of the opacified coronary arterial tree. Due to the tomographic nature of volume image data, the superposition of the vessels on themselves and on other contrast filled coronary arteries, such as would occur in an aortic root injection of contrast agent, can be eliminated. To achieve the goal of coronary arteriography using a single angiographic injection, the tomographic scanner must scan the entire volume encompassing the coronary arteries synchronously and within a brief period of time. The volume must be scanned so that the thickness of the scanned slices is less than the diameter of the smallest vessel desired to be visualized quantitatively. Preliminary results from a fast volume scanning CT scanner (the Dynamic Spatial Reconstructor) used to scan experimental animals are used to indicate the quantitative and qualitative impact of such variables as scanned slice thickness, scanned slice separation and angle between the vessel and the plane of the scanned slices.

Animals↗