PERMANENT ELECTRONIC STORAGE OF ANGIOGRAPHIC IMAGES IN THE CATHETERIZATION LABORATORY - HIGH-RESOLUTION AND REAL-TIME ACQUISITION ON OPTICAL LASERDISCS

The use of electronic ''filmless'' media for long-term archiving of co ronary angiograms has been impeded by the problems of image storage an d data transfer among institutions. Although long-term analogue storag e of the images is presently feasible, and much less costly than digit al storage, processing has been limited to a 625 lines video format, n ot optimal for high quality images. We developed a bi-directional 1249 /625 lines converter, able to store and to replay high resolution (124 9 lines) video images, from Component Record Video (CRV) Optical Laser (Analogue) Videodisks. Image quality and medical relevance were evalu ated five ways: 1) Outside experts compared 593 static images stored o n CRV discs to the same images stored in a high-resolution digital for mat blinded to source of image. The four experts found no visual or me dical difference in 98% of evaluated images and minor differences in t he remainder. The differences in the remaining images were not consist ent among experts. 2) Two of the experts also compared the enhanced CR V optically stored image to the image obtained on simultaneously recor ded 35mm cine film, and found the enhanced CRV stored image to be supe rior or similar, but never inferior to the film image. 3) 90 represent atives from 63 outside institutions compared images from both a digita l hard drive and the enhanced CRV optical (analogue) storage displayed at a Windows based digital workstation. During the test they were bli nded as to the source of the images. The representatives found no diff erence in image resolution, quality, diagnostic accuracy, and medical relevance. 4) We evaluated quantitative coronary angiography (QCA) on standard coronary test phantoms using enhanced CRV stored images digit ally processed. The correlation of the enhanced CRV image to the actua l size of the phantom vessels was similar to the results obtained in t he literature from digitally stored images. 5) 78 arterial measurement s ranging 0.65 to 4.85 mm were evaluated both from the digital hard di sc (D) and the CRV optical disc (CRV), using the same QCA analytical p ackage. The correlation coefficient and the Standard Error of the Esti mate between D and CRV values were respectively 0.997 and 0.076, no sy stematic over or underestimation occurred, and the mean variability wa s inferior to 0.1 mm. Conclusion High-Resolution CRV-optical storage r epresents a cost-effective solution for excellent image quality equiva lent to digitally stored images, permitting permanent electronic archi ving inside the cath-lab, and allowing digital image processing and di gital image communication.