1. Introduction to Abdominal Radiology
Meghan Woodland, DVM

2. Indications Vomiting/Diarrhea Abdominal Pain Hematuria
Abdominal Mass/Distension
Tenesmus (Pain on Defecation)

3. Technical Factors Abdomen has low inherent contrast Collimation
Lower kVp
Higher mAs
Collimation
High amount of scatter
Use grid (if patient is >10-11cm thick)
Take exposure on expiration
Multiple soft-tissue opacity structures surrounded by variable amounts of fat = low inherent contrast.
Don’t want mAs too high because of diaphragm motion during respiration
Use a grid when the patient is >10-11cm thick.
No compression of abdominal organs when expiration.

4. Positioning VD and R lateral views
Include from diaphragm to pelvic inlet
Fore limbs pulled cranially
Hind limbs pulled caudally
Additional views as necessary
Horizontal beam VD view = free abdominal gas. (L lateral recumbency)
Obliques = renal contrast studies
Butt shot = legs pulled forward, to evaluate for urethral calculi
Large dogs = two films may be necessary. Ensure overlap of structures.

5. Sandbags, positioning aids.
Radiographic techniques: the dog
 By Joe P. Morgan, John Doval, Valerie Samii

6. Radiographic techniques: the dog
 By Joe P. Morgan, John Doval, Valerie Samii

8. Improper positioning. Could miss a diaphragmatic hernia.
Example of improper positioning. Should include entire diaphragm – could miss a diaphragmatic hernia in this case.

9. Unprepared abdomen – Owner can withhold food for hours or can promote defecation (walking, enemas)
Unprepared Abdomen

10. “Butt Shot” – Urethral Calculi

11. Interpretation of Abdominal Radiographs
Liver
Spleen
Kidneys
GIT (Stomach, SI, Cecum, LI)
Bladder
Prostate
Extra-abdominal structures
Structures normally seen

12. Structures Not Normally Seen
Gall bladder
Pancreas
Adrenals
Ovaries
Uterus
Ureters
Lymph Nodes
Mesentery
Vasculature

13. Liver Lateral view: VD view: Caudo-ventral margin angular
Should not extend beyond the costal arch
Normal gastric axis parallel to ribs or perpendicular to spine
VD view:
Liver margins not well seen
Long axis of stomach perpendicular to spine
Normal gastric axis = a line drawn dorsal to ventral through the stomach in the lateral view)

15. Over-inflation of chest gives false appearance of enlarged liver
Hyperinflation of chest – false appearance of liver enlargement

17. Spleen Size is subjective Lateral view: VD view:
Tail of spleen visible, but position varies
Not usually seen on this view in cats
VD view:
Head of the spleen is visualized
Caudo-lateral to stomach fundus
Cranio-lateral to left kidney
Cats : often seen lying along the left body wall
No set size parameters

18. Dog – Lateral View

19. Dog – VD View

20. Cat – Lateral View

21. Cat – VD View

22. Kidneys Right located cranial to left
May be difficult to see in young or emaciated animals
Size (only evaluated on VD view)
Dogs: 2 ½ to 3 ½ times the length of L2
Cats: 2 to 3 times the length of L2
Lateral view = kidneys may be magnified
2.4-3

23. Right = renal fossa of the liver
Dog – Lateral View

24. Dog – VD View
Difficult to always visualize both kidneys.

25. Cat – Lateral View

26. Cat – VD View

27. Gastrointestinal Tract
Stomach
Caudal to liver
Gastric Axis
Less than 3 ICS wide on lateral view
VD:
Dog = U-shaped
Cat = J-shaped
U-shaped = crosses midline. Fundus is left and pylorus is right
J-shaped = Left cranial abdomen, does not cross midline

28. Gastric Axis

29. “U-Shaped” Stomach
Dog
Dog – VD View

30. “J-Shaped” Stomach
Cat
Cat – VD View

31. Gastrointestinal Tract
Small Intestine
Size: Width less than 3 times the last rib
Duodenum
Fixed along the right side
Extends caudally from the pyloric region of the stomach
Jejunum/Ileum
Position Varies
Mid-ventral abdomen
Small Intestine contains both air and fluid (Dogs have more gas than cats).
Terminal ileum = L1-L3 in mid or dorsal abdomen

33. Gastrointestinal Tract
Cecum
Comma shaped
Mid, right abdomen
Not often seen in cats
Large Intestine
Ascending, transverse and descending colon
Size: Width less than 5 times the last rib
Dogs – cecum is ventral to L3 on lateral and to the right of midline on the VD. Cats – rarely contains gas therefore not visualized routinely.
Ascending colon = extends cranially from the cecum to the right of midline.
Transverse colon = crosses to the left of midline at approx. L1.
Descending colon = Extends caudally to the left of midline until the pelvic inlet.

34. Cecum – VD View

35. Cecum – Lateral View

36. Megacolon in a Dog
Descending colon
Transverse Colon
Ascending Colon

37. Transverse Colon
Ascending Colon
Descending colon
Contrast Study

38. Bladder Size varies Dog: Cat: Oval to ellipsoid
Caudal abdomen or pelvic
Cat:
Ellipsoid
Always intra-abdominal (elongated bladder neck)

39. Bladder more pelvic
Dog – Lateral View

40. Long Bladder Neck
Cat – Lateral View

41. Prostate Intact males ++ Caudal to bladder
Symmetrical with smooth margins
Size:
Lateral: Less than 70% of sacro-pubic distance
VD: Less than 50% of pelvic inlet width
Larger in intact or older male dogs.
Not visualized in male cats.

43. Extra-Abdominal Structures
Soft Tissues
Bone (Spine, Pelvis, Hind limbs)
Diaphragm
Thorax (if visible)

45. Decreased Abdominal Detail
Inability to distinguish organs
Causes:
Young Animals *
Emaciated Animals
Peritoneal Fluid
Inflammation (Peritonitis, Pancreatitis)
Carcinomatosis
 Normal finding
Contrast is due to fat, therefore decreased fat = decreased contrast
Young animals = puppies and kittens less than 6-8 months of age

46. Emaciated Cat

47. Abdominal Fluid

48. Fun Slides
How Many Babies?

49. Where is the foreign body?

50. What organs are mineralized?

51. ????

52. 1

53. 2

54. THE END!