3- and 4-Dimensional 3- and 4-Dimensional Ultrasound Imaging in Ultrasound Imaging in ObstetricsObstetrics

Curtis Lowery, M.D.Curtis Lowery, M.D.Professor and Section Head of MFMProfessor and Section Head of MFMMedical Director of ANGELSMedical Director of ANGELS

2D to 3D2D to 3D

The mental process of The mental process of converting 2D into 3D converting 2D into 3D images is not an easy images is not an easy one, and is dependent on one, and is dependent on individual skills and individual skills and training.training.Therefore, it is not Therefore, it is not surprising that the skills surprising that the skills involved in interpreting involved in interpreting ultrasound images are not ultrasound images are not uniform and vary between uniform and vary between practitioners.practitioners.

Ewigman BG, Crane JP, Frigoletto FD, LeFevre ML, Bain RP, McNellis D. Effect of prenatal ultrasound screening on perinatal outcome. RADIUS Study Group. N Engl J Med 1993; 329:821–827.LeFevre ML, Bain RP, Ewigman BG, Frigoletto FD, Crane JP, McNellis D. A randomized trial of prenatal ultrasonographic screening: impact on maternal management and outcome. RADIUS (Routine Antenatal Diagnostic Imaging With Ultrasound) Study Group. Am J Obstet Gynecol 1993; 169:483– 489. Grandjean H, Larroque D, Levi S. Sensitivity of routine ultrasound screening of pregnancies in the Eurofetus database. The Eurofetus Team. Ann NY Acad Sci 1998; 847:118–124.Levi S. Ultrasound in prenatal diagnosis: polemics around routine ultrasound screening for secondtrimester fetal malformations. Prenat Diagn 2002; 22:

Disparities in DiagnosisDisparities in Diagnosis

Methods of 3-D ImagingMethods of 3-D Imaging

Freehand acquisition using a conventional Freehand acquisition using a conventional 2-dimensional ultrasound (2DUS) 2-dimensional ultrasound (2DUS) Freehand (2DUS) acquisition using a Freehand (2DUS) acquisition using a conventional 2DUS transducer with conventional 2DUS transducer with position sensing position sensing Automated acquisition using dedicated Automated acquisition using dedicated mechanical volume probes mechanical volume probes Real-time 3D imaging using 2D array Real-time 3D imaging using 2D array transducerstransducers

There are three planes involved in the acquisition of a volume, A, B, and C. In this example of a scan with a fetus lying on its back the Planes are as follows:

1) A Plane - Transverse2) B Plane - Longitudinal3) C Plane - Horizontal

The three planes always maintain a 90-degree relationship to each other. No matter where you move the transducer or how you rotate acquired volumes the three planes will maintain their 90-degree relationship. Thus it is important to understand that any adjustment to one plane will affect the other two planes.

Tomographic Ultrasound Tomographic Ultrasound ImagingImaging

Benefits of 3DUSBenefits of 3DUS1)1) The ability to review volume data interactively after the The ability to review volume data interactively after the

patient has left the examination roompatient has left the examination room2)2) The possibility of using different planes of section for the The possibility of using different planes of section for the

evaluation of anatomic structures other than the original evaluation of anatomic structures other than the original acquisition plane acquisition plane

3)3) The possibility of rotating the volume data set so that The possibility of rotating the volume data set so that anatomic structures can be examined from different anatomic structures can be examined from different perspectivesperspectives

4)4) The availability of a variety of rendering methods that The availability of a variety of rendering methods that allow examiners to visualize different characteristics of allow examiners to visualize different characteristics of the same structure (eg, the same volume data set of the the same structure (eg, the same volume data set of the fetal back can reveal the external aspect of a fetal back can reveal the external aspect of a meningomyelocele when rendered in the surface mode meningomyelocele when rendered in the surface mode or, alternatively, the underlying bones when the volume or, alternatively, the underlying bones when the volume data set is rendered in the maximum-intensity mode)data set is rendered in the maximum-intensity mode)

Luís F. Gonçalves, MD,J Ultrasound Med 2005; 24:1599–1624

Benefits of 3DUSBenefits of 3DUS

5)5) Improved accuracy for volume measurements, Improved accuracy for volume measurements, including the possibility of measuring the including the possibility of measuring the volume of irregular objects volume of irregular objects

6)6) The possibility of standardizing ultrasound The possibility of standardizing ultrasound examinationsexaminations

7)7) The ability to transmit data over networks for The ability to transmit data over networks for consultation in tertiary care centersconsultation in tertiary care centers

8)8) The potential to use offline software programs The potential to use offline software programs as an interactive educational toolas an interactive educational tool

