Radiography of the GI System

1. Radiography of the GI System Chapter 17

2. Anatomy Of Digestive System • Alimentary Canal • Mouth • Pharynx • Esophagus • Stomach • Small / Large Intestine

3. Anatomy Of Digestive System • Accessory glands • Liver • Gallbladder • Salivary glands • Pancreas

4. Esophagus • Long muscular tube carries food and saliva from laryngopharynx to stomach • Approximately 10 in. long in adult • Lies in midsagittal plane

5. Esophagus • Originates around C-6 • In thorax, it is anterior to spine, posterior to trachea and heart • Passes through diaphragm through esophageal hiatus

6. Esophagus • Inferior to diaphragm curves sharply left • Increases in diameter • Joins stomach at esophagogastric junction • At level of xyphoid tip • 4 layers of the esophagus • Outermost - fibrous • Muscular • Submucosal • Innermost - Mucosal

7. Stomach • Dilated saclike portion of digestive tract • Composed of same 4 layers as esophagus • Outermost - fibrous • Muscular • Submucosal • Innermost - Mucosal

8. Stomach (cont’d) • Divided into 4 parts • Cardia • Fundus • Body • Pyloric portion • Entrance to stomach is cardiac orifice • Controlled by cardiac sphincter • Exit is the pyloric orifice • Controlled by pyloric sphincter

9. Stomach (cont’d) • Body • Begins at cardiac notch • Contains rugae • Terminates at angular notch • Pyloric portion • Consists of pyloric antrum and canal • (antrum: cavity or chamber)

10. Body Habitus - Effect On Positioning • Hypersthenic • Horizontal and superior • Dependent portion above umbilicus • Asthenic • Vertical and inferior • Sthenic • Generally found between xyphoid process and iliac crest

11. Functions Of Stomach • Breaks down food chemically • Broken down material is called? • chyme • A storage area for further digestion

12. Small Intestine • Extends from pyloric sphincter to ileocecal valve • Joins large intestine at right angle • Digestion and absorption of food occur in small intestine • Approximately __ feet in length in adult • 22

13. Small Intestine • Contains same four layers as stomach and esophagus • Mucosa contains projections called villi to facilitate digestion and absorption • Divided into 3 parts: • Duodenum • Jejunum • Ileum

14. Duodenum • 8 - 10 inches in length • Widest portion of small intestine • Follows a C-shaped course • Contains 4 regions • Superior, descending, horizontal, ascending

15. Jejunum And Ileum • Jejunum • Upper remaining 2/5 of small bowel • Ileum • Terminates at ileocecal valve • Both are gathered into freely movable loops (gyri) • Attached to posterior abdominal wall by mesentary • (the double layer of peritoneum)

16. Valvulaeconniventes Muscular bands encircling small bowel usually seen to traverse bowel wall at right angles to long axis of the bowel

17. Large Intestine • What is the main purpose? • Reabsorbs fluids and eliminate waste products • About _____ feet in length in adult • 5 • Greater in diameter than small intestine • Contains same four layers as esophagus, small intestine, and stomach • Which are?

18. Portions Of Large Intestine • Cecum • Ascending • Joins transverse colon at right colic flexure • Transverse • Descending • Joins transverse colon at left colic flexure • Sigmoid • Rectum • Anal canal

19. Large Intestine • The muscular portion contains external bands of muscle known as taeniae coli • These bands create a series of pouches known as? • haustra

20. Compare Valvulae conniventes Small bowel Haustra Large bowel

21. Variations In Body Habitus • Hypersthenic • Colon lies in periphery of abdomen • May need double films! • Asthenic • Intestines are bunched together in lower abdomen

22. Radiographic Exams

23. Contrast Media • Barium sulfate • Water insoluble • Iodinated contrast media • Water soluble • Horrible taste • Does not adhere to wall of alimentary tract • Indicated in case of perforation

24. Contrast Media • Air • Considered a negative contrast • Generally administered by carbon dioxide crystal ingestion • Barium and Air are often used as a double contrast agent

25. Preparing pt. for GI study Have contrast agents mixed and ready to go Explain exam to pt. Ensure pt. has followed preparation instructions!

26. Preparation cont’d Ensure that footboard is securely on table! Use short exposure times Use high kVp to penetrate barium Take exposures end of full expiration!

