Quantitative coronary analysis (QCA) is a technique that is rarely used because of the complexity and expense of existing systems. We studied a new personal computer-based QCA system that is capable of both geometric and densitometric analysis and compared it to a previously validated QCA system. Both systems performed extremely well in phantom analysis with 11 phantoms filmed in both 5-inch and 7-inch magnifications (R greater than 0.97 and SEE less than 0.33 mm for all modes). In 28 abnormal coronary angiograms analyzed at end diastole, stenosis and reference diameter correlations between the two systems were excellent (R = 0.90 and 0.96 and SEE = 0.43 and 0.33 mm for densitometric and geometric modes, respectively). Intraobserver and interobserver correlation was also excellent for both analysis modes. The new QCA system was able to perform analysis in approximately one third the time required by previously validated system and was much less expensive. We conclude that personal computer-based coronary analysis is an accurate, quick, and relatively inexpensive means for performing QCA that may help to make this technique feasible for nonresearch settings.