Fetal FaceFetal Face

Photography-Photography-like imageslike imagesFacial Facial movementsmovementsGood views Good views 70%70%Electronic fetal Electronic fetal scalpelscalpel

Fetal FaceFetal Face

Multiplanar and Multiplanar and rendered displaysrendered displaysMultiplanar: examiner Multiplanar: examiner to “navigate” through to “navigate” through the volume data set the volume data set simultaneously in the simultaneously in the 3 orthogonal planes3 orthogonal planesPrecise location of an Precise location of an anatomic structure or anatomic structure or abnormality abnormality

Demonstrations of 4-D offline Demonstrations of 4-D offline Volume Set AnalysisVolume Set Analysis

Combined 2DUS and 3DUSCombined 2DUS and 3DUS

N=96 facial cleftsN=96 facial cleftsConcordance between prenatal and Concordance between prenatal and postnatal diagnoses was observed in postnatal diagnoses was observed in 87.5%87.5%Underestimated the severity of the clefts in Underestimated the severity of the clefts in 8.3% (8/96) of the cases 8.3% (8/96) of the cases Overestimated in 4.1% (4/96).Overestimated in 4.1% (4/96).

Rotten D, Levaillant JM. Two- and three-dimensional sonographic assessment of the fetal face, 2: analysis of cleft lip, alveolus and palate. Ultrasound Obstet Gynecol 2004; 24:402–411.

Comparison of 2DUS and 3DUSComparison of 2DUS and 3DUS

N=31 facial cleftsN=31 facial cleftsAgreement between ultrasonographic Agreement between ultrasonographic diagnosis and neonatal outcomesdiagnosis and neonatal outcomes– 87.1% (27/31) of the 3DUS examinations87.1% (27/31) of the 3DUS examinations– 45.2% (14/31) of the 2DUS examinations45.2% (14/31) of the 2DUS examinations

Overestimated the severity of the defectsOverestimated the severity of the defects– 2DUS 41.9% (13/31) of the cases2DUS 41.9% (13/31) of the cases– 3DUS 9.7% (02/31) of the cases3DUS 9.7% (02/31) of the cases

Johnson DD, Pretorius DH, Budorick NE, et al. Fetal lip and primary palate: three-dimensional versus two dimensional US. Radiology 2000; 217:236–239.

Cleft LipCleft Lip

3-D Examination of Fetal Brain3-D Examination of Fetal BrainSeverity location and Severity location and extent of anomaliesextent of anomaliesVisualization of Visualization of corpus callosumcorpus callosumImprove visualization Improve visualization of cerebral blood flowof cerebral blood flowTopographic Topographic examination of fetal examination of fetal brainbrain

Evaluation Of the Fetal SpineEvaluation Of the Fetal Spine

A maximum intensity A maximum intensity projection mode ofprojection mode ofRotation of volume Rotation of volume setssetsMeasurement of the Measurement of the vertebral bodiesvertebral bodiesLevel of spinal defectLevel of spinal defect

3-D Views of Fetal Spine3-D Views of Fetal Spine

AchondrogenesisAchondrogenesis

Fetal Skeletal DysplasiasFetal Skeletal Dysplasias

2DUS and 2DUS and 3DUS and 3D 3DUS and 3D Helical CT 3DHelical CT 3D– Helical CT Helical CT

(94.1%)(94.1%)– 3DUS (77.1%)3DUS (77.1%)– 2DUS (51.4%)2DUS (51.4%)

Ruano R, Molho M, Roume J, Ville Y. Prenatal diagnosisof fetal skeletal dysplasias by combining twodimensional and three-dimensional ultrasound and intrauterine three-dimensional helical computertomography. Ultrasound Obstet Gynecol 2004; 24:134–140.

Congenital AnomaliesCongenital AnomaliesMixed ResultsMixed Results

Xu et al: higher visualization rates for Xu et al: higher visualization rates for congenital anomalies congenital anomalies – 3 DUS 78.0% [32/40]3 DUS 78.0% [32/40]– 2 DUS 92.7% [38/41]2 DUS 92.7% [38/41]

Scharf et al: 3DUS did not provide Scharf et al: 3DUS did not provide significant additional information (significant additional information (P P < .05)< .05)– 2DUS (68.3% [28/41]2DUS (68.3% [28/41]– 3DUS 97.5% [39/41]3DUS 97.5% [39/41]

Scharf A, Ghazwiny MF, Steinborn A, Baier P, Sohn C. Evaluation of two-dimensional versus three-dimensional ultrasound in obstetric diagnostics: a prospective study. Fetal Diagn Ther 2001; 16:333–341

