Measurement Errors - Whale PE-12-025 User Manual

Measurement
STEP 5
STEP 6
STEP 7
7.8.4

Measurement Errors

Although the system has a very high accuracy in terms of scan and measure-
ment, users should be aware of the errors arising from ultrasonic signal char-
acteristics, scanning structure, tissue and physiological characteristics of
liquids.
In order to ensure the best possible measurement accuracy, the image zoom
proportion should be applied to the measurement.
In order to improve lateral resolution, select the proper probe according to
the depth range of the measurement structure.
During the measuring process, the following measurement errors shall be
taken into account:
When the ultrasonic beam axis is aligned with the blood flow, the measuring
error of flow velocity should be within ±5%.
In the process of diagnosis, the measurement data of the ultrasonic systems
must be used in combination with other clinical data, and no diagnosis
should be made only in terms of measurement data. When the data are ac-
quired by using the ultrasonic system, other factors should also be taken
into account. Analysis of these factors has shown that the accuracy of mea-
surement and further calculation largely depend on the quality image. In
Rev 1.00
On the soft menu, click IMT, and then select RT or LT from the IMT
list.
A sampling frame will be displayed on the monitor.
Note: RT represents the carotid which is at the right side of one's neck,
while LT represents the left one.
Drag the sampling frame to the measuring position and adjust its
size, and then press Set.
Note: If the sampling frame is frozen so that you cannot drag it,
press Trackball to activate it.
Note: To adjust the size of the sampling frame, press Set, and then
scroll the trackball.
On the main menu, select Calculate by pressing the two-way key on
the control panel, and then select Finish.
The measurement results will be displayed on the worksheet.
Distance measuring error: ± 3% or less;
Circumference measuring error: ± 3% or less;
Area measuring error: ± 6% or less;
Volume measuring error: ± 9% or less;
Chapter 7 - System Operation
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