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a Chapter 38 Three-Dimensional Doppler Ultrasound in Gynecology 565
bal patency test as part of the initial investigation.
Hysterosalpingo-contrast sonography using contrast
medium Echovist was performed in 67 women. Findings
on 2D gray-scale scanning and 3D power Doppler
imaging were compared. The first technique visualizes
positive contrast in the Fallopian tube; the
second demonstrates flow of medium through the
tube. Contrast medium Echovist produced prominent
signals on the 3D Doppler image. Free spill from the
fimbrial end of the Fallopian tubes was demonstrated
in 114 (91%) tubes using the 3D Doppler technique
and in 58 (46%) of tubes using conventional HyCoSy.
The mean duration of the imaging procedure was less
with 3D Doppler, but the operator time that included
post-procedure analysis of the stored information was
similar. A significantly lower volume of contrast medium
(5.9 Ô0.6 ml) was used for 3D Doppler in comparison
with that (11.2Ô1.9 ml) used for conventional
2D HyCoSy. The authors concluded that 3D
Doppler with surface rendering allowed visualization
of the flow of contrast through the entire tubal length
and free spill of contrast was clearly identified in the
majority of cases. The 3D Doppler method appeared
to have advantages over the conventional HyCoSy
technique, especially in terms of visualization of spill
from the distal end of the tube, which was achieved
twice as often with the 3D technique. Although the
design of the investigation did not allow the side effects
of the two techniques to be compared, the
shorter duration of the imaging and lower volume of
the contrast medium used suggested that the 3D Doppler
technique might have a better side-effect profile.
This technique allowed better storage of the information
for re-analysis and archiving than conventional
HyCoSy.
Whether salpingectomy affects ovarian function is
controversial. In Chan's et al. study, ovarian function
was assessed by antral follicle count, ovarian volume,
and ovarian stromal blood flow measured by 3D
power Doppler ultrasonography [20]. The objectives
of the study were to compare the ovarian function of
the surgically treated side with the non-surgically
treated side after unilateral salpingectomy performed
through laparoscopy or laparotomy for ectopic pregnancy.
Thirty-two patients with unilateral salpingectomy
performed for ectopic pregnancy were recruited:
18 through laparoscopy and 14 through laparotomy.
Ultrasound scans were performed in the
early follicular phase. Ovarian volume, antral follicle
count, and 3D power Doppler indices were comparable
between the surgically treated and the non-surgically
treated side in the whole group and in the laparotomy
group. The antral follicle count and 3D
power Doppler indices were significantly reduced on
the surgically treated side in the laparoscopy group.
Based on this study, ovarian function seems to be impaired
after laparoscopic unilateral salpingectomy at
short-term assessment.
Three-dimensional ultrasound, as any ultrasound
image, is not immune from artifacts. Nelson and coauthors
wanted to increase awareness of clinicians
and sonographers with respect to common 3D ultrasound
artifacts and to use this increased awareness to
avoid or reduce the occurrence of misdiagnosis in clinical
practice [21]. Patient 3D ultrasound data were acquired
using several different scanners and reviewed
interactively on the scanner and graphics workstations.
Artifacts were catalogued according to artifact origin.
Two-dimensional ultrasound (2D US) artifacts were
classified whether they were of a B-mode or color/
power Doppler origin and their presentation in the
original scan planes and the resulting volume re-sliced
planes and rendered images was identified. Artifacts
unique to 3D US were observed, noted, and catalogued
on the basis of whether they arose during acquisition,
rendering, or volume-editing operations. Acoustic artifacts
identified included drop-out, shadowing, etc., the
presentation of which depended on the relationship between
slice and imaging plane orientation. Color/
power Doppler artifacts were related to gain, aliasing,
and flash which could add apparent structure or confusion
to the volume images. Rendered images also demonstrated
artifacts due to shadowing and motion of adjacent
structures, cardiac motion or pulsatility of the
cardiac septum, or vessel walls. Editing artifacts potentially
removed important structures. Three-dimensional
ultrasound is prone to the same types of artifacts
encountered in 2D US imaging plus others unique to
volume acquisition and visualization. The consequences
of these diagnostically significant artifacts include
mimicking of abnormal development, masses, or
missing structures thus requiring careful study before
reaching a diagnosis.
The 3D reconstruction of ultrasound images has
become a widespread option in ultrasound equipment.
Specific softwares have become available and
3D reconstruction feasible since the early 1990s, particularly
since 1994. Several clinical applications are
feasible in some parenchymatous organs (such as
uterus or ovaries), hollow pelvic masses (e.g., ovarian
cysts), peripheral vessels (uterine artery and
branches), and new-formed vessels (e.g., tumor neovascularization)
or ectopic pregnancy. Moreover, tumoral
vessels in pelvic organs can be reconstructed
(Fig. 38.6). The introduction of echocontrast agents
and second harmonic imaging has permitted study of
normal and abnormal peripheral, central, and parenchymatous
vessels, with patterns similar to those
obtained with digital angiography. The spatial relationships
between the vascular structures of the
uterus, ovaries, and Fallopian tubes were studied with
3D Doppler ultrasound (Fig. 38.7). The applications