Fundamentals of Scanning Test 1 (D)

What’s the penetration number for the linear array probe?

8 cm

Near field

Area nearest to the transducer

Which TGC will fix the near, mid, and far field?

Near field = top or higher TGC sliders

Mid field = middle sliders

Far field = bottom or lower sliders

Name the types of transducers & for which exams

Linear transducer - for vascular

Phased array or Sector transducer - for echo, abdominal (when penetration is needed)

Curvilinear transducer - for OBGYN/abdominal

Vector transducer - for abdominal (sometimes cardiac or intercostal scan)

Name the faces of the transducers

Sector, Vector, Phased Array : square face

Linear : rectangle face

Curvilinear : curved, convex face

What image shape/scan format does each transducer produce?

Linear → produces rectangular image

Curvilinear → produces sector (pie shaped) image with a CURVED top

Phased/sector → produces sector (pie shaped) image with a POINTED top

Vector → produces sector (pie shaped) image with a FLAT top

Frequency vs Resolution vs Penetration

Low frequency = deeper penetration, but lower resolution

Higher frequency = less penetration, but higher resolution

What to label/annotate on images?

Label

• the side of the patient being scanned (left/right)

• the organ

• location details (proximal, mid, distal)

• transducer orientation (transverse or sagittal)

• patient position (supine or prone)

Role of a sonographer

Provide diagnostic images for a physician

A-mode

Amplitude mode

Not used often today, except ophthalmology

Spikes represent strength of returning echoes

B-mode

Brightness mode

Range of whiteness from black to white

Echoes create spots that make image

Gray scale (256 shades of gray) that create image

M-mode

Motion of structures along a signal graph overtime

Graphs depth vs. time of structure

Used in cardiac scans

Pulser/transmitter

Provided electrical excitation to the crystals in transducer

What’s the Piezoelectric effect?

Ability for the energy (crystals in transducer) to go from electrical energy to mechanical and back

What’s another name for Overall Gain?

2D Gain or Amplification Gain

What does adjusting overall gain do?

Adjusts overall image brightness

What does adjusting the TCG do?

Adjusts the brightness in a specific area of the image

What does adjusting the focus do?

Allows more focus/clarity on a specific area (better quality in that area)

What does adjusting depth do?

Adjusts the depth of ultrasound wave

Decreasing depth allows you to focus / hone in on specific structure

Where is depth indicated on an image?

Indicated by dashes on the screen on the side of an image

What’s the focal zone?

Ability to focus transducer at various depths for better resolution

How to adjust the focus?

Use focus knob: place the triangle symbol (CARET) at or just below the area of interest to focus

Function of Trackball

• Allows you to navigate screen (similar to computer mouse)

• Annotations

• Focus

• Gain

• Cineloop

• Calipers

• Change size of scan sector/color box

Frequency of linear transducers

5 to 18 MHz

Frequency of curvilinear array transducers

2 to 5 MHz

Frequency of sector/phased array transducers

3 to 5 MHz

Frequency of vector transducers

2 to 5 MHz

Why do you annotate?

Identifies anatomy & pathology

Provides orientation & views for referencing

What’s another term for Dynamic Range?

Log compression

What is Dynamic Range?

Number of shades of gray displayed (keep it around 60 dB)

Narrow Dynamic Range vs. High Dynamic Range

Narrow dynamic range = high contrast image, very black & white, grainy

High dynamic range = low contrast image

Why would you use TGC versus overall gain?

To adjust the brightness in a specific area

Near Zone vs. Far Zone?

Near zone = area closest to transducer; higher quality

Far zone = area furthest from transducer; lower quality due to depth

Near Gain vs. Far Gain?

Near Gain = controls brightness at top of image

Far Gain = controls brightness at bottom of image

Tips for holding probe properly

• Hold it like a pencil, relaxed

• Drop & relax elbow

• Relax shoulders

• Keep hand underneath probe

• Hold hand as close to body as possible

• Rest hand on patient (get permission)

• Hang cable on machine or wrap around wrist

What are matrix transducers?

Special transducers that allow 3D/4D imaging

Various MHz

Has columns and rows of crystals

What are multihertz transducers?

Operates over a range of frequencies without needing to switch transducers