Quantification of Ventricular Performance: A Computer‐Based System for the Analysis of Angiographic Data

Abstract

A computer-based quantitative angiography system for the acquisition and analysis of ventriculographic data has been developed. In addition to the apparatus normally required for angiography and left ventricular pressure recording, a digitizing tablet, PDP 11/20 mini computer, and TV monitor with a hard-copy device is employed. Four modes of operation are currently in use: data acquisition, analysis, mini cine, and data tape editor. Data acquisition facilitates forming a magnetic tape record of the digitized pressure, timing, and event identification, together with anywhere from 4 to 100 digitilized LV contours. A number of error checks and feedbacks are incorporated to provide some measure of quality control. In the event an error is written onto the magnetic tape record, the data tape editor can be used to review the record and correct most errors. Analysis of the generated data tape consists of several options which include: pump function, muscle function, pressure derived indices of contractility and systolic time intervals, and contour pattern recognition which is still under development. If the complete analysis option is chosen, a summary of the analysis, referred to as the quick-sight list, is also presented. The so called mini cine option employs a separate and independent acquisition-analysis program. This requires only the end-diastolic (with a segment of wall) and end-systolic contours (without pressure data) to extract the most essential parameters (EDV, EF, CI, HR, and wall mass). As a result of the relative straightforward processing and inherent simplicity, the mini cine option is most frequently used. This system has done much to reduce the time required for analysis of angiographic data, while at the same time maintaining and even improving the quality of the results. Other less tangible benefits include: the possibility to build a readily accessible library of patient data files facilitating a posteriori studies, precise and uniform definition of the rules to input and analyze data, and finally providing a useful step towards fully automatic ventriculographic processing.

Validation of a novel noninvasive cardiac index of left ventricular contractility in patients

“…Numerous studies have shown that, when used properly, such measurements are reliable and reasonably accurate (3,20,34,35). There is no doubt that MR imaging techniques are more accurate and reproducible.…”

Usefulness of digital angiography in the assessment of left ventricular ejection fraction

“…In the CAESAR, left ventricular volume (Vmeas) is also calculated by the area-length method, calibrated in ml on the basis of a calibration sphere, and corrected by Heintzen's formula (LV,,, = 0.72 X V, , , , -4.7 ml) [7]. While the users traced the contours on the DCI, an observer recorded the amount of time needed for this manual procedure, as well as the left ventricular segments which required subsequent manual corrections.…”