Detection of the fluorescence of GI vessels in rats using a CCD camera or a near-infrared video endoscope

Background: Choroidal near-infrared fluorescent angiography can detect vess els in the eye with high resolution. Observation of fluorescent gastrointes tinal (GI) vessels by endoscopy may be useful in portal hypertension and bl eeding ulcer. We here describe a technique for the detection of fluorescent GI vessels with a CCD camera or a near-infrared video endoscope. Methods: Laparotomy was performed on rats. A tissue target was excited by m eans of a laser diode. We took pictures of tissue under both white and near -infrared light, both before and after intravenous injection of indocyanine green. Fluorescent light was selected by means of filters placed in front of the lens of a CCD camera or a near-infrared video endoscope. Results: Under near-infrared light and after dye injection, we observed flu orescent vessels in real time and distinguished arterial from venous fluore scence. Conclusions: This device permits visualization of GI vessels, which could b e useful for diagnosis of vascular abnormalities during endoscopy and surge ry.