“…The various systems used to date vary to a great extent, from manual procedures that implement a vernier caliper or comparable device'2-7 to a computerized manual edge-tracing procedure'8 and methods that make use of computer edge detection algorithms to determine arterial dimensions in a two-dimensional projection. [19][20][21][22][23][24][25][26][27][28][29] Several investigators have also applied densitometric procedures in an attempt to derive crosssectional area measurements from single-view coronary cineangiograms.…”
“…The various systems used to date vary to a great extent, from manual procedures that implement a vernier caliper or comparable device'2-7 to a computerized manual edge-tracing procedure'8 and methods that make use of computer edge detection algorithms to determine arterial dimensions in a two-dimensional projection. [19][20][21][22][23][24][25][26][27][28][29] Several investigators have also applied densitometric procedures in an attempt to derive crosssectional area measurements from single-view coronary cineangiograms.…”
“…The quantitative analysis of selected coronary segments was carried out with the help of a computer-based Coronary Angiography Analysis System (CAAS) that is described in another report in this issue of the journal, as well as extensively elsewhere. [15][16][17][18][19] In short, the boundaries of a selected coronary segment were detected automatically from optically magnified and video digitized portions of a cine frame. Calibration of the diameter data from the vessels in absolute values (mm) was achieved by detecting the boundaries of a section of the contrast catheter and comparing the computed mean diameter in pixels with the known size in millimeters.…”
“…Selzer [l], [2] developed a method of detecting these boundaries based on the first-and secondorder derivatives of the densitometric profile perpendicular to the medial axis ("skeleton") [3]- [5] of the artery image. Similar boundary detection methods were described by Spears [6], Fukui [7], and Kooijman [8]. Because differentiation amplifies the deleterious effects of noise, the profile is smoothed by polynomial curve fitting before the derivatives are estimated.…”
Section: Introduction Lthough the Incidence Of Coronary Artery Dismentioning
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