• trade-off between
  • depth / penetration
  • resolution
• better signal when the signal is PERPENDICULAR to the target surface
• build a case
  • Think of USS as "building a case", finding evidence of where we are
  • have a mental image of the anatomy
  • then put the probe one
  • then move it and trace the nerves

• Linear array = HFL = High Frequency Linear
  • 6-13 MHz / 8-14 MHz
  • linear = high lateral resolution + maintains resolution with depth
    • will only see structures directly below probe
    • ideal for superficial soft tissue, neurovascular, procedural
• Curved array = Curvilinear probe = "abdominal probe"
  • 2-5 MHz = low frequency
  • similar to cardiac probe
    • wider footprint = better lateral resolution
• Phased array = "cardiac probe"
  • 1-5 MHz (low frequency)
  • good penetration, at the expense of resolution
  • small footprint = good for views inbetween ribs
• Endocavitary probe
  • 8-15 MHz = moderate frequency
  • curved array
  • ideal for intra-oral / trans-vaginal use

• 1: A-mode = Amplitude mode
  • rarely used
  • x-axis = depth
  • y-axis = amplitude
  • used for ophthalmologic/retinal USS and USS beam therapy
• 2: 2D = B-mode = Brightness mode
  • standard scanning mode
  • structures as seen as function of
    • brightness (echoic / anechoic)
    • depth
    • width
• 3: M-mode = Motion mode
  • narrow beam (as seen in B-mode) and displayed OVER TIME
    • a single scan line is emitted, received, and displayed graphically
    • useful for tracking motion / dynamic changes for a SPECIFIC POINT of an image OVER TIME
    • excellent temporal resolution (high frequency of data collected for a given area; high sampling frequency for a single line)
    • eg. for calculating TAPSE (tricuspic annular plane systolic excursion)
    • eg. fetal heart rate measurements
  • a single piezoelectric crystal = narrow beam
  • y-axis = distance from transducer
  • x-axis = time
• 4: Color Doppler
  • uses doppler shift = an induced change in frequency of returning echo to determine movement
  • superimposes color to show flow toward / away from probe
  • toward = red
  • away = blue
• 5: Power Doppler
  • similar to color doppler, but without assigning color to direction
  • shades of color to represent AMOUNT of flow
  • useful for low flow states
  • eg. IVC / hepatic vein
• 6: Spectral Doppler
  • either via pulse-wave (alternating) or continuous (simultaneous transmission and reception)
  • allows for assessment of FLOW VELOCITY at a specific point in the image, and displayed as a function of TIME
  • useful for cardiac TTE
  • eg. to quantify flow velocity across mitral valve

• slide = proximal / distal
• cut = left / right
• rotate = clockwise / anti-clockwise
• tilt = pivot at transducer head
• fan = pivot at transducer cord-end

1. Artifacts (horizontal A lines / vertical B lines) = interstitial syndrome
2. lung sliding
3. alveolar consolidation

WITH: venous analysis

https://radiopaedia.org/articles/m-mode-ultrasound

The BLUE Protocol, Chest 2008

REF__ Perioperative point of care ultrasound. Anaesthesiology.

http://www.tamingthesru.com/knobology