1. Ultrasonography: Where to start?
Tony Pease, DVM, MS
Assistant Professor of Radiology
North Carolina State University

2. Chapter 4 in Nyland/Mattoon
Reading
Chapter 4 in Nyland/Mattoon or
Chapter 2 in Thrall

3. RELAX!

4. Objectives
Machine
Terminology
Examination

5. Examination
Image orients like a radiograph

6. Ultrasound Pitfalls Technical demand on time and patience
Non-specific change
Tissue characterization yet to be realized
Opening Pandora’s Box
Multiple abnormalities but you may not known the clinical importance

7. Fatal assumptions Speed of sound is an average
1540 m/sec
All sound waves are assumed to be created by a primary beam

8. Ultrasound Knobs

9. Power vs. Gain Power = preprocessing Gain = post-processing
Controls energy given to the transducer to regulate intensity of the sound wave
Gain = post-processing
Increases the overall brightness given to the returning signal

10. Power Gain

11. Time Gain Compensation
Also called TGC
Will adjust gain at different depths
Helps make the image uniform

12. Time Gain Compensation

13. Beam and focal spots
Nyland, Small Animal Diagnostic Ultrasound

14. Focal Spot

15. Tissue Harmonics Ultrasound wave goes in
5 MHZ
Transducer listens for a higher frequency
10 MHz
This is generated by the tissue imaged

16. Harmonics Benefit Only goes through tissue once
Less artifacts
Penetrates better than 10 MHz
But not as good as a 5 MHz wave

17. Without With
Harmonics Harmonics

18. Types of probes
Linear array
Curvilinear
Phased array

19. How does it work?
Nyland, Small Animal Diagnostic Ultrasound

20. What about MHz? Generally 1-13 MHz Multiple frequencies in one probe
Higher number = better resolution
Decreased penetration

21. Bottom line For canine abdomen For feline abdomen Average size dog
Use a 5-8 MHz probe
Deep-chested dog
Use a 3-5 MHz probe
For feline abdomen
Can use MHz probe

22. Terms
Hyperechoic
Hypoechoic
Isoechoic
Anechoic

23. Hypoechoic to hyperechoic
1. Bile, urine
2. Muscle
3. Renal medulla
4. Renal cortex
5. Liver
6. Fat
7. Spleen
8. Prostate
9. Renal sinus
10. Vessel walls
11. Bone, gas

24. Everything’s relative
Echogenicity is a comparison

25. Examination
Abdomen
No set protocol
Thorax
Echocardiograph
Lateral

26. Abdominal Ultrasound Patient preparation
Clip or alcohol
Acoustic coupling gel
Appropriate probe selection (MHz)
Image optimization takes time
May need to switch transducers or change frequencies

27. Abdomen Dorsal recumbency Lateral recumbency Clockwise exam
Organ approach

28. Ultimate goal
Examine all organ systems
Examine in a routine fashion

29. Liver/Gallbladder

30. Liver

31. Where we are

32. Stomach (dog)

33. Stomach (cat)

34. Left limb of pancreas

35. Spleen

36. Left kidney

37. Adrenal gland

38. Variability of adrenal glands

39. Canine left adrenal gland

40. Feline left adrenal gland

41. Aorta

42. Aorta

43. Urinary Bladder

44. Medial iliac lymph node

45. Right kidney

46. Right adrenal gland - Dog

47. Right adrenal gland - Cat

48. Right limb of pancreas

49. Mesenteric lymph nodes

50. Small intestine and colon

51. Intestinal layering Superficial to deep Serosal = White
Muscularis = Black
Submucosal = White
Mucosal (thickest) = Black
Mucosal-luminal interface = White

52. Uterus

53. Pregnancy Can see heart beat around 21 days
Can see limb buds by 32 days
Check for viability

54. Other uses Brain imaging Laryngeal exam Guided aspirates
Contrast studies
Thyroid gland
Ocular exam
Blood flow
Umbilicus

56. Ultrasound guided techniques
Needle approximate 45 degree angle
Use appropriate needle length for target
Be mindful of surrounding vessels

57. Cystocentesis

58. Fine needle aspirate