27. Radiography Of Esophagus • Can use double or single contrast • Barium should flow to sufficiently coat esophagus • Can be done upright or recumbent • Exam will usually be started with fluoroscopy

28. AP or PA Projection • Pt. supine or prone • Center midsagittal plane to cassette • Bottom of cassette should be placed just below tip of xyphoid • Pt. drinks contrast before exposure and continues drinking during exposure • Shield!

29. RAO or LAO Positions • Pt should be rotated 35 - 40 degrees • Center about 2 inches lateral to MSP • Bottom of cassette below xyphoid

30. RAO or LAO Positions Pt must drink before and during exposure Use shielding!

31. Lateral Projection • Place pt in lateral position • Center midcoronal plane to cassette • Bottom of cassette below xyphoid process • Pt must drink continuously before and during exposure • Use shielding!

32. Structures Shown/Film Evaluation • Entire barium filled esophagus from lower neck to stomach • Barium should be sufficiently penetrated • Surrounding structures should be visible, not overpenetrated • No rotation on AP, PA, or lateral projections • Esophagus should be displayed between heart and spine on oblique projections

33. What is the Valsalva Maneuver? • Useful in demonstrating esophageal varices • Have pt. first deeply inspire • Swallow contrast • Bear down • Recumbent position

34. Esophageal varices Extremely dilated sub-mucosal veins in the lower esophagus Most often a consequence of portal hypertension, commonly due to cirrhosis Pts with esophageal varices have a strong tendency to develop bleeding

35. Radiography Of The Stomach Upper GI Series • Generally consists of fluoroscopy and serial radiographs • Single or double contrast • Pt. should follow a low residue diet for 2 days prior to exam • Pt. must be NPO after midnight • AP scout generally obtained prior to exam

36. UGI Positioning - AP Projection • Position • Supine • CR • MSP at L1-L2 • Between MSP and left side if using small film • At MSP if using 14 X 17 • Structures • Barium filled fundic portion • Hiatal hernias, if present

37. Single Contrast Shows size, shape, and position of stomach Examines changing contour of stomach during peristalsis Observe filling and emptying of duodenal bulb Single v. Double Contrast

38. Double Contrast • Mucosal lining is well visualized • Small lesions are less easily obscured

39. Compare Single and Double Contrast

40. Which is taken AP and which is taken PA?

41. UGI Study - PA Projection • Prone Position • Center at MSP if using 14 X 17 • CR • Perpendicular to plane of film at level of L1-L2

42. UGI study - PA Projection • Structures shown? • Size, shape, and relative position of stomach • Evaluation: • All pertinent anatomy • No rotation • Exposure sufficient to penetrate barium • Surrounding structures visible

43. UGI Positioning - PA Oblique Projection • Position • Recumbent • Body rotated 40 - 70 degrees • Hypersthenic patients require more rotation • CR • Perpendicular to L1-L2 • Between vertebral column and elevated lateral border of the abdomen

44. UGI Positioning - PA Oblique Projection • Structures • Entire duodenal loop • Best image of pyloric canal and duodenal bulb • Evaluation • All pertinent anatomy • No superimposition of pylorus and duodenal bulb • Duodenal bulb and loop in profile

45. UGI Positioning - AP Oblique Projection • Position • Supine • Right side elevated 30 - 60 degrees • Average about 45 degrees • CR • Between vertebral column and left lateral border at L1-L2 • Structures • Fundic portion of stomach filled with barium • Evaluation • All pertinent anatomy • No superimposition of pylorus and duodenal bulb • Barium filled fundus

46. Lateral Projection • Position • Lateral recumbent - right side • CR • Level of L1-L2 • Between midcoronal and anterior of abdomen

47. Lateral Projection • Structures • Pyloric canal and duodenal bulb in hypersthenic patients • Evaluation • No rotation • All pertinent anatomy

48. Small Bowel Follow Through • Preparation • Low residue diet for 2 days prior when possible • NPO after midnight before exam • Examination Procedure • Scout film obtained • Patient drinks barium • Images obtained in prone or supine position • Images begin 15 minutes after barium ingested • Barium usually reaches ileocecal valve in about 2 -3 hours

49. Radiography Of Small Intestine • Contrast administration 3 Ways • Orally • Retrograde • Reflux filling via barium enema • Direct injection of contrast through NG tube • Enteroclysis (Radiocontrast is infused through tube inserted through nose to duodenum, and images are taken in real time as contrast moves through)

50. Small Bowel - AP/PA Projection • Patient supine or prone • CR centered to level of L2 for early films • Iliac crest for later films • Continue taking radiographs until barium reaches terminal ileum • Fluoroscopic spot films may be taken of terminal ileum