ANGIOGRAPHIC DETECTION OF GASTROINTESTINAL-BLEEDING - AN EXPERIMENTALCOMPARISON OF CONVENTIONAL SCREEN-FILM ANGIOGRAPHY AND DIGITAL SUBTRACTION ANGIOGRAPHY

RATIONALE AND OBJECTIVES. The authors experimentally assess and compar e the detection limit of gastrointestinal bleeding in digital subtract ion angiography (DSA) and conventional screen-film angiography. MATERI ALS AND METHODS. Arterial blood flow was simulated using a tube model in which bleeding was imitated by exudation of liquid containing contr ast material. Gut peristalsis was imitated using silicone tubes filled with air and liquid, Images ri ere acquired by DSA and conventional s creen-film angiography, The iodine concentration was increased in incr ements from 1 mg I/mL, with and without simulated peristalsis, and wit h both free and circumscribed extravasation of contrast material, RESU LTS. The detection limit for free extravasation in DSA was 1 mg I/mL w ithout peristalsis and 60 mg I/mL with peristalsis, The corresponding figures for circumscribed extravasation were 1 mg I/mL and 34 mg I/mL. The detection limit for free extravasation in screen-film angiography was 172 mg I/mL both with and without simulated peristalsis. Circumsc ribed extravasation was detected at 9 mg I/mL without peristalsis and 7 mg I/mL with peristalsis. CONCLUSION. Digital subtraction angiograph y is the more sensitive angiographic technique for detection of gastro intestinal bleeding and is superior to conventional screen-film angiog raphy, provided that it is performed with adequate parasympathicolysis and suspended respiration. Only when these requirements cannot be ach ieved is screen-film angiography advantageous.