The Role of The Role of Diagnostic Imaging Diagnostic Imaging

in Appendicitisin Appendicitis

D. Joseph Grunz, MDD. Joseph Grunz, MD

Department of RadiologyDepartment of Radiology

Mercy Children’s Hospital- Mercy Children’s Hospital- St. LouisSt. Louis

ObjectivesObjectives

Discuss current topics and role of Discuss current topics and role of diagnostic imaging for evaluation of diagnostic imaging for evaluation of appendicitisappendicitis

Discuss controversies regarding Discuss controversies regarding specific imaging techniques, specific imaging techniques, especially regarding multi-detector especially regarding multi-detector computed tomography and ultrasoundcomputed tomography and ultrasound

Discuss current preferences and Discuss current preferences and imaging strategiesimaging strategies

CT vs. USCT vs. US

Benefits of CT studiesBenefits of CT studies Rapid evaluationRapid evaluation High degree of diagnostic confidenceHigh degree of diagnostic confidence High degree of reproducibilityHigh degree of reproducibility Evaluation of other etiologiesEvaluation of other etiologies Decreased negative laparotomy and Decreased negative laparotomy and

perforation ratesperforation rates Downside of CT studiesDownside of CT studies

Radiation concernsRadiation concerns IV contrast usageIV contrast usage

CT vs. USCT vs. US

Benefits of ultrasoundBenefits of ultrasound No use of radiationNo use of radiation Evaluation of pelvic disease in girlsEvaluation of pelvic disease in girls Can localize to site of painCan localize to site of pain

Downside of ultrasoundDownside of ultrasound Not on site after hoursNot on site after hours Lower degree of diagnostic confidenceLower degree of diagnostic confidence Lower degree of reproducibilityLower degree of reproducibility Limited evaluation of other etiologiesLimited evaluation of other etiologies

CT FindingsCT Findings

Normal appendix- blind ending Normal appendix- blind ending tubular structure with airtubular structure with air

CT FindingsCT Findings

Dilated tubular fluid structure with Dilated tubular fluid structure with contrast-enhancing walls, possible contrast-enhancing walls, possible appendicolithappendicolith

US FindingsUS Findings

Normal appendix, compressible, less Normal appendix, compressible, less than 6 mm in thicknessthan 6 mm in thickness

US FindingsUS Findings

Abnormal appendix, non-Abnormal appendix, non-compressible, increased vascular compressible, increased vascular flow, fluid-filledflow, fluid-filled

Choosing WiselyChoosing Wisely American College of Radiology- Five Things American College of Radiology- Five Things

Physicians and Patients Should QuestionPhysicians and Patients Should Question 1. Don’t do imaging for uncomplicated headache.1. Don’t do imaging for uncomplicated headache. 2. Don’t image for suspected pulmonary embolism 2. Don’t image for suspected pulmonary embolism

(PE) without moderate or high pre-test probability.(PE) without moderate or high pre-test probability. 3. Avoid admission or preoperative chest x-rays3. 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 5. Don’t recommend follow-up imaging for clinically inconsequential adnexal cysts. clinically inconsequential adnexal cysts.

ACR-Choosing WiselyACR-Choosing Wisely

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

The way we wereThe way we were

19811981 Computed tomography? It will never Computed tomography? It will never

last!last! 19881988

R. Brooke Jeffrey- early US advocateR. Brooke Jeffrey- early US advocate Goal was to reduce unnecessary laparotomy Goal was to reduce unnecessary laparotomy

ratesrates Establish criteria to exclude appendicitisEstablish criteria to exclude appendicitis Take home point- US appendix has been Take home point- US appendix has been

around a long time.around a long time.

Are We Resistant to New Are We Resistant to New Technology?Technology?

PACS technology CT angiographyPACS technology CT angiography CT perfusion CT urographyCT perfusion CT urography CT 3D reformat CT coronary arteryCT 3D reformat CT coronary artery MR enterography MR angiographyMR enterography MR angiography MR cholangiogram US pyloric channelMR cholangiogram US pyloric channel US sonohysterography US musculoskeletalUS sonohysterography US musculoskeletal

IntussusceptionIntussusception

Standard of care was barium enema Standard of care was barium enema reductionreduction

IntussusceptionIntussusception

Air insufflation enema adoptedAir insufflation enema adopted

IntussusceptionIntussusception

UltrasoundUltrasound

Come and goneCome and gone

Intravenous pyelographyIntravenous pyelographyPlain film tomographyPlain film tomographyHerniographyHerniographyVenographyVenographyCT colonoscopyCT colonoscopyCT screening for cancerCT screening for cancer

Not yet or never wereNot yet or never were

US gastro-esophageal refluxUS gastro-esophageal reflux US voiding cystourethrographyUS voiding cystourethrography US malrotation/midgut volvulusUS malrotation/midgut volvulus US intussusception reductionUS intussusception reduction US with IV contrastUS with IV contrast

It’s not over until …It’s not over until …

CT pulmonary angiogram vs. V/Q scanCT pulmonary angiogram vs. V/Q scan Fluoroscopic voiding Fluoroscopic voiding

cystourethrogram vs. nuclear cystourethrogram vs. nuclear medicine voiding cystourethrogrammedicine voiding cystourethrogram

CT angiography vs. MR angiography CT angiography vs. MR angiography vs. conventional angiographyvs. conventional angiography

MR lumbar spine vs. CT lumbar spine MR lumbar spine vs. CT lumbar spine myelographymyelography

““When the facts change, I change When the facts change, I change my mind. What do you do, sir?”my mind. What do you do, sir?”

