1. The Role of Diagnostic Imaging in Appendicitis
D. Joseph Grunz, MD
Department of Radiology
Mercy Children’s Hospital- St. Louis

2. Objectives
Discuss current topics and role of diagnostic imaging for evaluation of appendicitis
Discuss controversies regarding specific imaging techniques, especially regarding multi-detector computed tomography and ultrasound
Discuss current preferences and imaging strategies

3. CT vs. US Benefits of CT studies Downside of CT studies
Rapid evaluation
High degree of diagnostic confidence
High degree of reproducibility
Evaluation of other etiologies
Decreased negative laparotomy and perforation rates
Downside of CT studies
Radiation concerns
IV contrast usage

4. CT vs. US Benefits of ultrasound Downside of ultrasound
No use of radiation
Evaluation of pelvic disease in girls
Can localize to site of pain
Downside of ultrasound
Not on site after hours
Lower degree of diagnostic confidence
Lower degree of reproducibility
Limited evaluation of other etiologies

5. CT Findings
Normal appendix- blind ending tubular structure with air

6. CT Findings
Dilated tubular fluid structure with contrast-enhancing walls, possible appendicolith

7. US Findings
Normal appendix, compressible, less than 6 mm in thickness

8. US Findings
Abnormal appendix, non-compressible, increased vascular flow, fluid-filled

9. Choosing Wisely
American College of Radiology- Five Things Physicians and Patients Should Question
1. Don’t do imaging for uncomplicated headache.
2. Don’t image for suspected pulmonary embolism (PE) without moderate or high pre-test probability.
3. Avoid admission or preoperative chest x-rays
4. Don’t do computed tomography (CT) for the evaluation of suspected appendicitis in children until after ultrasound has been considered as an option.
5. Don’t recommend follow-up imaging for clinically inconsequential adnexal cysts.

10. ACR-Choosing Wisely
Although CT is accurate in the evaluation of suspected appendicitis in the pediatric population, ultrasound is nearly as good in experienced hands. Since ultrasound will reduce radiation exposure, ultrasound is the preferred initial consideration for imaging examination in children. If the results of the ultrasound exam are equivocal, it may be followed by CT. This approach is cost-effective, reduces potential radiation risks and has excellent accuracy, with reported sensitivity and specificity of 94 percent.

11. The way we were 1981 1988 Computed tomography? It will never last!
R. Brooke Jeffrey- early US advocate
Goal was to reduce unnecessary laparotomy rates
Establish criteria to exclude appendicitis
Take home point- US appendix has been around a long time.

12. Are We Resistant to New Technology?
PACS technology CT angiography
CT perfusion CT urography
CT 3D reformat CT coronary artery
MR enterography MR angiography
MR cholangiogram US pyloric channel
US sonohysterography US musculoskeletal

13. Intussusception
Standard of care was barium enema reduction

14. Intussusception
Air insufflation enema adopted

15. Intussusception
Ultrasound

16. Come and gone Intravenous pyelography Plain film tomography
Herniography
Venography
CT colonoscopy
CT screening for cancer

17. Not yet or never were US gastro-esophageal reflux
US voiding cystourethrography
US malrotation/midgut volvulus
US intussusception reduction
US with IV contrast

18. It’s not over until … CT pulmonary angiogram vs. V/Q scan
Fluoroscopic voiding cystourethrogram vs. nuclear medicine voiding cystourethrogram
CT angiography vs. MR angiography vs. conventional angiography
MR lumbar spine vs. CT lumbar spine myelography

19. “When the facts change, I change my mind. What do you do, sir?”
― John Maynard Keynes

20. 1999-2000 Increased reliance on CT for diagnosis of pediatric appendicitis
95 % sensitivity, 94 % specificity
Alternate diagnosis in 34 %

22. USA Today 2001
Children are exposed to unnecessary radiation doses for CT studies.
Children are receiving adult radiation settings for CT studies
CT studies should be calibrated for child age/size

23. 23

24. New England Journal of Medicine, Nov. 2007
“The largest increases in CT use have been in the categories of pediatric diagnosis and adult screening.”
“There is direct evidence from epidemiologic studies that the organ doses corresponding to a common CT study (two or three scans, resulting in a dose in the range of 30 to 90 mSv) result in an increased risk of cancer. The evidence is reasonably convincing for adults and very convincing for children.”
*Brenner, D. et al. NEJM 357, , Nov. 29, 2007

25. Children are at higher risk to develop cancer because…
Children are more radiosensitive
Children have a longer lifespan for cancer to develop

