1. Educational Objectives
- Imaging findings of biliary emergencies
- Technical Considerations of 64 MDCT:
- Contrast, reformations, radiation
- MRCP: when and how in the ER
- Current use of ERCP relative to MDCT and MRCP
- Pitfalls of all modalities
2. Introduction
- Biliary emergencies are:
- Common
- Come in many flavors
- Deceiving: frequent source of devastating mistakes
- Best friends:
- Caution
- Careful clinical evaluation
- Time
3. Context: Clinical
- Acute disorders affecting biliary tract are exceedingly common
- Biliary tract is often suspected cause of abdominal pain:
- Specific signs and symptoms
- Non-specific symptoms
- Biliary tract often foundto be unsuspected cause of abdominal symptoms
4. Ultrasonography
- Increasingly performed by non-radiologists
- Lack of supervision by physicians
- Practice: standard sets of static images/sweeps
- Common discrepancies with other tests/surgery
- Unlikely to change in near future
- Losing credibility
5. CT in Acute Abdominal Pain
- MDCT: ubiquitous, fast, notoperator dependant
- Most importantly… very powerful tool
- Radiologists less involved in imaging decision-making process: appropriateness of tests
- Result: large number of patients undergo CT as first test
- Numbers have dropped slightly…? transient
6. MR in the ER
- Also growing…
- MR scanners in or adjacent to ER
- Increasing clinical applications
- Neurological emergencies: trauma and non-trauma
- Orthopedic emergencies
- Obstetric emergencies
- Growing concern about untoward effects of CT-generated radiation: medical and non-medical community
7. Imaging Biliary Tract Emergencies
What are they?
- Acute biliary obstruction…obstructing stone
- Ascending cholangitis/other complications of stones
- Acute calculous cholecystitis
- Acute acalculous cholecystitis
- Gangrenous/emphysematous cholecystitis
- Gallbladder hemorrhage
- Gallbladder rupture
- Gallstone ileus
- Biliary tract trauma
8. Choledocholithiasis
- Occurs in 6-12% of patients undergoing cholecystectomy (at time of or subsequently)
- Imaging study for detection depends upon clinical presentation/index of suspicion:
- US: RUQ pain, biliary obstruction
- CT: Abdominal pain, fever/infection
- MRCP: Inconclusive US/CT, post-CCY
- ERCP: High pre-test probability
9. Gallstones and CT
- Detection depends upon:
- Stone composition: pigment/cholesterol, some are isoattenuating!
- Stone size/slice thickness: thin is better!
- Oral/IV contrast: both decrease performance!
- X-ray tube peak voltage: 140 kVp increases conspicuity (implications for dual ener- gy CT) Chan, C. et al. Radiology 2006;241:546-553
10. Performance of CT
| 1stAuthor | Year | Journal | Technique | Sensit | Spec |
| Neitlich J | 1997 | Radiol | HCT/I-/O- | 88% | 97% |
| Soto JA | 2000 | AJR | HCT/I-/O- | 72% | 84% |
| Pickuth D | 2000 | Hepatog | HCT/I-/O- | 86% | 98% |
| Moon JH | 2005 | Am J G | 4DCT | 40% | n/a |
| Anderson SW | 2006 | AJR | 4DCT/I-/O+
4DCT/I+/O+ |
70,87%
87,87% |
92,92%
83,88% |
| Anderson SW | 2008 | Radiol | 64DCT/ I+/O+ | 72,78% | 96% |
11. Ascending Cholangitis
- Acute infection → high WBC, fever, shock
- Biliary obstruction, stasis, +/-Dilatation
- Stones: most common cause
- CT:
- Biliary gas, Liver abscess
- Peri-biliary enhancement
- Bile duct wall thickening
- Peri-biliary fat stranding
12. Mirizzi’s Syndrome
- Impaction of gallstone in cystic duct or Hartmann pouch
- Inflammation leads to adherence with bile duct
- Imaging:
- Dilated common hepatic duct
- Normal caliber common bile duct
- Narrowing at junction of CHD and cystic duct
- ? Impacted stone
13. Acute Cholecystitis: Pathophysiology
- Calculous:
Obstruction→distension→edema→infection→↑blood flow→↑pressure→thrombo- sis→ ischemia→necrosis→rupture
- Acalculous:
- NO obstruction
- Typically hospitalized patients, debilitated, comorbidities
14. Acute Cholecystitis: Imaging
- Luminal distension >5 cm diameter
- Wall thickening >3 mm
- Wall/GB fossa hyperemia
- Stones: CT 75%, US 95%(?), MR (?)
- Pericholecystic fluid
- Inflammatory stranding pericholecystic fat
- Hyperemia adjacent liver parenchyma
- Murphy’s sign (US): 85% sensit, 35% spec
- All non-specific and prone to pitfalls
15. Clinical Scenarios and Imaging
- Typical symptoms: US, ?HIDA scan
- Atypical symptoms: US, CT
- Increasingly common:
- Nonspecific clinical findings andequivocal imaging findings
- Suspicious imaging findings without clinical correlate
- MR: problem solver, investigation of other conditions
16. Pitfalls
- Clinical/Imaging mismatch: additional tests, wait and repeat US, explore
- Acute cholecystitis but… no stone seen: Repeat US, look carefully
- FN and FP tests: no test is perfect
17. Summary
- Biliary emergencies are deceiving
- Recognize limitations of US for evaluating GB and bile ducts
- ? Value of positive US results (vs. negative or non-conclusive)
- Incorporate emergent MR into ER workflow
- Trauma: early use of HIDA