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3D Ultrasound in
Gynecology
Dr. Juan Luis Alcázar
Department of Obstetrics and Gynecology
Clínica Universidad de Navarra. School of Medicine
University of Navarra, Pamplona, Spain
Ultrasound and the uterus
• Transvaginal ultrasound is a useful tool for
diagnosing uterine pathology such as uterine
myomas, adenomyosis and müllerian anomalies.
• It is quite difficult to differentiate myomas from
sarcomas using ultrasound
• Basic transvaginal ultrasound is a useful tool for
identifying endometrial pathology, but specificity
is moderate.
Ultrasound and the uterus
• A “normal” ultrasound in symptomatic women has
a high negative predictive value.
• Pulsed Doppler has no role.
• Power Doppler mapping may be useful, increasing
specificity but it is only reproducible when
performed by expert examiners
• Sonohysterography is especially useful when
intracavitary lesions are suspected
Ultrasound in adnexal masses
• B-Mode gray-scale ultrasound: – Subjective diagnosis
• Mean sensitivity: 91%
• Mean specificity: 75%
– Scoring systems
• Mean sensitivity: 89%
• Mean specificity: 78%
• Pulsed - color Doppler
– Great variability (> 140 studies in 20 years)
– Overlapping in velocimetric indexes
– Flow location: consistent parameter
– Meta-analysis (Kinkel,Radiology 2000)
• Mean specificity: 90%
– Decrease FP rate
– Problem: How to integrate it? Reproducibility?
What may 3D ultrasound add?
• 3D ultrasound offers unique ways to
evaluate uterine and endometrial pathology:
– Virtual Navigation
– TUI (Tomographic Ultrasound Imaging)
– VOCAL™ (Virtual Organ Computer Aided
anaLysis)
– SRI (Speckle Reduction Imaging)
– VCI (Volume Contrast Imaging)
– Off-line assessment
Kappa: 0.97
Kappa: 0.80
Kappa = 0.71
3D vascularity
What are we measuring?
Ultrasound assessment of tissue
vascularization • Conventional ultrasound
– Color / Power Doppler vessel mapping
– Pulsed Doppler indexes (RI / PI)
What 3D US adds?
• Vessels tree (vascular network)
Vascular Network.
Rationale
Vascular network. Problems
• Reproducibility: Just moderate.
– Sladkevicius UOG 2007
– Alcazar JUM 2008
K= 0.49
What 3D US adds?
• 3D power Doppler indexes. Virtual vascular “sampling”
3D-Power Doppler indexes
3D Power-Doppler
49 complex adnexal masses
with central vascularization
Manual sampling
Solid areas
5-cc spherical sampling could not
be performed in 19% of the cases
• Is it this true?
– Is VI related to number of vessels within ROI?
– Does FI reflect blood flow within ROI?
– Does VFI reflect tissue perfusion?
• Power Doppler = shift in signal amplitude (energy)
Which factors affect PD signal?
– Machine settings
• PRF. Gain. WF. Power (dB).
– Physiological-Rheological-Hemodynamic factors
• Volume flow. Hematocrit. Depth. Type of flow (Laminar,
Turbulent). Cardiac cycle. Heart rate.
Machine settings
Physiological-Rheological-Hemodynamic factors
Physiological-Rheological-Hemodynamic factors
3D-PD indexes and Number of
vessels
3D-PD indexes and Number of
vessels
3D-PD indexes and Flow Volume
4-fold increase in flow resulted just in 10% increase in FI
3D-PD indexes and Flow Volume
Summary of findings
• Machine settings, especially power, gain and PRF affect
significantly all 3D PD indexes.
• Depth affects significantly all 3D PD indexes.
• Hematocrit affects significantly all 3D PD indexes.
• VI seems to be related not only to vessel number but also to
volume flow within ROI
• FI does not seem to be related linearly to volume flow.
Explanations
• Factors not considered
– Type of flow.
– Blood pressure.
– Cardiac cycle.
• Hemodynamic phenomena
Explanations
• FACT: VI increases linearly as flow increases
• EXPLANATION
– Assuming parabolic laminar flow: Q = v·a
• Increase flow velocity
• Change vessel caliber
– Increase blood pressure Small vessels opened
Lower volume flow Higher volume flow
Higher nº of voxels detected
Explanations
• Cardiac cycle
– Do indices change in systole as compared with
diastole?
Explanations
• FACT: FI is poorly and not linearly related to flow
• EXPLANATION
– FI is just expressing mean quantification of change in
signal amplitude (color intensity)
– Is it FI absolutely independent from VI?
• “Dilutional effect” of voxels.
– Increasing VI may “dilute” FI value: More voxels detected but with
lower intensity, so disminish mean color intensity (FI)
– Hematocrit affects more intensely to FI than VI
• Effect on inflow hydrostatic pressure (IHP)
• Technical standardization is needed for both
gynecologic and obstetrics examinations.
Conclusions
• VI is related to number of vessels but also
to volume flow
• FI is poorly related to flow
• Standardization is essential for reproducible
results among different observers.
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