Liver Ultrasound: Probe Positioning

Introduction

• Presented by Dr. Sam
• Focus: Ultrasound positioning for liver imaging

General Setup

• Ultrasound Probe Placement
  • Left side schematic representation of probe placement
  • Right side corresponding image
  • Components:
    • White box: ultrasound probe
    • Red dot: orientation marker (faces right side of the patient)
    • Dotted lines: right and left costal margins
    • Umbilicus included for reference

Initial Probe Position

• Patient Position: Supine
• Probe Position: Midline, transverse orientation, just below the costal margin
• View: Transverse view of the left lobe
• Anatomy Identified:
  • Left lobe
  • Left portal vein (hyper-echoic wall)
  • Ligamentum venosum
  • Caudate lobe (posterior to ligamentum venosum)

Adjusting for Visibility

• Deep Breath: Ask patient to take a deep breath if left lobe is not visible
• Rotate Probe: 90° clockwise for longitudinal orientation
  • Indicator directed towards patient's head
  • Move left of midline to scan left lobe thoroughly

Additional Structures

• Posterior to Liver
  • Pancreas
  • Splenic artery (small round anechoic structure)
  • Splenic vein (large rounded structure behind pancreas)
  • Stomach (alternating bright and dark layers)

Right Side Imaging

• Midline to Right:
  • Locate caudate lobe, posterior to ligamentum venosum
  • Inferior vena cava (IVC) on right of midline
  • Hepatic vein draining into IVC
  • Superior mesenteric vein (anechoic structure)
• Further to Right:
  • Porta hepatis
  • Portal vein with hyper-echoic walls
• Rotate Probe: Slight anticlockwise to view common bile duct
  • Measure diameter
• Right Lobe:
  • Move further right, keep probe slightly rotated anticlockwise
  • Sweep across to scan entire right lobe
  • Visible structures: gallbladder, portal veins, hepatic veins
  • Continue until kidney visible (usually midclavicular line)
  • Structures:
    • Right lobe
    • Right hepatic vein
    • Upper and lower poles of the kidney
    • Psoas muscle
• Deep Breath: If needed, to push the liver below the ribs

Scanning Hepatic Veins

• Probe Position:
  • Parallel to right costal margin, transverse orientation
  • Position just below costal margin
• Procedure:
  • Patient takes deep breath
  • Angle probe towards right shoulder
  • Scan under costal margin to view hepatic veins
  • Hepatic Veins:
    • Left hepatic vein (right half of image)
    • Middle hepatic vein
    • Right hepatic vein (left half of image)
  • All veins drain into IVC
  • Portal Veins: Hyper-echoic borders
  • Gallbladder: Visible

Final Imaging Steps

• Probe Alignment:
  • Similar to previous
  • Deep breath and sweep up and down
  • Angle towards patient's right shoulder
  • Locate Porta hepatis
  • Transverse View: At level of Porta hepatis
    • Portal vein, CBD anterior to it
    • IVC viewed in cross-section
• Inferior Scan:
  • Move inferiorly along costal margin
  • Probe parallel, slight angle towards right shoulder
  • Right Lobe: Transverse view
  • Structures:
    • Right kidney
    • Renal sinus fat (hyper-echoic structure)
    • Gallbladder
    • IVC (small anechoic structure)

Conclusion

• Note individual differences in organ location
• Probe positioning and protocol may vary

Closing

• Thank you for watching
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