26. Increased ED utilization 2000-2006

27. Public Awareness (?)

29. 2011 Articles
There has been significantly increased utilization of CT scans in the pediatric emergency room setting.
Based upon population studies, if 1.6 million CT studies are performed, there is a theoretical risk that 1,500 children will develop a fatal neoplasm as a result
Did not conclude these exams were unnecessary, but such was the implication

30. Back to Ultrasound Stats

31. Sweden (2002) Children US sensitivity 86%, specificity 95%
CT sensitivity 80%, specificity 97%
Prevalence of 41%
Negative predictive value of 92%

32. High sensitivity study- Kessler, France (2004)
125 patients, appendicitis prevalence of 46%
Appendix identified in 86% of patients
Appendix identified in 96% of patients with appendicitis
Appendix identified in 72% of patients without appendicitis
Negative predictive value of 90% if appendix not visualized

33. Meta-analysis study (2006)
US sensitivity 88%, specificity 94% for children
CT sensitivity 94%, specificity 95% for children

34. Our experience Matches CT experience of other institutions
Nowhere close to the ultrasound percentages for finding the appendix, making the diagnosis, or excluding the diagnosis

35. "When you unwrap a Reggie bar, it tells you how good it is
"When you unwrap a Reggie bar, it tells you how good it is." - Catfish Hunter

36. University of Michigan, Pediatric Radiology, March 2012
Observed their experience doesn’t correspond as well as described in the literature
Identified the appendix 24% of the time.

40. What to do?

41. Understand the Issues for the ED physicians

42. ED Issues
Safe, reliable, available diagnostic exam for appendicitis is highly desirable
Discharge home or admission for observation is frequently undesirable
Unstable social situation
Long travel distance
Rapid clinical deterioration
Pain control
Limited hospital beds
Malpractice issues

43. Risks of Appendicitis
Most common acute abdominal condition requiring childhood surgery
Commonly missed or delayed diagnosis
Complications include peritonitis, sepsis, bowel obstruction, death
Second most common cause for litigation, and one third of claims involve diagnostic error

44. Put risks into perspective
Lifetime cancer risk is 44.00% for men, 38.00% for women
Single CT scan for a child age five theoretically increases that risk 00.02%
Physicians need to understand the risk/benefit
Risk of missed diagnosis is immediate and real
Risk of radiation exposure is delayed and theoretical
Eliminate unnecessary exams, not necessary exams

45. Estimated Lifetime Risk of Death
Lightning strike
Bicycle accident
Drowning
Motor vehicle accident
Cancer (natural causes)
Cancer, pediatric (single CT)
1 in 100,000
1 in 10,000
1 in 1,000
1 in 100
1 in 3-4
1 in ,000

46. Understand institutional/population bias
Patient population
Prevalence of obesity
Relevant for US vs. CT
Social/cultural conditions
Time of presentation/need for follow-up
Age/gender of patients
Younger children/adolescent females
Institution resources/support

47. My biases
Awareness of cancer risks associated with pediatric CT need to be raised
Alternatives to CT studies need to be explored
If there is a low pre-test probability, neither ultrasound nor CT study is an appropriate diagnostic imaging examination
If there is mid to high pre-test probability, and it will likely change the course of treatment, CT is the study of choice for appendicitis

48. Pre-test probability

49. My bias against ultrasound
There is still controversy about this exam, decades after introduction, even among highly qualified radiologists
The appendix is not found in ¾ of all examinations
When the appendix is not found, appendicitis can’t be excluded
When the appendix is found and appendicitis suspected, there is still a false positive rate of 25%
The immediate risk of patient harm from missed ultrasound diagnosis is much more compelling than the theoretical risk (and lower) long-term risk from medical radiation

50. My bias in favor of CT studies
If the appendix is seen and normal, no appendicitis
If the appendix is not seen, but no other abnormalities identified, very low chance of appendicitis
If the appendix is inflamed, then surgery
If the appendix is not seen but inflammation present, follow closely

51. Trends for the future Better physician and patient education
Clinical decision rules to minimize need for imaging
Awareness of the issues and time constraints upon ED physicians for rapid diagnosis
Development of alternatives to CT studies
Technical alteration of CT protocols to minimize radiation exposure

52. Conclusions

53. Conclusions
There is still controversy concerning diagnostic imaging for appendicitis in pediatric patients
We are pro-active in keeping medical radiation exposure as low as reasonable achievable
The experience with our pediatric population, emergency room physician expectations for accuracy, and surgical follow-up has led us to recommend CT studies for appendicitis in the appropriate clinical setting