Angiographic assessment of dimensions of 6F and 7F Mallinckrodt Softouch coronary contrast catheters from digital and cine arteriograms.

Coronary contrast catheters are almost exclusively used for calibration purposes in quantitative coronary arteriography. In this study we have assessed the suitability of new 6F and 7F Mallinckrodt nylon catheter with Softouch tip with improved imaging specifications for such calibration purposes both from digital and cinefilm images using new analytical QCA-software packages (Philips DCI/ACA and Medis CMS). The average signed differences between the angiographically measured dimensions at 100% contrast fillings and acquired at 3 different kV-levels (60, 75 and 90 kV) were -3.3% and 0.6% for the 6F and 7F catheter tips, respectively as measured with the ACA-package on digital images, and -0.4% and 2.1%, respectively, as measured with the CMS-system on cinefilm images. The pooled standard deviations were 0.102 mm and 0.107 mm for the 6F and 7F catheter tips, respectively, as measured with the ACA-package, and 0.080 mm and 0.083 mm, as measured with the CMS-system. The deviations for the nylon shafts were much larger. It became also clear that neither the filling of the catheters, nor the kV-level used, had any appreciable effect on the measurement accuracy for the Softouch tips, which facilitates the frame selection in QCA-studies. From these data it can be concluded that the nontapering parts of the 6F and 7F Mallinckrodt Softouch tips are very well suitable for QCA calibration purposes, but that the nylon shafts are not.