Xu HX, Zhang QP, Lu MD, Xiao XT. Comparison of two-dimensional and three-dimensional sonography in evaluating fetal malformations. J Clin Ultrasound 2002; 30:515–525

Spatiotemporal Image Spatiotemporal Image CorrelationCorrelation

(STIC)(STIC)

Inversion Mode

2 DUS vs. 3 DUS of Fetal Heart2 DUS vs. 3 DUS of Fetal HeartIn skilled hands little advantageIn skilled hands little advantageTransmission of volume datasetsTransmission of volume datasets– Michailidis: 30 healthy fetusesMichailidis: 30 healthy fetuses

76.0% (23/30) 4 chamber view76.0% (23/30) 4 chamber view83.3% (25/30) right ventricular outflow tract83.3% (25/30) right ventricular outflow tract96.7% (29/30) left ventricular outflow tract96.7% (29/30) left ventricular outflow tract80.0% (24/30) long axis views80.0% (24/30) long axis views

Michailidis GD, Simpson JM, Karidas C, Economides DL. Detailed three-dimensional fetal echocardiography facilitated by an Internet link. Ultrasound Obstet Gynecol 2001; 18:325–328.

2 DUS vs. 3 DUS of Fetal Heart2 DUS vs. 3 DUS of Fetal HeartViñals et al: 4DUS with STIC Viñals et al: 4DUS with STIC Obstetricians with limited experience Obstetricians with limited experience Volume data setsVolume data sets100 fetuses examined100 fetuses examinedVisualization rates determined: Visualization rates determined: – 4-chamber 4-chamber – left and right ventricular outflow tractsleft and right ventricular outflow tracts– 3-vessel view3-vessel view– trachea views trachea views

Viñals F, Poblete P, Giuliano A. Spatio-temporal image correlation (STIC): a new tool for the prenatal screening of congenital heart defects. Ultrasound Obstet Gynecol 2003; 22:388–394.

Success rates: 81% - 100%Success rates: 81% - 100%

3-DUS First Trimester of 3-DUS First Trimester of PregnancyPregnancy

Embryonic brainEmbryonic brainNuchal Nuchal translucency translucency Faster scan Faster scan timestimesHigh frequency High frequency transducerstransducers

Volumetry in Early Pregnancy: CorrelationVolumetry in Early Pregnancy: CorrelationWith Abnormal Pregnancy OutcomeWith Abnormal Pregnancy Outcome

Volumetric Volumetric measurements:measurements:– Gestational sacGestational sac– Yolk sacYolk sac– EmbryoEmbryo– FetusFetus

Prediction of:Prediction of:– Spontaneous Spontaneous

miscarriagemiscarriage– AneuploidyAneuploidy

3-D Volumes of Limited Benefit!

Volumetry in Early Pregnancy: CorrelationVolumetry in Early Pregnancy: CorrelationWith Abnormal Pregnancy OutcomeWith Abnormal Pregnancy Outcome

Acharya and Morgan reported on a study of 81 Acharya and Morgan reported on a study of 81 patients with miscarriagespatients with miscarriagesMean gestational sac diameter/crown-rump length Mean gestational sac diameter/crown-rump length ratioratio– miscarriage, 3.3 [95% confidence interval (CI), 2.51–miscarriage, 3.3 [95% confidence interval (CI), 2.51–

4.08] 4.08] – normal pregnancies, 2.1 [95% CI, 1.67–2.63]normal pregnancies, 2.1 [95% CI, 1.67–2.63]– P P = .008= .008gestational sac volume/embryonic volume ratiogestational sac volume/embryonic volume ratio– miscarriage, 3.3 [95% CI, 2.51–4.08]miscarriage, 3.3 [95% CI, 2.51–4.08]– normal pregnancies, 459.5 [95% CI, 81.8–837.2]; normal pregnancies, 459.5 [95% CI, 81.8–837.2]; – P P = .023)= .023)

Acharya G, Morgan H. First-trimester, three-dimensional transvaginal ultrasound volumetry in normal pregnancies and spontaneous miscarriages. Ultrasound Obstet Gynecol 2002; 19:575–579.

32 Pregnancies mean32 Pregnancies meanGA of 12.3 ± 0.2 weeksGA of 12.3 ± 0.2 weeks

Basic fetal biometric Basic fetal biometric measurements measurements – Crown-rump lengthCrown-rump length– Biparietal diameterBiparietal diameter– Head Head

circumferencecircumference– Abdominal Abdominal

circumference circumference – Femur lengthFemur length

Fetal anatomic surveyFetal anatomic survey – Yolk sac, stomach, bladder Yolk sac, stomach, bladder

renal arearenal area– 4-chamber view of the 4-chamber view of the

heart heart – Cord insertionCord insertion– Choroid plexuses, cerebral Choroid plexuses, cerebral

ventriclesventricles– GenitaliaGenitalia– upper and lower upper and lower

extremities, hands, feet, extremities, hands, feet, digits digits

– NTT thicknessNTT thickness– Evaluation of the uterus Evaluation of the uterus

and placentaand placenta

Hull AD, James G, Salerno CC, Nelson T, Pretorius DH. Three-dimensional ultrasonography and assessment of the first-trimester fetus. J Ultrasound Med 2001; 20:287–293.

