Abdominal radiology 腹部放射線學

Transcription

1 Abdominal radiology 腹部放射線學 台北醫學大學 - 市立萬芳醫院 留偉順 laowilson@hotmail.com

2 The Normal Abdominal Series Chest Supine abdomen Erect abdomen Left lateral decubitus abdomen

3 Learning objectives Understanding normal plain abdomen radiographs Understanding abnormal plain abdomen - Calcifications - Gas - Masses - Others

4 What to Examine l l l l Gas pattern Extraluminal air Soft tissue masses Calcifications

5 The Check List Bones and joints Calcifications Organs Fat Gas: In and outside of bowel

6 A memory aid First organs, bones, and stones, Then masses, fat, and gas. Don t forget the corner zones, And you ll always cover your subject

7 Abdominal Calcifications l l l Rimlike Linear or track-like walls of tubes such as ureter, arteries Lamellar gallstone, myoma

8 Rimlike Calcification Wall of a hollow viscus Cysts Renal cyst Aneurysms Aortic aneurysm Saccular organs e.g. GB Porcelain Gallbladder

9 AAA

10 AAA: CT

11 Renal Cyst Gallbladder Wall

12 Lamellar or Laminar l Formed in lumen of a hollow viscus n n n Renal stones Gallstones Bladder stones

13 Stone in Ureterocoele

14 Staghorn Calculi

15 Chronic Pancreatitis

16 Normal Gas Pattern Gas in the stomach. Some gas in the small bowel. Gas in the rectum and sigmoid.

17 Gas in stomach Gas in a few loops of small bowel Gas in rectum or sigmoid

18 Abnormal Gas Patterns l l Functional Ileus n n Localized (Sentinel Loops) Generalized adynamic ileus Mechanical Obstruction n n SBO LBO

19 Large vs. Small Bowel l l Large Bowel n n Peripheral Haustral markings don't extend from wall to wall Small Bowel n n Central Valvulae extend across lumen n Maximum diameter of 2"

20 Sentinel Loops Cholecystitis Pancreatitis Ulcer Appendicitis Diverticulitis

21 Air in Rectum or sigmoid Air in Small Bowel Air in Large Bowel Localized Ileus Yes 2-3 distended loops Air in rectum or sigmoid Generalized Ileus Yes Multiple distended loops Yes- Distended SBO No Multiple dilated loops No LBO No None-unless ileocecal valve incompetent Yes- Dilated

22 Small Bowel Obstruction: Causes Adhesions 80% Hernia 15% Tumors, intussusception, midgut volvulus, etc.

23 COLON Obstruction Causes Carcinoma of the colon 80% Volvulus 5% Diverticulitis 5% Fecal impaction 5% Others 5%

24 Small Bowel Obstruction: Findings Step-ladder dilated bowel loops on supine view Step-ladder air-fluid levels on erect/decubitus views String-of-pearls sign on erect/decubitus views

25 Small Bowel Obstruction, Supine

26 Air Filled Small Bowel

27 Supine Prone Sentinel Loops

28 String-of-Pearls Sign: Erect

29 Fluid Filled Small Bowel

30 LBO

31

32 Sigmoid Volulus:

33 Air in Biliary System Usually secondary to surgery on bile ducts Can be due to biliary-bowel fistula from infection or neoplasm Rarely, can be due to infection

34 Air in Gall Bladder

35 Air in Bile Ducts

36

37 PNEUMOPERITONEUM FREE AIR: Perforated Gut

38 Free Air Best views: Erect chest and left lateral decubitus abdomen Erect abdomen is less sensitive Supine abdomen is insensitive

39 Free Air: Left Lateral Decubitus Right side up, left side down Patient who can t sit or stand Air under right abdominal wall

40 Imaging findings Large collection of gas Abdominal distension, no gastric air-fluid level "Football sign" = large pneumoperitoneum outlining entire abdominal cavity "Double wall sign" = "Rigler sign" = air on both sides of bowel as intraluminal gas and free air outside (usually requires >1,000 ml of free intraperitoneal gas + intraperitoneal fluid) "Telltale triangle sign" = triangular air pocket between 3 loops of bowel "Inverted V sign" = outline of both lateral umbilical ligaments (containing inferior epigastric vessels) Outline of medial umbilical ligaments (obliterated umbilical arteries) "Urachus sign" = outline of middle umbilical ligament

41 Free Air: Erect Chest

42 Crescent sign Free Intraperitoneal Air

43 Free Intraperitoneal Air Air on both sides of bowel wall Rigler s Sign

44 Falciform Ligament Sign

45 Air in Lesser Sac

46 lateral umbilicus sign (arrow)

47 urachus sign

48 Falciform ligament sign

49 air in the Morison pouch

50 bowel relief sign (arrow).

51 Extraperitoneal Air

52 Pneumoretroperitoneum From perforation of posterior extraperitoneal portions of duodenum or colon Extension from or through the mediastinum

53 Pneumoretroperitoneum

54 Supine anteroposterior abdominal radiograph shows a calcified appendicolith (white arrows) in the right lower quadrant. The bowel gas pattern is nonspecific, with mildly dilated, air-filled small bowel loops in the right upper quadrant. The left psoas muscle margin (black arrows) is normal and distinct; the right psoas muscle margin is not seen.

55 Soft Tissue Masses l l Hepatosplenomegaly n Plain films poor for judging liver size Tumor or cyst n Bowel displacement

56 Splenomegaly

57 Body Packer

58 Bladder Outlet Obstruction pre- and post- cath

59 Right Renal Cyst

60 Foreign Body: Battery

61 Free Peritoneal Fluid- Bladder Ears

62 Atherosclerosis Calcification Vas Deferens

63 Nephrocalcinosis Myomatous Uterus

64 Supine Erect Generalized Adynamic Ileus

65 Summary Abdominal Series Abdominal Calcifications Normal and Abnormal Gas Patterns Large vs. Small Bowel Soft Tissue Masses