― ― John Maynard KeynesJohn Maynard Keynes

1999-2000 Increased reliance on CT 1999-2000 Increased reliance on CT for diagnosis of pediatric for diagnosis of pediatric appendicitisappendicitis

95 % sensitivity, 94 % specificity95 % sensitivity, 94 % specificity Alternate diagnosis in 34 %Alternate diagnosis in 34 %

USA Today 2001USA Today 2001

Children are exposed to unnecessary Children are exposed to unnecessary radiation doses for CT studies.radiation doses for CT studies.

Children are receiving adult Children are receiving adult radiation settings for CT studiesradiation settings for CT studies

CT studies should be calibrated for CT studies should be calibrated for child age/sizechild age/size

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.”

Children are at higher Children are at higher risk to develop cancer risk to develop cancer

because…because… Children are more radiosensitiveChildren are more radiosensitive Children have a longer lifespan for Children have a longer lifespan for

cancer to developcancer to develop

Increased ED utilization Increased ED utilization 2000-20062000-2006

Public Awareness (?)

2011 Articles2011 Articles

There has been significantly increased There has been significantly increased utilization of CT scans in the pediatric utilization of CT scans in the pediatric emergency room setting.emergency room setting.

Based upon population studies, if 1.6 Based upon population studies, if 1.6 million CT studies are performed, there million CT studies are performed, there is a theoretical risk that 1,500 children is a theoretical risk that 1,500 children will develop a fatal neoplasm as a resultwill develop a fatal neoplasm as a result

Did Did notnot conclude these exams were conclude these exams were unnecessary, but such was the unnecessary, but such was the implicationimplication

Back to Ultrasound StatsBack to Ultrasound Stats

Sweden (2002) ChildrenSweden (2002) Children

US sensitivity 86%, specificity 95%US sensitivity 86%, specificity 95% CT sensitivity 80%, specificity 97%CT sensitivity 80%, specificity 97% Prevalence of 41%Prevalence of 41% Negative predictive value of 92%Negative predictive value of 92%

High sensitivity study- High sensitivity study- Kessler, France (2004)Kessler, France (2004)

125 patients, appendicitis prevalence of 125 patients, appendicitis prevalence of 46% 46%

Appendix identified in 86% of patientsAppendix identified in 86% of patients Appendix identified in 96% of patients Appendix identified in 96% of patients

with appendicitiswith appendicitis Appendix identified in 72% of patients Appendix identified in 72% of patients

without appendicitiswithout appendicitis Negative predictive value of 90% if Negative predictive value of 90% if

appendix not visualizedappendix not visualized

Meta-analysis study Meta-analysis study (2006)(2006)

US sensitivity 88%, specificity 94% US sensitivity 88%, specificity 94% for childrenfor children

CT sensitivity 94%, specificity 95% CT sensitivity 94%, specificity 95% for childrenfor children

Our experienceOur experience

Matches CT experience of other institutionsMatches CT experience of other institutionsNowhere close to the ultrasound percentages for Nowhere close to the ultrasound percentages for finding the appendix, making the diagnosis, or finding the appendix, making the diagnosis, or excluding the diagnosisexcluding the diagnosis

"When you unwrap a Reggie "When you unwrap a Reggie bar, it tells you how good it is." bar, it tells you how good it is."

- Catfish Hunter- Catfish Hunter

University of Michigan, Pediatric Radiology,

March 2012

Observed their experience doesn’t correspond as well as described in the literatureIdentified the appendix 24% of the time.

What to do?What to do?

Understand the Issues Understand the Issues for the ED physiciansfor the ED physicians

ED IssuesED Issues Safe, reliable, available diagnostic exam for Safe, reliable, available diagnostic exam for

appendicitis is highly desirableappendicitis is highly desirable Discharge home or admission for observation is Discharge home or admission for observation is

frequently undesirablefrequently undesirable Unstable social situationUnstable social situation Long travel distanceLong travel distance Rapid clinical deteriorationRapid clinical deterioration Pain controlPain control Limited hospital bedsLimited hospital beds

Malpractice issuesMalpractice issues

Risks of AppendicitisRisks of Appendicitis

Most common acute abdominal Most common acute abdominal condition requiring childhood surgerycondition requiring childhood surgery

Commonly missed or delayed diagnosisCommonly missed or delayed diagnosis Complications include peritonitis, Complications include peritonitis,

sepsis, bowel obstruction, deathsepsis, bowel obstruction, death Second most common cause for Second most common cause for

litigation, and one third of claims litigation, and one third of claims involve diagnostic errorinvolve diagnostic error

