Summary: | Objective To analyze two different methods for performing
three-dimensional power Doppler angiography
(3D-PDA) vascular sampling in solid and cystic-solid
adnexal masses.
Methods Twenty-one 3D-PDA volumes from 18 consecutive
and unselected solid or cystic-solid adnexal masses
(13 malignant and five benign) were analyzed. A single
examiner (J. L. A.) acquired all the volumes according to a
predetermined scanning protocol. Two different observers
(one inexperienced and the other experienced) calculated
3D-PDA vascular indices (vascularization index (VI), flow
index (FI) and vascularization flow index (VFI)) from
solid tumor areas. First, manual sampling (Plane A, 15◦
rotation-step) was performed, and 1 week later 5-cm3
sphere sampling from the most vascularized area was carried
out. The observers made a record of any difficulty
that they encountered in delineating the solid areas of
tumors or in distinguishing true tumor vessels from preexisting
vessels, the time spent performing each analysis
was recorded and inter- and intraobserver reproducibility
was evaluated for each method using intraclass correlation
coefficients (ICC).
Results In four (19.0%) of the 21 volumes sphere
sampling could not be performed because it was not
possible to obtain a sphere smaller than 5.5 cm3. This
happened in cases in which image zooming was used when
acquiring the 3D volume. The inexperienced observer
encountered more difficulty, but not significantly more,
than the experienced observer when analyzing 3D-PDA
volumes both by manual sampling (29% vs. 14% of
cases) and 5-cm3 sphere sampling (35% vs. 18% of cases).
The mean time spent by the inexperienced observer was
significantly greater (P < 0.001) than that spent by the
experienced observer both for manual sampling (6.11 min
vs. 1.85 min) and 5-cm3 sphere sampling (2.93 min vs.
2.15 min). Contrary to the findings for the experienced
observer, the inexperienced observer required less time to
perform sphere sampling than they did manual sampling.
Interobserver agreement was high for both methods: ICC
for manual volume, 0.993; manual VI, 0.908; manual
FI, 0.913; manual VFI, 0.914; sphere volume, 0.949;
sphere VI, 0.954; sphere FI 0.850; and sphere VFI, 0.953.
Intraobserver reproducibility was also high, with all ICCs
above 0.99.
Conclusions Manual and 5-cm3 sphere sampling are
reproducible methods for 3D-PDA vascular sampling.
Caution is required when image zoom is used at the time
of acquiring the volume because this may prevent sphere
sampling. Difficulties found in performing both manual
and sphere sampling do not seem to significantly affect the
reproducibility of Doppler index calculations.
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