Tc-99m dextran: A new and sensitive general purpose scintigraphic agent for diagnosing intestinal inflammation

Purpose: This feasibility study was undertaken to compare the sensitivity o f Tc-99m dextran with that of Tc-99m human immunoglobulin G to diagnose ulc erative colitis, and to explore its possible role in disease followup. Mate rials and Methods: Twenty-six patients with active disease and six patients in remission underwent serial Tc-99m dextran scanning for as long as 3 hou rs or more after injection, Eight of the patients with active disease also underwent Tc-99m human immunoglobulin G imaging, Results: Twenty-four of 26 (92%) patients with active ulcerative colitis ha d a positive result of the Tc-99m dextran study, mainly within 1 hour, In c omparison, Tc-99m human immunoglobulin G accumulated abnormally in four of eight (50%) patients and had a relatively poor target localization with hig h persisting background even after 6 hours, Four of the six patients in rem ission still had a positive result of the dextran scan, but the abnormal up take was less than that in the patients with active disease, The disease ha s recurred already in one of these patients, A patient with pancolitis who was receiving steroid enema therapy had intense uptake of Tc-99m dextran in the ascending colon, probability because it was outside the range of the e nema, Conclusions: Tc-99m dextran is a sensitive and cost-effective agent to diag nose ulcerative colitis, and it may have a role in disease follow-up.