Image Optimization 5-31
5.10.1 Note before Use
5.10.1.1 3D/4D Image Quality Conditions
NOTE: In accordance with the ALARA (As Low As Reasonably Achievable) principle,
please try to shorten the sweeping time after a good 3D imaging is obtained.
The quality of images rendered in the 3D/4D imaging is closely related to the fetal
condition, angle of a B tangent plane and scanning technique (Smart3D). The following
description uses the fetal face imaging as an example, the other parts imaging are as the
same.
îš„ Fetal Condition
z Gestational age
Fetuses of 24~30 weeks old are the most appropriate for 3D imaging.
z Fetal Body Posture
Recommended: Cephalic face up (figure a) or face aside (figure b).
NOT recommended: Cephalic face down (figure c).
a
b c
z
Amniotic fluid(AF) isolation
The region desired is isolated by amniotic fluid adequately.
The region to imaging is not covered by limbs or umbilical cord.
z The best condition is that the fetus keeps still. If there is a fetal movement in
Smart 3D or Static 3D imaging, you need a rescanning when the fetus is still.
îš„ Angle of a B tangent plane
The optimum tangent plane to the fetal face 3D/4D imaging is the sagittal section of
the face, or the coronal section. To ensure high image quality, you’d better scan
maximum face area and keep edge continuity.
îš„ Image quality in B mode (2D image quality)
Before entering 3D/4D capture, optimize the B mode image to assure:
z High contrast between the desired region and the AF surrounded.
z Clear boundary of the desired region.
z Low noise of the AF area.
îš„ Scanning technique (only for Smart3D)
z Stability: body, arm and wrist must move smoothly, otherwise the restructured 3D
image distorts.
z Slowness: move or rotate the probe slowly. The speed of linear scan is about 2
cm/s and the rotation rate of the fan scan is about 10°/s～15°/s.
z Evenness: move or rotate the probe at a steady speed or rate.
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