Gastrointestinal examinations with a 2,048-×2,048-pixel image intensifier television digital radiography system

Abstract

The clinical usefulness of a 2,048-x 2,048-pixel matrix image intensifier television digital radiography system was evaluated. Screen-film and digital images (with and without postprocessing) of the upper and Iower gastrointestinal (GI) tract were used for clinical evaluation. For the upper GI tract, digital images processed with unsharp mask techniques were comparable in quality to screen-film images before and after upgrading the system. For the Iower GI tract, screen-film images were better than digital images, except for those processed with a 2,048-x 2,048-1ine monitor was comparable to a screen-film system. Copyright 9 1995 by W.B. Saunders Company KEY WORDS: digital radiography, image intensifier television digital radiography, gastrointestinal examination, cathode-ray tube diagnosis.T HE DIGITAL RADIOGRAPHY system, using an image intensifier television (II TV) system, provided advantages over conventional screen-film radiography in data acquisition, transmission, processing, and instant display. 1-3 However, critical limitations of II TV digital system include lower spatial resolution and smaller imaging fields. 4-6 Although several approaches have been attempted to solve these problems, TM resolution properties of the II TV digital system currently used are still lower compared with conventional screen-film systems, and detection ofvarious subtle abnormalities are limited in clinical examinations.We have reported on development of a highresolution II TV digital system with a 2,048-x 2,048-pixel matrix image intensifier. 43 We have recently upgraded the system with a new TV camera and an x-ray tube with a 0.3-mm focal spot and reported the basic properties and clinical usefulness of the new system for gastrointestinal (GI) examinations before and after upgrading. 8-a~In this report, the usefulness of cathode-ray tube (CRT) diagnosis, including multi-image display and the cost of image storage is also discussed. II TV DIGITAL RADIOGRAPHY SYSTEMMajor components of our new system consisted of a TV camera, a triple-mode (12-, 9-, and 7-in) II, an image processor, two TV monitors, laser printers, and an image file with a large memory capacity. 4 The analog digital converter has a capability of 10-bit conversion at a tate of 20 MHz. Images can be acquired in the image matrix sizes of 1,024 x 1,024 and 2,048 x 2,048 pixels on each mode of II.Each acquired image was processed automatically by a number of digital-processing algorithms, including unsharp masking technique, t ~-~~ and instantly displayed on TV monitors with 1,024-x 1,024-and 2,048-x 2,048-pixel matrices, followed by transfer to hard copies and digital storage.The distance between the focal spot and the table top was 100 cm for fluoroscopic (digital) examinations. The distance between the screenfilm and the table top was 5 cm, whereas the distance between the II and the table top was 15 cm. Conventional screen-film radiography was obtairted using medium-speed screen-film systeta placed in front of the II surface. COMPARISON OF DIGITAL IMAGES WlTH SC...