99mTc-DTPA uptake in malignant and inflammatory bowel disease: experience from gastrointestinal bleeding studies

During the evaluation of 99Tcm-DTPA for localization of acute gastrointestinal bleeding in 81 studies (78 patients), it was observed that there was an increased 99Tcm-DTPA at sites of inflammatory and malignant lesions of the GI tract in 18 studies. Active bleeding was detected only in 10 and no bleeding was detected in the remaining eight studies. In all the increased DTPA uptake helped to localize the site of bleeding. Image subtraction of early from delayed images according to a predefined acquisition and processing protocol helped to differentiate bleeding from non bleeding lesions. We conclude that increased 99Tcm-DTPA uptake in malignant and inflammatory lesions of the bowel is an additional advantage for its use in localizing the site of acute GI bleeding. Technetium-99m diethylenetriamine pentaacetic acid (99Tcm-DTPA) has been widely used for imaging the brain and kidneys since it was introduced by Hauser in 1970. Kadir and Strauss in 1979 reported that 99Tcm-DTPA localizes in segments of bowel with inflammation due to ulcerative colitis, regional enteritis and other forms of enterocolitis. Recently we reported the advantages of 99Tcm-DTPA in localizing the site of acute gastrointestinal bleeding. Inflammatory bowel diseases are among the causes of gastrointestinal bleeding. One of the problems in localizing the site of the bleeding by radionuclide procedures is the intermittent nature of the bleeding. We have reviewed all gastrointestinal bleeding studies in our department using 99Tcm-DTPA from January 1984 till September 1985 in order to find out whether increased uptake of 99Tcm-DTPA was helpful in localizing the bleeding lesion due to malignancy and/or inflammation.