Put risks into perspectivePut risks into perspective

Lifetime cancer risk is 44.00% for men, Lifetime cancer risk is 44.00% for men, 38.00% for women38.00% for women

Single CT scan for a child age five Single CT scan for a child age five theoretically increases that risk 00.02%theoretically increases that risk 00.02%

Physicians need to understand the Physicians need to understand the risk/benefitrisk/benefit Risk of missed diagnosis is immediate and realRisk of missed diagnosis is immediate and real Risk of radiation exposure is delayed and Risk of radiation exposure is delayed and

theoreticaltheoretical Eliminate unnecessary exams, not necessary Eliminate unnecessary exams, not necessary

examsexams

Estimated Lifetime Risk Estimated Lifetime Risk of Deathof Death

Lightning strikeLightning strike Bicycle accidentBicycle accident DrowningDrowning Motor vehicle Motor vehicle

accidentaccident Cancer (natural Cancer (natural

causes)causes)

Cancer, pediatric Cancer, pediatric (single CT)(single CT)

1 in 100,0001 in 100,000 1 in 10,0001 in 10,000 1 in 1,0001 in 1,000 1 in 1001 in 100 1 in 3-41 in 3-4

1 in 3000-30,0001 in 3000-30,000

Understand Understand institutional/population institutional/population

biasbias Patient populationPatient population

Prevalence of obesityPrevalence of obesity Relevant for US vs. CTRelevant for US vs. CT

Social/cultural conditionsSocial/cultural conditions Time of presentation/need for follow-upTime of presentation/need for follow-up

Age/gender of patientsAge/gender of patients Younger children/adolescent femalesYounger children/adolescent females

Institution resources/supportInstitution resources/support

My biasesMy biases

Awareness of cancer risks associated with Awareness of cancer risks associated with pediatric CT need to be raisedpediatric CT need to be raised

Alternatives to CT studies need to be exploredAlternatives to CT studies need to be explored If there is a low pre-test probability, neither If there is a low pre-test probability, neither

ultrasound nor CT study is an appropriate ultrasound nor CT study is an appropriate diagnostic imaging examinationdiagnostic imaging examination

If there is mid to high pre-test probability, If there is mid to high pre-test probability, andand it will likely change the course of treatment, it will likely change the course of treatment, CT is the study of choice for appendicitisCT is the study of choice for appendicitis

Pre-test probabilityPre-test probability

My bias against My bias against ultrasoundultrasound

There is still controversy about this exam, decades There is still controversy about this exam, decades after introduction, even among highly qualified after introduction, even among highly qualified radiologistsradiologists

The appendix is not found in ¾ of all examinationsThe appendix is not found in ¾ of all examinations When the appendix is not found, appendicitis can’t When the appendix is not found, appendicitis can’t

be excludedbe excluded When the appendix is found and appendicitis When the appendix is found and appendicitis

suspected, there is still a false positive rate of 25% suspected, there is still a false positive rate of 25% The immediate risk of patient harm from missed The immediate risk of patient harm from missed

ultrasound diagnosis is much more compelling than ultrasound diagnosis is much more compelling than the theoretical risk (and lower) long-term risk from the theoretical risk (and lower) long-term risk from medical radiationmedical radiation

My bias in favor of CT My bias in favor of CT studiesstudies

If the appendix is seen and normal, no If the appendix is seen and normal, no appendicitisappendicitis

If the appendix is not seen, but no If the appendix is not seen, but no other abnormalities identified, very other abnormalities identified, very low chance of appendicitislow chance of appendicitis

If the appendix is inflamed, then If the appendix is inflamed, then surgerysurgery

If the appendix is not seen but If the appendix is not seen but inflammation present, follow closelyinflammation present, follow closely

Trends for the futureTrends for the future

Better physician and patient educationBetter physician and patient education Clinical decision rules to minimize need Clinical decision rules to minimize need

for imagingfor imaging Awareness of the issues and time Awareness of the issues and time

constraints upon ED physicians for rapid constraints upon ED physicians for rapid diagnosisdiagnosis

Development of alternatives to CT studiesDevelopment of alternatives to CT studies Technical alteration of CT protocols to Technical alteration of CT protocols to

minimize radiation exposureminimize radiation exposure

ConclusionsConclusions

ConclusionsConclusions

There is still controversy concerning There is still controversy concerning diagnostic imaging for appendicitis in diagnostic imaging for appendicitis in pediatric patientspediatric patients

We are pro-active in keeping medical radiation We are pro-active in keeping medical radiation exposure as low as reasonable achievableexposure as low as reasonable achievable

The experience with our pediatric population, The experience with our pediatric population, emergency room physician expectations for emergency room physician expectations for accuracy, and surgical follow-up has led us to accuracy, and surgical follow-up has led us to recommend CT studies for appendicitis in the recommend CT studies for appendicitis in the appropriate clinical settingappropriate clinical setting