Bedside Ultrasound of the Biliary Tract

1. Bedside Ultrasound of the Biliary Tract Gary Quick, M.D., FACEP

2. Objectives • Clinical indications for performing directed ED US • Approach to performing biliary tract imaging • Normal exam findings • Abnormal findings • Clinical impact • Problems/Pitfalls • Case Presentations

3. Diagnostic Modalities • Oral cholecystography (HIDA) • Computed tomography (CT) • Magnetic resonance imaging (MRI) • Ultrasound

4. Case History A 30 y.o. female presents with C/C of epigastric pain, nausea and vomiting for the past 6 hr. The pain is sharp, intermittent, and doubles her over at its peak intensity. The pain is located in the RUQ and radiates to her back. She had an appendectomy 5 yr. prior

5. Case History On physical examination she is afebrile with normal vital signs. She appears uncomfortable and vomits bilious material twice in the ED. She has midepigastric tenderness, no guarding, masses or hepatosplenomegaly and no CVA tenderness. Murphy’s sign is absent. Pelvic and rectal exams are normal.

6. Case History Within 5 min., a focused bedside US is performed by the EP. The GB is 3 cm in diameter with anterior wall < 2 mm thick. CBD measures 4 mm in diameter. There is a positive ultrasonic Murphy’s sign.The GB contains a large hyperechoic structure that casts an acoustic shadow

8. Clinical Indications for Bedside US of the Biliary Tract • Clinical presentation consistent with symptomatic cholelithiasis • Undifferentiated epigastric/RUQ pain • Jaundice

9. Clinical Impact of Bedside Biliary Tract Imaging • Rapid, accurate modality for diagnosis of cholelithiasis • Ultrasonic Murphy’s sign allows corroboration of physical findings • Fast and noninvasive • No radiation or contrast exposure • Performed at the bedside • Cost-effective procedure

10. Incidence of Biliary Tract Disease • Cholelithiasis affects > 15 million in U.S. • Contributes to 6-10,000 deaths annually • >500,000 cholecystectomies per year • Annual cost of surgery > $3 billion • Majority of gallstones clinically silent • 18-50 % become symptomatic over 10-15 yr

11. Performance and Accuracy of RUQ US by EP’s Kendall JL, Shimp RJ. Performance and interpretation of focused right upper quadrant ultrasound by emergency physicians, J Emerg Med 2001 Jul;21(1):7-13 EP RUQ US v. formal RUQ US 109 pts. enrolled: 51 with stones; 49 detected by EP’s. Sensitivity 96%.

12. Performance and Accuracy con’t. 58 without stones; 51 correctly identified by EP’s: Specificity 88% 83% of emergency studies completed in < 10 min. Conclusion: Gallstones accurately detected by EP’s in timely fashion.

13. Acute Cholecystitis • Correlation Among Clinical, Laboratory, and Hepatobiliary Scanning Findings in Patients With Suspected Acute Cholecystitis AJ Singer, Ann Emerg Med 1996;28:3:267-272. “No single or combination of clinical or laboratory findings at the time of ED presentation identified all patients with (acute cholecystitis).”

14. Acute Cholecystitis • Correlation Among Clinical, Laboratory, and Hepatobiliary Scanning Findings in Patients With Suspected Acute Cholecystitis AJ Singer, Ann Emerg Med 1996;28:3:267-272. “Liberal use of . . . . ultrasound is encouraged to avoid underdiagnosis of acute cholecystitis.”

15. If you use fever and an elevated white count as your criteria for diagnosing cholecystitis in the ED, you will misdiagnose 20% of these cases.

16. Congenital anomalies Cholelithiasis Acute and chronic cholecystitis Gallbladder sludge Gallbladder cancer Adenomyomatosis Bedside US Diagnostic Applications Bedside US facilitates diagnosis of:

17. Uncommon Gallbladder Anomalies • Agenesis • Hypoplasia • Hyperplasia • Total reduplication • Subtotal division of fundus • Phrygian cap • Septated gallbladder

18. Technical Considerations • Knowledge of US physics and machine operation • Anatomic relationships • Patient preparation • Patient positioning • Probe positioning

19. Skin Preparation and Probe Selection • Appropriate conductive medium (US gel) reduces skin artifact enhancing image quality • For general abdominal imaging use 3.5 MHz probe. 5 MHz may suffice in child

20. Patient Preparation • 6-8 hr. fasting period for elective scanning; not as critical for acutely ill pt • If pt has recently eaten • Small contracted gallobladder • Increased wall thickness • GB often distended in acute illness due to poor oral intake, abdominal pathology, or biliary tract obstruction

21. Patient Positioning • Usually begin with pt supine • Utilize at least two positions for exam • Provide better or multiple views of pathology • Demonstrate stone or sludge movement • Left or right lateral decubitus, left posterior oblique, partially upright, or prone

22. Probe Positioning • Function of personal preference, experience and patient body habitus • Employ liver as hepatic window. • Alternate window is retroperitoneum. • Anterior subcostal, coronal, right posterior oblique • Visualize the portal triad

