Büchi M, Hess O M, Kirkeeide R L, Suter T, Muser M, Osenberg H P, Niederer P, Anliker M, Gould K L, Krayenbühl H P
Department of Internal Medicine, Medical Policlinic, Cardiology, University Hospital, University of Zürich.
Int J Card Imaging. 1990;5(2-3):93-103. doi: 10.1007/BF01833978.
In a collaboration between the University of Texas (software) and the University of Zürich (hardware) a compact, automatic system for biplane quantitative coronary arteriography was developed. The system is based on a 35 mm film projector, a slow-scan CCD-camera (image digitizing) and a computer workstation (Apollo DN 3000, image storage and processing). A new calibration procedure based on two fixed reference points in the center of the image intensifier was used (isocenter technique). Contour detection of coronary arteries was carried out in biplane projection using a geometric-densitometric edge-detection algorithm. The proximal and distal luminal areas, as well as the minimal luminal area of the stenotic vessel segment were determined. Accuracy and precision were determined from precision drilled holes in a plexiglas cube which were filled with 50%, 75% and 100% contrast medium. The diameter of the holes ranged from 0.5 to 5.0 mm. The mean difference and the standard deviation of the differences between the true and the measured diameters were 0.12 +/- 0.14 mm for plane A and 0.26 +/- 0.17 mm for plane B, respectively. After a second order correction the mean difference amounted to 0.02 +/- 0.09 mm for plane A and 0.02 +/- 0.12 mm for plane B, respectively. Intra- and interobserver variability were evaluated in 5 patients (age 60 +/- 10 years) with coronary artery disease using 16 normal and 5 stenotic vessel segments (cross-sectional area ranging from 0.8 to 8.7 mm2). Two independent observers analyzed the same vessel segment twice. Intraobserver variability expressed as the standard error of estimate in percent of the mean angiographic vessel area (SEE) amounted to 2.1% for observer 1 and 4.4% for observer 2, respectively. Interobserver variability expressed as SEE was 4.1% for measurement 1 and 3.6% for measurement 2, respectively.
德克萨斯大学（软件方面）与苏黎世大学（硬件方面）合作开发了一种用于双平面定量冠状动脉造影的紧凑型自动系统。该系统基于一台35毫米胶片投影仪、一台慢扫描电荷耦合器件相机（图像数字化）和一个计算机工作站（阿波罗DN 3000，图像存储与处理）。采用了一种基于图像增强器中心两个固定参考点的新校准程序（等中心技术）。使用几何密度边缘检测算法在双平面投影中进行冠状动脉轮廓检测。确定了狭窄血管段的近端和远端管腔面积以及最小管腔面积。通过在充满50%、75%和100%造影剂的有机玻璃立方体中精确钻孔来确定准确性和精密度。孔的直径范围为0.5至5.0毫米。平面A中真实直径与测量直径之间的平均差异及差异的标准差分别为0.12±0.14毫米，平面B为0.26±0.17毫米。经过二阶校正后，平面A的平均差异分别为0.02±0.09毫米，平面B为0.02±0.12毫米。使用16个正常和5个狭窄血管段（横截面积范围为0.8至8.7平方毫米）对5例（年龄60±10岁）冠心病患者的观察者内和观察者间变异性进行了评估。两名独立观察者对同一血管段进行了两次分析。观察者1的观察者内变异性以估计标准误差占平均血管造影血管面积（SEE）的百分比表示，分别为2.1%，观察者2为4.4%。测量1的观察者间变异性以SEE表示为4.1%，测量2为3.6%。
