Discerning the Helpful From the Hedge: Imaging Tips for

Abdominal Emergencies Emergencies

Angela M. Mills, MDMarch 5, 2012

Department of Emergency Department of Emergency

MedicineMedicineUniversity of Pennsylvania Health SystemUniversity of Pennsylvania Health System

DisclosuresDisclosures

None related to this talkNone related to this talk Allere, Inc. Allere, Inc.

– Research FundingResearch Funding Siemens Health Care DiagnosticsSiemens Health Care Diagnostics

– Research FundingResearch Funding EM Clinics of North America EM Clinics of North America

– HonorariumHonorarium

Hedge (hHedge (hĕĕj)j)

n.n.

4. 4. An intentionally noncommittal or An intentionally noncommittal or ambiguous statement.ambiguous statement.

v.intr.v.intr.

3. 3. To avoid making a clear, direct To avoid making a clear, direct response or statement.response or statement.

The American Heritage® Dictionary of the English Language

The HedgeThe Hedge

OverviewOverview

EpidemiologyEpidemiology Right upper quadrant painRight upper quadrant pain Pelvic painPelvic pain Right lower quadrant pain in Right lower quadrant pain in

pregnancypregnancy Contrast for suspected appendicitisContrast for suspected appendicitis

Over 8 million visits for abdominal pain in 2006Over 8 million visits for abdominal pain in 2006

Kocher et al. Ann Emerg Med. 2011.

13.9% all ED pts13.9% all ED pts

Kocher et al. Ann Emerg Med. 2011.

Almost 10x higher likelihood of CT in 2007 than 1996Almost 10x higher likelihood of CT in 2007 than 1996

Cat Scan

RUQ Pain:RUQ Pain:

Is It Acute Cholecystitis?Is It Acute Cholecystitis?

UltrasoundUltrasound

““……Recommend HIDA scan if there is Recommend HIDA scan if there is concern for acute cholecystitisconcern for acute cholecystitis””

Acute CholecystitisAcute Cholecystitis

EMBU comparable to RadEMBU comparable to Rad– Sensitivity 87% vs. 83%Sensitivity 87% vs. 83%– Specificity 82% vs. 86%Specificity 82% vs. 86%– Prior studies sensitivity 84-98%Prior studies sensitivity 84-98%

CT sensitivity 75%CT sensitivity 75%– Perforation, emphysematous chole, Perforation, emphysematous chole,

alternative diagnosesalternative diagnoses

Summers et al. Ann Emerg Med. 2010.Privette et al. EMCNA. 2011.

HIDAHIDA

Privette et al. EMCNA. 2011. Blaivas et al. J Emerg Med. 2007.

Nonfilling of GB Nonfilling of GB suggestive of ACsuggestive of AC– GB normally visualized GB normally visualized

within 30 minswithin 30 mins Sensitivity 90-100%Sensitivity 90-100% Specificity 85-90%Specificity 85-90%

99 pts, ED US and HIDA99 pts, ED US and HIDA Agreement 77% Agreement 77% 80% (12/15) +HIDA but –US, 80% (12/15) +HIDA but –US,

path agreed with USpath agreed with US 5 pts with normal HIDA but +US, 5 pts with normal HIDA but +US,

path agreed with USpath agreed with US

Blaivas et al. J Emerg Med. 2007.

Other HIDA IndicationsOther HIDA Indications

Symptoms of biliary dyskinesia Symptoms of biliary dyskinesia (chronic acalculous cholecystitis)(chronic acalculous cholecystitis)

Biliary tree anomaliesBiliary tree anomalies Evaluation of bile leak post choleEvaluation of bile leak post chole Sick ICU patient Sick ICU patient

– GN sepsis and unreliable examGN sepsis and unreliable exam– Unexplained leukocytosis on TPNUnexplained leukocytosis on TPN

Lambie et al. Clin Rad. 2011.

HIDA LimitationsHIDA Limitations

Does not image other structures Does not image other structures High bilirubin (>4.4 mg/dL) can High bilirubin (>4.4 mg/dL) can ↓↓ sensitivity sensitivity Recent eating or fasting for 24 hrs Recent eating or fasting for 24 hrs False negatives (filling in 30 min) in 0.5%False negatives (filling in 30 min) in 0.5%

– Filling between 30-60 mins associated with false-Filling between 30-60 mins associated with false-negative rates of 15-20% negative rates of 15-20%

False-positive results (10-20%) False-positive results (10-20%)

Blaivas et al. J Emerg Med. 2007.

Gallstones

www.cartoonstock.com

Pelvic Pain:Pelvic Pain:

Is It Ovarian Torsion?Is It Ovarian Torsion?

Computed TomographyComputed Tomography

““……Recommend US if there is concern Recommend US if there is concern for ovarian torsionfor ovarian torsion””

Chiou et al. J US Med. 2007.

100% OT had abnormal ovary on CT100% OT had abnormal ovary on CT

Moore et al. Emerg Rad. 2009.

CT with normal ovaries rules out torsionCT with normal ovaries rules out torsion

Moore et al. Emerg Rad. 2009.

