1. SONOGRAPHY OF THE APPENDIX
Harry H. Holdorf PhD, MPA, RDMS (Ab, Ob, BR), RVT, LRT(AS)

2. Understand the main drivers promoting sonography of the appendix
objectives
Understand the main drivers promoting sonography of the appendix
Provide a better understanding of the anatomy of the appendix and how appendicitis occurs
Assist the sonographer in developing a protocol or “plan of attack”

3. BACKGROUND
Each year, in the United States 250,000 cases of appendicitis are reported, representing 1 million patient-days
Considering appendectomy carries a 4-15% complication rate, there are increased costs as well as increased hospital stays
In order to minimize the risk of complications, the surgeon must make an accurate diagnosis as soon as possible
The mortality rate for acute appendicitis is currently %
The mortality rate for children is between 0.1-1%
The mortality rate for adults older than 70 is above 20%

4. LEGAL RISK
In children less than 3 years old, the rate of appendiceal perforation is %
In children 10 to 17 years old, the rate of appendiceal perforation is less than 10-20%
Delay in diagnosis increases the perforation rate
Increase in perforation rate will increase the mortality and morbidity rate
A quick and accurate diagnosis is invaluable information for the surgeon

5. LEGAL RISK
The overall complication rate of appendectomy depends on the status of the appendix at the time that the appendix is removed
If the appendix is not ruptured, the overall complication rate is only about 3%
If the appendix has ruptured, the complication rises to almost 59%

6. MONETARY RISK
Timely diagnosis reduces the complication rate, thereby reducing:
Costs associated with complications
Costs associated with longer hospital stays
If diagnosis can be made with sonography instead of CT, there are huge global healthcare cost savings

7. MONETARY RISK
Today we find ourselves in an environment of healthcare reform. Although we do not know all the specifics yet, we do know that the cost of diagnosing any disease process has become very important
With sonography, we find ourselves in a very advantageous position
Due to our relatively low cost and because there are no adverse side effects, sonography will increasingly become the modality of choice

8. RADIATION RISK
It has been estimated that approximately 62 million CT scans are performed per year, including at least 4 million per year for children
The growth of CT use in children has been primarily due to the decrease in time it takes to perform a scan, now less than 1 second.
The major growth area, in children, has been presurgical evaluation of appendicitis

9. RADIATION RISK
Most of the quantitative data that we have regarding radiation-induced cancer comes from survivors of the Atomic bombs dropped in Japan in 1945
The mean dose of radiation was about 40 mSv, which is approximately equal to a typical CT involving two or three scans in an adult.
Children are at greater risk than adults due to these two facts:
They are much more radiosensitive than adults
They have more remaining years of life in order to potentially develop a radiation-induced cancer

10. ANATOMY Vermiform appendix comes from Latin and means “worm-shaped”
Blind-ended tube at the end of the cecum
Average length is 10cm and measures between 3-6mm in diameter

11. ANATOMY Layers of the appendix Mucosal lining with a collapsed lumen
Submucosa
Muscular wall
Serosa

12. Although the neck of appendix is fairly consistent, approximately 2
Although the neck of appendix is fairly consistent, approximately 2.0cm below the cecal valve, the tip location can be variable.
It could be introperitoneal 95% of the time,
it could be retroperitoneal 5% of the time,
it could be behind the cecum 65% of the time,
and it could also be in the pelvis approximately 30% of the time.

13. LOCATION IS VARIABLE Intraperitoneal 95% Retroperitoneal 5%
Behind the Cecum 65%
In the pelvis 30%

14. Location
McBurney’s point is the name given to the point over the right side of the abdomen that is approximately one-third of the way between the anterior superior iliac spine and the umbilicus. This point is roughly the location of the base of the appendix where it is attached to the cecum.

15. LOCATION
McBurney’s Point

16. Although the base of the appendix is usually around McBurney’s point,
the tip can be anywhere in the right lower quadrant.

