Colon Transit Scintigraphy by 67Ga-citrate for Idiopathic

Background/Objective: Segmental colonic transit studies are important in patients with severe constipation. This study is the first Iranian preliminary survey of colonic transit scintigraphy using 67Ga-citrate as a new method in constipated patients with normal radiographic and colonoscopic evaluations. Patients and Methods: Thirteen patients with idiopathic constipation underwent colon transit scintigraphy. After oral administration of 6-7 MBq 67Ga-citrates, serial abdominal images were taken up to 72 hours. Pattern classification wa s performed visually according to the distribution of radioactivity. Scintigraphic parameters such as geometric mean center (GMC) of segmental retention of tracer, as well as mean ac tivity profiles and colo nic tracer half-clearance time were calculated Results: Three patterns of colonic transit scintigraph y were recognized. Nine patients had the normal pattern, i.e. excellent propagation of ac tivity. Three patients had the colonic inertia pattern with marked retention of activity in th e transverse colon and splenic flexure at 48 hours. One patient had significant retention of activity in the rectosigmoid at 72 hours, defined as functional rectosigmoid obstruction (FRSO). No significant difference was seen in GMC24h between the normal pattern and colonic inertia (P=0.053), but GMC48h and GMC72h markedly differed between the two groups (P=0.0 16 and 0.025 respectively). The mean half clearance time (MCT) of the two groups was di fferent (P=0.017). Our results are well compatible with scintigraphic diagnostic criteria in different patterns of colonic transit defined by other studies with different radiotracer. Conclusion: Oral 67Ga-citrate colon transit scintigraphy is a feasible method to evaluate idiopathic constipation and seems to be a suitable surrogate for radio-opaque markers.