Image Optimization 5-57
5.10.6 STIC (Spatio-Temporal Image Correlation)
STIC function provides sectional images of high spatial resolution as well as good time resolution,
which is mainly used in fetal heart observation and cardiac hemodynamic exams.
STIC is an option.
Only probe D7-2E, D8-2E and D6-2NE support STIC function.
Acquired images are post processed to calculate a Volume Cine sequence representing one
complete heart cycle.
In order to achieve a good result, try to adjust the size of the volume box and the sweep angle to
be as small as possible. The longer the acquisition time, the better the spatial resolution will be.
The user must be sure that there is minimal movement of the participating persons (e.g., mother
and fetus), and that the probe is held absolutely still throughout the acquisition period.
Movement will cause a failure of the acquisition. If the user (trained operator) clearly recognizes a
disturbance during the acquisition period, the acquisition has to be cancelled.
One or more of the following artifacts in the data set indicate a disturbance during acquisition:
Sudden discontinuities in the reference image B
These are due to motion of the mother, the fetus or fetal arrhythmia during acquisition.
Sudden discontinuities in the color display
Motion of the mother, the fetus or fetal arrhythmia affects the color flow in the same way it
affects the gray image.
Fetal heart rate far too low or far too high
After acquisition the estimated fetal heart rate is displayed. If the value does not match the
estimations based on other diagnostic methods at all, the acquisition failed and has to be
repeated.
Asynchronous movement in different parts of the image
e.g., the left part of the image is contracting and the right part is expanding at the same time.
The color does not match the structure in the display format of grey mode
The color displays above or beneath the actual vessels.
Color ―moves‖ through the image in a certain direction:
This artifact is caused by a failure in detecting the heart rate due to low acquisition frame rate.
Use higher acquisition frame rate for better result.
1. In all of the above cases the data set has to be discarded and the
acquisition has to be repeated.
2. It is not allowed to perform the STIC fetal cardio acquisition if there is
severe fetal arrhythmia.
Diagnoses made only by assessing this 3D/4D acquisition are not
permitted. Every diagnostic finding has to be evaluated in 2D as well.
The user must be sure that no one of the participating persons (mother, fetus, and
user) moves during the acquisition. A movement of anyone will cause a failure of
the acquisition. If the user recognizes a movement during the scan, the acquisition
has to be cancelled!
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