23. Portal vein GB R kidney

24. Liver Gallbladder Biliary tree Head of pancreas Upper pole R kidney Portions of stomach and duodenum Hepatic flexure Vascular structures Retroperitoneal structures Right Upper Quadrant Anatomy

25. Quadrate liver lobe Gallbladder Right liver lobe Left liver lobe Cystic duct Hepatic artery Portal vein Common Bile Duct IVC RUQ Anatomy

26. RUQ Anatomy: GB Location • GB lies inferior to liver • Between the right and quadrate hepatic lobes • Hollow viscus in the gallbladder fossa • Consists of fundus, body, and neck • Neck tapers to cystic duct

27. Sonographic Appearance of Gallbladder • Fluid-filled structure • 3-layered wall • Strongly reflective outer layer • Minimally reflective inner layer • Anechoic layer between • Wall thickness < 2 mm. in 97%

28. Anatomy of Common Bile Duct • CBD is tethered to liver at juncture of right and left hepatic ducts and enters duodenum distally through ampulla of Vater • CBD passes across and then parallel to portal vein coursing along the hepatoduodenal ligament

29. CBD CBD • CBD internal diameter is < 4 mm in 98% of normal individuals • Cystic duct 1.8 mm diameter and 1-2 cm long Portal vein

30. CBD Scanning Tips • Roll pt 45° into left posterior oblique • Scan with transducer perpendicular to costal margin • Tweak transducer to image longest portion of portal vein . • CBD should lie anterior to (“above” on screen) portal vein. • CBD crosses then parallels the portal vein

31. Gallbladder Scanning Problems • Small liver, anterior GB, or bowel gas • Have pt sit up or roll to left to enlarge hepatic window. • Scan thin pt or anterior GB with 5 mHz transducer

32. Pathologic Conditions of the Biliary Tract • Cholelithiasis • Cholecystitis • Sludge • Cancer • Adenomyomatosis

33. Cholelithiasis • Prevalence: 6-10 % men, 12-20 % women • Three types of stone: Mixed cholesterol 80 % Pure cholesterol 10 % Pigment 10 % • 18-50% become symptomatic over 10-15 yr.

34. Processes of Gallstone Formation • Abnormal bile production • Bile stasis • Infection

35. Scanning Considerations: Cholelithiasis • Accuracy 90-95 % • Liver as acoustic window • Location: inferior hepatic surface, medial and anterior to kidney, lateral and anterior to vena cava

36. Ultrasonic Criteria for Cholelithiasis • Intraluminal brightly echogenic structure • Stones > 3mm will produce an acoustic shadow • Stones will usually seek gravitational dependency

37. Image Patterns: Cholelithiasis • Stones with shadowing • Stones without shadowing • Gravel • GB filled with stones • Floating stones as fluid level in bile • Adherent Gallstones • Dilation of common bile duct

38. Large stone with shadowing

39. Many small stones

40. Layer of gravel with shadowing

41. Cholecystitis • Represents both acute and chronic inflammation • Risk factors: obstruction and bile stasis • Bacterial growth common but secondary • Acute cholecystitis: fever, chills, RUQ pain and leukocytosis, jaundice, and positive Murphy’s. Acalculous cholecystititis 1- 5 %

42. Acute Cholecystitis Fever and Leukocytosis in Acute Cholecystitis Gruber PJ,Annals EM 1996;28:3,277-279 …”patients with acute cholecystitis in the ED frequently lacked fever and leukocytosis. The clinician should not rely on these findings in making the diagnosis of acute cholecystitis.”

43. Acute Cholecystitis • Age > 70 yr • Women < 40 yr: • 1.5 X greater for acute cholecystitis • 5 X greater for chronic cholecystitis

44. Acute Cholecystitis: Complications • Gangrenous cholecystitis • Gallbladder perforation • Pericholecystic abscess formation • Sepsis • Peritonitis • Ascending cholangitis • Peritoneal abscess formation • Cholecystoenteric fistula

45. Scanning Considerations: Cholecystitis • Cholelithiasis • Stones present in the majority of cases. • If no stones, consider acalculous cholecystitis. • Increased transverse GB diameter >4-5 cm • GB wall thickness > 4-5 mm (anterior wall) • Averages 5 mm in acute cholecystitis • Averages 9 mm in chronic cholecystitis

46. Additional Sonographic findings • Decreased echogeneity of the entire wall • Sonographic Murphy’s sign • Pericholecystic fluid • Diffuse, homogeneous echogeneity with GB lumen (pus in lumen or GB empyema)

47. Acute cholecystitis

48. Sonographic Murphy’s Sign • Place the probe directly over the gallbladder and apply pressure • Reproduction of the patients symptoms is highly suggestive of symptomatic cholelithiasis or acute cholecystitis • Look for gallbladder wall thickening, increased transverse diameter of the gallbladder and pericholestistic fluid indicating obstrcution and/or inflammation

49. Gallbladder wall thickening • Present in many non-inflammatory conditions • Post-prandial most common • Congestive heart failure • Starvation/hypoproteinemic states • Ascites • HIV

50. Thickened gb wall with stone