Transcript Document

Bedside Ultrasound of the
Biliary Tract
Gary Quick, M.D., FACEP
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Objectives
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Clinical indications for performing directed
ED US
Approach to performing biliary tract imaging
Normal exam findings
Abnormal findings
Clinical impact
Problems/Pitfalls
Case Presentations
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Diagnostic Modalities
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Oral cholecystography (HIDA)
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Computed tomography (CT)
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Magnetic resonance imaging (MRI)
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Ultrasound
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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
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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.
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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
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Clinical Indications for Bedside
US of the Biliary Tract
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Clinical presentation consistent with
symptomatic cholelithiasis
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Undifferentiated epigastric/RUQ pain
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Jaundice
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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
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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 1015 yr
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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%.
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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.
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Acute Cholecystitis
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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).”
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Acute Cholecystitis
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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.”
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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.
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Bedside US Diagnostic
Applications
Bedside US facilitates diagnosis of:
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Congenital
anomalies
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Gallbladder sludge
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Gallbladder cancer
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Adenomyomatosis
Cholelithiasis
Acute and chronic
cholecystitis
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Uncommon Gallbladder
Anomalies
Agenesis
 Hypoplasia
 Hyperplasia
 Total reduplication
 Subtotal division of fundus
 Phrygian cap
 Septated gallbladder
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Technical Considerations
Knowledge of US physics and machine
operation
 Anatomic relationships
 Patient preparation
 Patient positioning
 Probe positioning
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Skin Preparation and Probe
Selection
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Appropriate conductive medium (US
gel) reduces skin artifact enhancing
image quality
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For general abdominal imaging use
3.5 MHz probe. 5 MHz may suffice in
child
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Patient Preparation
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6-8 hr. fasting period for elective scanning;
not as critical for acutely ill pt
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If pt has recently eaten
– Small contracted gallobladder
– Increased wall thickness
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GB often distended in acute illness due to
poor oral intake, abdominal pathology, or
biliary tract obstruction
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Patient Positioning
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Usually begin with pt supine
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Utilize at least two positions for exam
– Provide better or multiple views of
pathology
– Demonstrate stone or sludge movement
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Left or right lateral decubitus, left
posterior oblique, partially upright, or
prone
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Probe Positioning
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Function of personal preference, experience
and patient body habitus
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Employ liver as hepatic window.
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Alternate window is retroperitoneum.
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Anterior subcostal, coronal, right posterior
oblique
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Visualize the portal triad
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Portal vein
GB
R kidney
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Right Upper Quadrant Anatomy
Liver
 Gallbladder
 Biliary tree
 Head of
pancreas
 Upper pole R
kidney
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Portions of
stomach and
duodenum
 Hepatic flexure
 Vascular
structures
 Retroperitoneal
structures
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RUQ Anatomy
Gallbladder
Right
liver lobe
Left
liver
lobe
Hepatic
artery
Cystic
duct
Common
Bile Duct
Quadrate
liver lobe
Portal
vein
IVC
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RUQ Anatomy: GB Location
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GB lies inferior to liver
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Between the right and quadrate hepatic
lobes
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Hollow viscus in the gallbladder fossa
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Consists of fundus, body, and neck
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Neck tapers to cystic duct
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Sonographic Appearance of
Gallbladder
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Fluid-filled structure
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3-layered wall
– Strongly reflective outer layer
– Minimally reflective inner layer
– Anechoic layer between
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Wall thickness < 2 mm. in 97%
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Anatomy of Common Bile Duct
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CBD is tethered to liver at juncture of
right and left hepatic ducts and enters
duodenum distally through ampulla of
Vater
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CBD passes across and then parallel
to portal vein coursing along the
hepatoduodenal ligament
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CBD
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CBD internal
diameter is < 4 mm
in 98% of normal
individuals
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Cystic duct 1.8 mm
diameter and 1-2
cm long
CBD
Portal vein
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CBD Scanning Tips
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Roll pt 45° into left posterior oblique
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Scan with transducer perpendicular to
costal margin
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Tweak transducer to image longest
portion of portal vein .
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CBD should lie anterior to (“above” on
screen) portal vein.
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CBD crosses then parallels the portal
vein
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Gallbladder Scanning Problems
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Small liver, anterior GB, or bowel gas
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Have pt sit up or roll to left to enlarge
hepatic window.
