Ultrasound Review

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Ultrasound Review
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Ultrasound Physics

• Sound is a mechanical wave, which requires a
  medium in which to travel
• Speed is determined by the density and stiffness
  of the medium
• Increased speed with stiffer media
• Attenuation, a decrease in intensity and
  amplitude, occurs as sound waves travel through a
  medium

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Ultrasound Modes

• B-mode (brightness mode)
• Provides structural information in a
  2-dimensional image
• M-mode (motion mode)
• Captures returning echoes in only one line of the
  B-mode image and displays them over a time axis
• Doppler Mode
• Examines the characteristics of direction and
  speed of tissue motion and blood flow and
  presents them in audible, color, or spectral
  displays
• Color Doppler
• Power Doppler
• Spectral Doppler

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• B-mode

• M-mode

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Ultrasound Probes

• Large Convex Probe
• Transabdominal sonongraphy
• Microconvex Probe
• Transabdominal or transthoracic sonography
• Linear Probe
• Vascular sonography or superficial soft tissue
  structures
• Intracavity Probe
• Transvaginal
• Sector Probe
• Transthoracic sonography

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The FAST exam

• Focused Assessment with Sonography in Trauma
• The purpose of bedside ultrasound in trauma is to
  rapidly identify free fluid (usually blood) in
  the peritoneal, pericardial, and pleural spaces
• Emergency physicians began using it in the 1980s
  and it is now the initial imaging test of choice
  for trauma care in the U.S.
• Per ATLS protocol, it is to be performed
  immediately following the primary survey

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Indications for FAST

• Blunt/Penetrating Cardiac Trauma
• Pericardial effusion
• Severe ventricular dysfunction
• Blunt/Penetrating Abdominal Trauma
• Intraperitoneal bleeding
• Chest Trauma
• Hemothorax
• Pneumothorax

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Subxiphoid View
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Parasternal Long Axis View
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Right Coronal/ Intercostal Oblique Views
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Fluid in Morrisons Pouch
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Left Coronal/ Intercostal Oblique Views
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Longitudinal Pelvic Views
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Free Fluid in the Pelvis
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Transverse Pelvic Views
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Abdominal Aortic Aneurysm

• Seagull Sign
• Celiac trunk branches into the hepatic and
  splenic arteries
• IVC
• On the right
• Usually larger with thinner walls and compressible

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Abdominal Aortic Aneurysm
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Gallbladder

• Use curvilinear abdominal probe
• Subcostal Sweep
• Generally the most effective window
• Sweep the probe in an inferior and lateral
  approach along the costal margin
• X minus 7 approach
• Intercostal approach approximately 7 centimeters
  to the right of the xiphoid process
• Flattening the probe approach
• Flatten the probe against the abdomen while
  aiming toward the right shoulder

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Gallbladder Pathology

• Gallstones/Sludge
• Sonographic Murphys Sign
• Gallbladder Wall Thickness
• Measured at the most narrow point of the anterior
  wall in the short axis
• Normal wall is less than 4 mm
• Pericholecystic Fluid
• Dilated Common Bile Duct
• Normal width is 4mm

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Kidney
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Hydronephrosis

• Degrees
• Mild

• Moderate
• Severe

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Renolithiasis
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Renal Cysts