17. LOCATION

18. CAUSES OF APPENDICITIS
Appendicitis results from obstruction of the lumen of the appendix
Obstruction may be caused from:
Lymphoid hyperplasia 60%
Fecalith or fecal stasis 35%
Foreign body 4%
Tumor 1%

19. Lymphoid Hyperplasia
Only a few submucosal lymphoid follicles are noted at birth
These follicles enlarge, peaking between years old
These same follicles decrease in size after peaking at age 12-20
This correlates well with the incidence of appendicitis
This form of obstruction is mostly observed in children and is known as catarrhal appendicitis

20. Progression
Following obstruction, there is an increase in the production of mucous which leads to an increase in pressure
Following increased pressure and stasis from obstruction, there is an overgrowth of bacteria
Mucous then turns into pus which increases the luminal pressure even more
This leads to distension of the appendix and visceral pain which is usually located in the epigastric or periumbilical area
As the luminal pressure increases, obstruction of the lymphatic system occurs causing edema of the appendix

21. Progression This stage is called acute or focal appendicitis
The overlying parietal peritoneum becomes irritated, and the pain now becomes localized to the RLQ
This progression is the classic migration of pain that is often seen in patients with appendicitis

22. CAUSES OF APPENDICITIS
Lymphoid hyperplasia predominately occurs within the mucosal and submucosal areas
Mucosa
Submucosa

23. CAUSES OF APPENDICITIS you can typically see these areas becoming more prominent and darker on sonography
Lymphoid hyperplasia predominately occurs within the mucosal and submucosal areas
Mucosa
Submucosa

24. CAUSES OF APPENDICITIS
The serosal surface may also become thicker and more hypoechoic
Mucosa
Submucosa

25. Normal appendix Inflamed appendix
Two images of the appendix. Note that in the inflamed appendix the mucosal and sub mucosal layers are thickened .

26. CLINICAL PRESENTATION
Patient experiences anorexia, and then vague periumbilical pain
Over the next several hours pain usually migrates to Right Lower Quadrant
Nausea and Vomiting, if present, will follow the pain
Diarrhea may occur
Fever, if present, is low grade
Appendix commonly ruptures hours after onset of symptoms

27. REALITY
When a Technologist mentions to the physician that we should be evaluating the appendix with sonography instead of CT, this is the look that they usually get…

29. Physicians and technologists: Overcome your fear!!
“I can never find the appendix”
“If I can’t find it, they always do a CT”
“Just tell them to do a CT instead, and that will just save a step”
You have to be willing to accept the challenge and try to find the appendix
With newer equipment and newer transducer technology, it is becoming a lot easier to image the appendix

30. Overcome your fear
If you are willing to accept the challenge and begin the process of improving your proficiency in finding the appendix with sonography, you can:
Help reduce radiation exposure, especially in the pediatric population
Become more proficient and begin to separate yourself and/or your practice from your peers

31. Be persistent
After failing to find the appendix in your first several attempts, it becomes easy to just quit trying
Becoming proficient in sonography of the appendix is a process and you shouldn’t be discouraged
Don’t fall into the trap of taking just a couple of images of the Right Lower Quadrant (RLQ) to show that you at least looked

32. Be persistent
It’s easy to say that “if it’s positive and I’m going to find it, I should find it right away”
Sonography of the appendix is not only about finding a case of appendicitis, but also about trying to find a normal appendix
At times, it can take at least 10 to 15 minutes of careful scanning just to find a portion of the appendix
If you are able to find the entire length of the appendix and it’s normal, you have statistically ruled-out appendicitis and changed the course of medical management for that patient.

33. Be organized
Use a high-frequency, linear transducer (10 MHz or higher). A lower frequency may be needed for large patients.
Start with graded compression over the area of maximum tenderness, as determined by the patient.
If the appendix is not identified in that location, a careful, systemic approach should be initiated.
Begin by placing the transducer in a transverse position and apply deep graded compression, which will help to displace the gas and bring the bowel closer to the transducer.

34. Be organized
Begin at the hepatic flexure and slowly move down toward the cecum
Continue in a slow, methodical fashion making sure that the whole RLQ area is evaluated until, hopefully, the appendix is identified
The appendix is not always identifiable due to bowel gas or body habitus

35. Be organized
Make sure that you also look for secondary signs of a possible appendicitis which could include:
Free fluid in the right lower quadrant
Changes with echogenic inflammatory periappendiceal fat
Enlarged mesenteric lymph nodes
Presence of positive rebound tenderness

36. Be organized This is a suggested addition to your protocol:
If you find the appendix and it is positive for appendicitis, you are done
If you find the appendix and it is normal, or if you can’t find the appendix
Take a quick look at the right kidney to make sure there is no hydronephrosis and normal flow from the right ureter. This may save the patient from having a CT trying to diagnosis a possible appendicitis, just to diagnosis a right ureteral stone
If the patient is a female, take a quick look at the right ovary to make sure that the ovary is not the cause for the pain

37. Be CAREFUL This is a case of a 3 year old girl where sonography was not able to see the appendix, but also missed and area of very abnormal echogenic fat. This area was seen in retrospect, the next day. Because this area was not noticed during the exam, a CT was ordered, which then diagnosed appendicitis.

