User Guide

Testing for low-contrast target detectability is performed as follows:

1. Apply coupling gel to the scanning surface or ll the water trough with tap

water.

2. Position the transducer above the cyst of interest and perpendicular to the

wires. You should be imaging the circular cross section of the cylinders.

3. Adjust the instrument settings (gain, TGC, output, etc.) as for a “normal” liver

technique. Record these settings for use on subsequent testing.

4. Align the probe so that the target is maximized.

5. Freeze the image and obtain a hard copy.

6. Observe the general appearance of each cystic structure. Note if there is ll in

and if you are able to see each of the masses.

7. A more detailed analysis can be performed by measuring the width and height

of each mass.

8. Record your observations.

GRAYSCALE CONTRAST SENSITIVITY

In the Model 040GSE contrast sensitivity is evaluated using 2 gray scale target

groups. The rst group, at 3 cm depth, is designed for probes of 5 MHz and pro-

vides grayscale contrast levels from –9 dB to +6 dB (relative to the background),

plus an extra hyperechoic target whose contrast level varies with the transducer

used. The second group, at 11.5 cm deep, provides grayscale contrast from -6 dB

to +6 dB, along with a hyperechoic target. See Table 2, page 17.

The dynamic range of an ultrasound imager can be evaluated using the gray scale

masses in conjunction with the cystic masses and the hyperechoic masses. Testing

of grayscale contrast is performed as follows:

1. Apply coupling gel to the scanning surface or ll the water trough with tap

water.

2. Position the transducer above the tumor of interest and perpendicular to the

wires. (The tumor should appear as a circular region).

3. Adjust the instrument settings (gain, TGC, output, etc.) as for a “normal”