US for Ovarian TorsionUS for Ovarian Torsion

Abnormal flow Abnormal flow – Sensitivity 44%, Specificity 92%Sensitivity 44%, Specificity 92%– PPV 78%, NPV 71%PPV 78%, NPV 71%

Accuracy 71%Accuracy 71%

Bar-On et al. Fertil Steril. 2010.Chiou et al. J US Med. 2007.

US for TOAUS for TOA

Sensitivity 56-93%Sensitivity 56-93% Specificity 86-98%Specificity 86-98% Only prospective study showed Only prospective study showed

Sensitivity 56%, Specificity 86%Sensitivity 56%, Specificity 86%

Lee et al. J Emerg Med. 2011.Tukeva et al. Rad. 1999.

CT for TOACT for TOA

No studies to evaluate Sens/SpecNo studies to evaluate Sens/Spec Ovarian masses, dilated tubes, free Ovarian masses, dilated tubes, free

fluid equally seen CT and USfluid equally seen CT and US Fat stranding better seen on CTFat stranding better seen on CT May be more difficult to May be more difficult to

differentiate pyosalpinx from T-O differentiate pyosalpinx from T-O complex or abscess by CTcomplex or abscess by CT

Horrow et al. US Quart. 2004.

CT for TOACT for TOA

Hiller et al. JRM. 2005.

Cat Scan

www.cartoonstock.com

RLQ Pain in Pregnancy: RLQ Pain in Pregnancy: Is It Appendicitis?Is It Appendicitis?

US for AppendicitisUS for Appendicitis

““……Recommend MRI if there is concern Recommend MRI if there is concern for acute appendicitisfor acute appendicitis””

US for AppendicitisUS for Appendicitis

Systematic review 14 studies (adults)Systematic review 14 studies (adults)– Sensitivity 81%, Specificity 80%Sensitivity 81%, Specificity 80%

Appendix not seen 25-35% of timeAppendix not seen 25-35% of time– Positive when diameter >6-7mmPositive when diameter >6-7mm

False negatives with perforation, False negatives with perforation, retrocecal or tip inflammation onlyretrocecal or tip inflammation only

Eresawa et al. Ann Int Med. 2004.Horn et al. EMCNA. 2011.

Kessler et al. Rad. 2004.

US for AppendicitisUS for Appendicitis

Systematic review Systematic review Imaging after normal or inconclusive Imaging after normal or inconclusive

US in pregnancyUS in pregnancy– CT: Sensitivity 86%, Specificity 97%CT: Sensitivity 86%, Specificity 97%– MRI: Sensitivity 80%, Specificity 99%MRI: Sensitivity 80%, Specificity 99%

Basaran et al. Ob Gyn Surv. 2009.

MRI Appendicitis in PregnancyMRI Appendicitis in Pregnancy

MRI vs. CT in PregnancyMRI vs. CT in Pregnancy

MRI has NPV 98% for acute abd painMRI has NPV 98% for acute abd pain Both show alternative diagnosesBoth show alternative diagnoses Retrospective study 1998-2005 greater Retrospective study 1998-2005 greater

increase in abd CT in pregnancyincrease in abd CT in pregnancy– 22%/yr/1,000 deliveries vs. 13%/yr22%/yr/1,000 deliveries vs. 13%/yr– Suspected appy most common indicationSuspected appy most common indication

Oto et al. Abd Imaging. 2009. Goldberg-Stein et al. Am J Roentgenol. 2011.

No consensus for imaging algorithm No consensus for imaging algorithm for abd pain in pregnancyfor abd pain in pregnancy

Radiology surveyRadiology survey– 96% respondents perform CT when 96% respondents perform CT when

benefit/risk ratio is highbenefit/risk ratio is high– MRI preferred 1MRI preferred 1stst trimester trimester– CT preferred 2CT preferred 2ndnd / 3 / 3rdrd trimesters trimesters

Jaffe et al. Am J Roentgenol. 2007.

Suspected Appendicitis: Suspected Appendicitis: Is Contrast Needed?Is Contrast Needed?

Contrast

Oral– Limits resp misregistration, motion artifacts

• Development of fast multidetector CT

– Protocols: 60-90 mins to opacify bowel IV

– Highlights differences btwn soft tissues– Risk of CIN, allergic reaction

Holmes et al. Ann EM. 2004.Stuhlfaut et al. Rad. 2004.

Retrospective, 183 pts– 81 oral contrast, 102 no oral contrast– Stat sig increased ED LOS

• 358 vs. 599 min, p<0.001

– Difference of 241 min >> 90 min

Huynh et al. Emerg Rad. 2004.

Systematic review of 23 studies– 19/23 prospective, total 3474 patients

• 1510 patients no oral contrast

– Final dx by path or clinical follow up

Anderson et al. Am J Surg. 2005.

7-study systematic review– 1060 patients– Final dx at surgery or min 2 week f/u – Noncontrast = no oral or IV

Sensitivity 93%, Specificity 96%– Comparable to prior published reviews

Hlibczuk et al. Ann Emerg Med. 2010.

www.cartoonstock.com

QuestionsQuestions