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Scan thin pt or anterior GB with 5 mHz
transducer
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Pathologic Conditions of the
Biliary Tract
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Cholelithiasis
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Cholecystitis
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Sludge
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Cancer
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Adenomyomatosis
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Cholelithiasis
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Prevalence: 6-10 % men, 12-20 % women
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Three types of stone:
Mixed cholesterol 80 %
Pure cholesterol 10 %
Pigment 10 %
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18-50% become symptomatic over 10-15 yr.
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Processes of Gallstone
Formation
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Abnormal bile production
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Bile stasis
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Infection
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Scanning Considerations:
Cholelithiasis
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Accuracy 90-95 %
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Liver as acoustic window
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Location: inferior hepatic surface,
medial and anterior to kidney, lateral
and anterior to vena cava
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Ultrasonic Criteria for
Cholelithiasis
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Intraluminal brightly echogenic
structure
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Stones > 3mm will produce an
acoustic shadow
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Stones will usually seek gravitational
dependency
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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
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Large stone with shadowing
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Many small stones
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Layer of gravel with shadowing
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Cholecystitis
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Represents both acute and chronic
inflammation
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Risk factors: obstruction and bile stasis
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Bacterial growth common but secondary
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Acute cholecystitis: fever, chills, RUQ pain
and leukocytosis, jaundice, and positive
Murphy’s. Acalculous cholecystititis 1- 5 %
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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.”
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Acute Cholecystitis
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Age > 70 yr
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Women < 40 yr:
– 1.5 X greater for acute cholecystitis
– 5 X greater for chronic cholecystitis
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Acute Cholecystitis:
Complications
Gangrenous cholecystitis
 Gallbladder perforation
 Pericholecystic abscess formation
 Sepsis
 Peritonitis
 Ascending cholangitis
 Peritoneal abscess formation
 Cholecystoenteric fistula
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Scanning Considerations:
Cholecystitis
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Cholelithiasis
– Stones present in the majority of cases.
– If no stones, consider acalculous cholecystitis.
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Increased transverse GB diameter >4-5 cm
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GB wall thickness > 4-5 mm (anterior wall)
– Averages 5 mm in acute cholecystitis
– Averages 9 mm in chronic cholecystitis
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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)
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Acute cholecystitis
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Sonographic Murphy’s Sign
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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
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Gallbladder wall thickening
Present in many non-inflammatory
conditions
 Post-prandial most common
 Congestive heart failure
 Starvation/hypoproteinemic states
 Ascites
 HIV
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Thickened gb wall with stone
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Contracted gb w/ wall thickening
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Gallbladder Sludge
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Equals echogenic bile
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May represent biliary tract disease or
benign bile stasis with increased
pigment
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Clinical association with
hyperalimentation, hemolysis, fasting,
pregnancy, post-op state, and cirrhosis
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Gallbladder Sludge
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Differentiate from hematobilia, biliary tract
tumors, and purulent bile.
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May hide stones
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Found on 2% of RUQ US
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Serial studies if asymptomatic;
but treat aggressively if thickened wall,
pericholecystic fluid or sonographic
Murphy’s
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Scanning Considerations:
Sludge
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Sludge is slow-moving compared to stones
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When sludge is present, look for:
– Gallstones: floating or hidden within
– Cholecystitis: Murphy’s, wall-thickening
– Polyps: medium density; adherent to wall
– Malignancy: filled with solid masses or
focal masses within thickened walls.
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Sludge
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Gallbladder Cancer
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1-2 % of all GI malignancies
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75% of GB Ca patients have cholelithiasis
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Focal wall thickening, typically in fundus
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Lumen filled with tumor mass; wall calcified
(porcelain gallbladder)
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Scanning Considerations:
Cancer
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High rate of false positives and false
negatives
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Patterns aiding recognition:
– Gallbladder mass: complex, partially or
completely filling lumen
– Diffuse wall thickening
– Polypoid or fungating intraluminal masses
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Take Home Points
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Reposition the patient on their left side or
have them breathe to optimize imaging
windows
Stones can be incidental… presence of a
sonographic Murphy’s sign important
The acuostic shadow may be the only
songraphic sign of a stone
All echogenic masses/shadowing within the
GB or asymmetric wall thickening should be
followed up closely!
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