Improved angiographic measurement accuracy with a new calibration system

During transcatheter interventions, correct distance measurements are manda tory for proper device selection. We present a new calibration procedure in which distance calibration is performed with a high contrast metallic rod placed in the esophagus as a scaling device. Distortion related to differen ces in calibration and object planes as well as axial angles were analyzed and appropriate correction factors calculated A cardiac phantom sewed to te st the accuracy and precision of the new measuring system. The mean measure ment error was < 1.7% (range 0.1%-4.9%), and the mean measurement variabili ty 1% (range 0.3%-1.9%). The accuracy of angiographic measurements can be s ignificantly improved using a calibration device in the esophagus in combin ation with appropriate mathematical corrections.