GI Bleeding Scan

1. GI Bleeding Scan รศ.พญ. มลฤดี เอกมหาชัย หน่วยเวชศาสตร์นิวเคลียร์ ภาควิชารังสีวิทยา คณะแพทยศาสตร์ มหาวิทยาลัยเชียงใหม่

2. GI Bleeding 1. Upper GI bleeding 2. Lower GI bleeding

3. Diagnostic Procedures 1. Endoscopic examination 2. Selective angiography 3. GI bleeding scan

4. Acute Lower GI Bleeding 1. Small bowel bleeding 2. Large bowel bleeding

5. Causes of Small Bowel Bleeding • Regional enteritis • Intestinal varices • Lymphoma • Heriditary telangiectasia • Meckel’s diverticulum etc.

6. Causes of Large Bowel Bleeding • Diverticulosis • Inflammatory diseases • Arteriovenous malformation • Angiodysplasia • CA colon, Polyps etc.

7. Acute Lower GI Bleeding 1. Rigid endoscopy (Proctosigmoidoscopy) 2. Selective angiography 3. GI bleeding scan

8. Algorithm for the Dx & Rx of Acute Lower GI Hemorrhage Acute Lower GI Bleeding Proctosigmoidoscopy Rectal fissure, Bleeding site not found Hemorrhoids, Polyps or CA etc. GI bleeding scan Surgery or Therapeutic angiography

9. Algorithm for the Dx & Rx of Acute Lower GI Hemorrhage GI bleeding scan Positive scan Negative scan Angiography , Medical treatment Transcatheter Rx Elective colonoscopy Persistent bleedingBarium studies, CT etc Surgery

10. GI Bleeding Scan 1. Tc99m-Sulfur Colloids 2. Tc99m-labeled Red Blood Cells

11. Tc99m-Sulfur Colloid Scan • Dose 10 mCi IV • Circulation half-time 2.5-3.5 min • Active bleeding within 15-30 min • Minimal bleeding rate 0.05-0.1 ml/min

12. Mechanism • To demonstrate an acute GI bleed • Extravasation of activity (increased uptake)

14. Time-Activity Curves

15. Negative Tc99m- Sulfur Colloid Scan • Normal uptake in - Liver - Spleen & - Bone marrow

16. Positive Tc99m- Sulfur Colloid Scan • Normal uptake in liver, spleen & bone marrow • Extravasated activity at bleeding site(s)

17. Tc99m-labeled Red Blood Cell Scan • Dose 20 mCi IV • Active or intermittent bleeding • Minimal bleeding rate 0.35 ml/min

18. Negative Tc99m-RBC Scan • High uptake in - Blood pool organs & - Great vessels of abdomen

19. Positive Tc99m-RBC Scan • Normal uptake in blood pool organs & great vessels • Extravasated activity at bleeding site(s)

20. Scintigraphic Criterias for Dx of GI Bleeding 1. Area(s) of extravasated activity (increased uptake) - Appearsand - Conforms to bowel anatomy

21. Scintigraphic Criterias for Dx of GI Bleeding • 2. Area(s) of extravasated activity - Persistence or - Increased in intensitywith time

22. Scintigraphic Criterias for Dx of GI Bleeding 3. Area(s) of extravasated activity can change in - Size - Configuration & - Location with time.

23. Scintigraphic Criterias for Dx of GI Bleeding 4. Area of extravasated activity does not initially present, but appears in later images.(intermittent bleeding)

24. Advantages of GI Bleeding Scan • Noninvasive • More sensitive • Low cost • Low radiation exposure • Active or intermittent GI bleeding • Venous or arterial bleeding

25. Dose 20 mCi IV More complicated Noninvasive Low radiation exposure Lower target/nontarget ratio Active or intermittent bleeding Bleeding rate >0.35 ml/min Venous or arterial bleeding Dose 10 mCi IV Simple Noninvasive Low radiation exposure Higher target/nontarget ratio Active bleeding Bleeding rate > 0.1 ml/min Venous or arterial bleeding Tc99m-RBCTc99m-S.Colloid

26. Negative Tc-99m Sulfur Colloid Scan

28. Small Bowel Bleeding

30. Terminal Ileal Bleeding

31. 10 min 20 min

32. Ascending Colon Bleeding 10 min 20 min

33. 5 min 30 min

34. Ascending Colon Bleeding 5 min 30 min

36. Mid Descending Colon Bleeding

38. Descending Colon Bleeding

40. Sigmoid Bleeding

42. Rectal Bleeding

43. Negative Tc-99m RBC Scan 5 min 15 min 30 min 1 hour

44. Blood pool image Dynamic study 2sec/Frame

46. Active Jejunal Bleeding

47. 1 hr 2 hrs 3 hrs 4 hrs

48. Small Bowel Bleeding 1 hr 2 hrs 3 hrs 4 hrs

49. 45 min 1 hour 2 hrs 3 hrs

50. Small Bowel Bleeding 45 min 1 hour 2 hrs 3 hrs