Lecture 17

Question 1

What is the effect of increasing the frequency?

Answer 1

Increasing the frequency increases the resolution (howver the trade-off is that this also decreases the image depth)

Question 2

What is the function of the TGC setting?

Answer 2

The TGC setting allows for attenuation to be compensated for by adjusting the brightness of deeper and darker structures on the ultrasound.

Question 3

Compare gain and power:

Answer 3

Gain adjusts the brightness of the diplay (done after image is formed-nothing to do with transducers)

The power changes brightness by adjusting the intensity of the sounds to the patient. Power can decrease resolution if it is set at a level too high. Should set as low as possible (or just DON’T FUCK AROUND WITH IT)

Question 4

What range is low contrast and what type of tissue should this be used for?

Answer 4

Low contrast refers to dB in the range of 55 to 80. Better for soft tissue

Question 5

What range is high contrast and what kind of tissue should this be used for?

Answer 5

Low dynamic range (35-50). Better for muskuloskeletal and also cardiac.

Question 6

Differentiate power and colour doppler (making sure to mention sensitivity):

Answer 6

Power doppler- much more flow sensitive. More sensitive for lower flow, deeper and smaller vessels.

Colour doppler - this is directional. It is less sensitive for flow detection and it is angle dependant.

Question 7

Breifly metion the importnat patient preparation consideration that need to be made prior to conducting an abdominal ultrasound:

Answer 7

1. Fast 12 hours prior to scan
2. Gas, food and faeces limit visibility
3. Avoid exciting patients
4. Hair removal and clean skin
5. Ispropyl alcohol and ultrasound gel

Question 8

Briefly describe how a dogs abdomen should be clipped in preparation for an ultrasound:

Answer 8

1. Xiphoid cartilage to pubis
2. Right angles triangle to the spine

Question 9

Breifly describe what the four transducer movements are:

Answer 9

1. Sliding - move without angling
2. Fanning - perpendicular side to side
3. Oscilltating (rolling) - pointing cranially and caudally in the same direction
4. Rotating - 90 degrees to the starting plane

Question 10

When ultrasounding in a transverse plane and contacting the ventral surface of the abdomen. The right side of the animal will appear on the ___(a)___ side of the screen.

When ultrasounding in a sagittal/longitudinal plane on the ventral side of the abdomen. The more cranial portion on the animal will appear on the __(b)____ side of the screen.

Answer 10

Aswer to both = left