38. Be CAREFUL

39. Be CAREFUL
Mesenteric adenitis can also mimic appendicitis .

40. Be CAREFUL
The presence of an appendicolith may be present in the normal or abnormal appendix. If one is seen in a normal appendix in a pediatric patient, make sure that it is noted as this patient may be a candidate for elective appendectomy. This is not necessarily so in the adult patient.

41. Be CAREFUL
Appendicolith

42. Be CAREFUL Make sure that if you see air outside of the appendix you will always mention it, as this is a possible sign of appendiceal perforation.

43. Be CAREFUL
A ruptured or perforated appendix can measure with a normal diameter
Notice the surrounding fluid with internal echoes

44. I wish they were all this easy!

45. I wish they were all this easy!

46. NORMAL APPENDIX Will measure 6mm or less in AP diameter
Must be blind-ending
Will be partially compressible
Will not have any peristalsis
Be careful not to push too hard as this may limit peristalsis

47. MEASURE CORRECTLY
Because a normal appendix is not usually perfectly round, make sure that you measure AP (anterior posterior) and not transversely
Wrong
Correct

48. The following slides contain images of normal appendices

49. NORMAL APPENDIX measuring 5.2mm

50. NORMAL APPENDIX

51. NORMAL APPENDIX

52. NORMAL APPENDIX

53. NORMAL APPENDIX measuring 2.9mm
This is a transverse image of a normal appendix measuring 2.9mm.

54. NORMAL APPENDIX measuring 3
NORMAL APPENDIX measuring 3.0mm that is seen just posterior to normal peristalsing small bowel

55. NORMAL APPENDIX

56. NORMAL APPENDIX

57. NORMAL APPENDIX

58. NORMAL APPENDIX

59. NORMAL APPENDIX

60. NORMAL APPENDIX

61. A mildly prominent appendix that was interpreted as normal at 5.9mm.

62. NORMAL APPENDIX

63. NORMAL APPENDIX Arrow= Rt ovary

64. NORMAL APPENDIX

65. NORMAL APPENDIX

66. NORMAL APPENDIX

67. NORMAL APPENDIX

68. NORMAL APPENDIX

69. The following slides contain images of abnormal appendices

70. ABNORMAL APPENDIX with an Appendicolith

71. ABNORMAL APPENDIX Mild or early stage of Appendicitis

72. ABNORMAL APPENDIX

73. ABNORMAL APPENDIX

74. ABNORMAL APPENDIX

75. ABNORMAL APPENDIX

76. ABNORMAL APPENDIX

77. ABNORMAL APPENDIX

78. ABNORMAL APPENDIX Perforated-why the lumen appears to be compressed

79. ABNORMAL APPENDIX

80. ABNORMAL APPENDIX with the presence of hyperemia

81. ABNORMAL APPENDIX

82. ABNORMAL APPENDIX-inflammation with swollen adjacent fat

83. MAKE SURE THAT YOU EVALUATE THE ENTIRE APPENDIX
Appendicitis can be confined to only one segment of the appendix
This occurs in approximately 20% of all patients
Can be in either the proximal or distal end
More common in the distal end
If you find a normal segment of the appendix and stop your evaluation there, you may miss a focal appendicitis

84. Next Slide
The appendix in this patient was tortuous and was able to image a normal section of the appendix as well as an inflamed section.
The first section of the appendix appears totally normal.
The second portion of the appendix appears to be inflamed.

86. SUMMARY We have learned:
Some of the main drivers promoting sonography of the appendix, such as
Legal Risks that require a quick, accurate diagnosis for the physician or surgeon
Monetary, or financial Risks showing that sonography has a definite advantage over other modalities, such as CT
Radiation Risks showing that there are serious radiation concerns, particularly for the pediatric population

87. SUMMARY
The anatomy of the appendix, causes of appendicitis and the typical progression of appendicitis
What a normal and abnormal appendix looks like with sonography
There are a few potential pitfalls that we need to keep in mind
We need to overcome our fear, be persistent and be organized in our examination of the appendix
Finally, we have learned a suggested protocol in performing sonography of the appendix

88. The End
Thank you for your time and attention. We hope you have enjoyed this presentation Ultrasound of the Appendix.