1. 1 NM 4203 Scanning & Imaging Gastrointestinal System

2. 2 Alimentary Canal Mouth Pharynx Esophagus Stomach Small intestine Large intestine (colon)

3. 3 Accessory Organs Salivary glands Pancreas Liver Gallbladder

4. 4 Stomach Anatomy & Physiology Three Regions: –Fundus : controls liquid emptying –Corpus (body) –Antrum : controls solid emptying

5. 5 Gastric Emptying Study Indications –Nausea, vomiting –Weight loss –Abdominal bloating Mechanical causes –Ulcer, tumor, post-radiotherapy, pyloric stenosis, post-surgical Nonmechanical causes –Diabetes, hypo or hypertension, neuropathy, gastroparesis, anorexia, amyloidosis

6. 6 Gastric Emptying Study Each lab must standardize meal type and size. Solid phase could be meat, chicken liver, eggs, french toast, etc ( 99m Tc Sulfur Colloid) Liquid phase could be water, orange juice, apple juice. ( 111 In DTPA)

7. 7 Gastric Emptying Study Patient fasting for at least 8 hrs. Medium energy collimator (if doing liquid phase with In 111 DTPA) Should eat meal within 5 minutes, followed by liquid.

8. 8 Liver Anatomy & Physiology Right upper quadrant of abdomen Right lobe generally larger than left Composed of: –Kupffer cells –Hepatocytes Conversion of bilirubin to bile Spleen: not part of the GI system

9. 9 Liver – Spleen imaging 99m Tc Sulfur Colloid or 99m Tc Albumin Colloid Can do a flow (looking at vascularity of some defects) No pt. prep Static images 15 min. after injection –Anterior, RAO, Rt lat, RPO, posterior, LPO, Lt lat, LAO

10. 10 Liver – Spleen Colloid Image

11. 11 Liver Hemangioma 99m Tc – Labeled Red Blood Cells No pt. prep Bolus 15 – 25 mCi with immediate flow imaging Followed by pool images per facility protocol SPECT usually 2-3 hours after injection.

12. 12 Liver Hemangioma

13. 13 Liver Hemangioma Little or no blood flow to the lesion on early flow images Delayed imaging usually shows increased uptake in hemangioma. Other types of lesions will retain RBC’s, but only hemangiomas retain RBC’s for over 2 hrs. Some consider this test to be 100% accurate for Hemangioma detection.

14. 14 Gallbladder Anatomy & Physiology Concentrates and stores bile Stimulated by fatty meal to contract and release bile into the duodenum Bile is useful to breakdown fats during digestion.

15. 15 Extrahepatic biliary anatomy

16. 16 Hepatobiliary Imaging Radiopharmaceuticals – 99m Tc HIDA, 99m Tc DISIDA, 99m Tc Mebrofenin Pt. should fast at least 2 hrs. before study, no more than 24 hrs. Pain medications (opium or morphine based) should not be taken prior to imaging. Rt. Lateral image is helpful to separate Gb (Gallbladder should be anterior to other structures)

17. 17 Acute Cholecystitis Usually due to cystic duct obstruction Visualization of GB with radiopharmaceutical excludes diagnosis of acute cholecystitis No GB visualized in 4 hrs, high probability of acute cholecystitis

18. 18 Acute Cholecystitis

19. 19 Gallbladder Imaging: other medications Cholecystokinin (CCK) –Causes gb contraction –Relaxes the sphincter of Oddi –Used for GB Ejection Fraction –Peptide hormone, naturally secreted by duodenum Morphine –Decreases peristalsis –Constricts the sphincter of Oddi –Used when Gb is not visualized to “force” radiopharmaceutical into the gb.

20. 20 Biliary Leak Usually requested after surgery or trauma Subtle leaks that may accumulate in the pelvis May mimic a gb ~ labeled bile in the gallbladder fossa

21. 21 Intestine anatomy & physiology Small intestine –Duodenum, jejunum, and ileum –20 feet long –Digestion and absorption of nutrients Large intestine –Cecum, ascending colon, transverse colon, descending colon,sigmoid colon, and rectum. –Resorption of water

22. 22 GI Bleed Imaging Radiopharmaceutical –99mTc Sulfur Colloid or 99mTc –labeled RBC’s (each facility may have different labeling method) Bolus injection with immediate flow imaging

23. 23 GI Bleed

24. 24 Causes of GI Bleeding Diverticular disease Angiodysplasia Neoplasms Inflammatory bowel disease Not uncommon to never find a reason

25. 25 Meckel’s Diverticulum Common cause of GI bleeding in children. Most are located in the ileum 99m Tc Pertechnetate ~ concentrates in gastric mucosa

26. 26 Meckel’s Diverticulum Painless rectal bleeding More common in children Some Meckel’s do not contain gastric mucosa, won’t show on scan Glucagon – given i.v. 10 minutes after Tc injection or Zantac given i.v. prior to Tc injection –Decrease small bowel activity

27. 27 Schilling Test GI absorption of vitamin B 12 57 Co vitamin B 12 given orally Followed by IM injection of non-labeled vitamin B 12 (saturates the liver) Urine collected for 24 hrs.