Fetal Anatomic and Biometric Survey byFetal Anatomic and Biometric Survey byFirst-Trimester 3DUSFirst-Trimester 3DUS

Complete biometric assessmentComplete biometric assessment– 3DUS 78.8% [126/160]3DUS 78.8% [126/160]– 2DUS 47.5% [76/160]; 2DUS 47.5% [76/160]; P P < .001< .001Nuchal translucency Nuchal translucency – 3DUS 96.9% (31/32) 3DUS 96.9% (31/32) – 2DUS 37.5% (12/32)2DUS 37.5% (12/32)Total scan timesTotal scan times– 3DUS 14.7 3DUS 14.7 ± 0.9 min. vs 2DUS 13.2 ± 0.4 min.± 0.9 min. vs 2DUS 13.2 ± 0.4 min.

P< 0.05P< 0.05

Transducer active timeTransducer active time– 3DUS 02.7 ± 0.2 min. vs 2DUS 14.7 ± 0.9 min. 3DUS 02.7 ± 0.2 min. vs 2DUS 14.7 ± 0.9 min.

P < .001P < .001

Nuchal Translucency Nuchal Translucency Thickness MeasurementsThickness Measurements

NTT <3.0 mmNTT <3.0 mm– Statistically significant overestimation of Statistically significant overestimation of

values from transvaginal and transabdominal values from transvaginal and transabdominal 3DUS3DUS

NTT >3.0 mmNTT >3.0 mm– Statistically significant underestimation of Statistically significant underestimation of

values from transvaginal and transabdominal values from transvaginal and transabdominal 3DUS3DUSWorda C, Radner G, Lee A, Eppel W. Three-dimensional ultrasound for nuchal translucency thickness measurements: comparison of transabdominal and transvaginal ultrasound. J Soc Gynecol Investig 2003; 10:361–365.

3D Volumetric Measurements3D Volumetric Measurements

Limbs to estimate: Limbs to estimate: fetal weight to 5% fetal weight to 5% birth weightbirth weight– 3DUS 20/30 fetal 3DUS 20/30 fetal

weight toweight to– 2DUS 6/30 2DUS 6/30

Lungs to predict: Lungs to predict: pulmonary hypoplasiapulmonary hypoplasia– ? Small studies? Small studies

Sonographic TomographySonographic Tomography5 volume data sets5 volume data sets– Fetal headFetal head– FaceFace– ChestChest– AbdomenAbdomen– Limbs Limbs

Examined by physicians not involved in Examined by physicians not involved in acquisitionacquisitionComplete studies 20/25Complete studies 20/25Scan times reduced by half with 3DUS Scan times reduced by half with 3DUS volume acquisitions (13.9 versus 6.6 volume acquisitions (13.9 versus 6.6 minutes minutes PP< .001)< .001)Benacerraf BR, Shipp TD, Bromley B. How sonographic tomography will change the face of obstetric sonography: a pilot study. J Ultrasound Med 2005; 24:371– 378.

Maternal BondingMaternal Bonding100 patients100 patientsRandomly assigned to 2DUS only or Randomly assigned to 2DUS only or 2DUS + 4DUS2DUS + 4DUSNo difference in positive response ratesNo difference in positive response ratesMaternal antenatal attachment scaleMaternal antenatal attachment scale– Quality and intensity of attachmentQuality and intensity of attachment– Global attachment scoreGlobal attachment score

Rustico MA, Mastromatteo C, Grigio M, Maggioni C, Gregori D, Nicolini U. Two-dimensional vs. two- plus four-dimensional ultrasound in pregnancy and the effect on maternal emotional status: a randomizeds study. Ultrasound Obstet Gynecol 2005; 25:468–472.

ConclusionsConclusions

Additional information Additional information in the diagnosis of in the diagnosis of congenital anomaliescongenital anomalies– facial clefts facial clefts – neural tube defectsneural tube defects– skeletal malformationsskeletal malformationsNew resources for New resources for fetal examinationfetal examination– MultiplanarMultiplanar– Anatomic slicingAnatomic slicing– Rendering modesRendering modes

Probable decrease in Probable decrease in examination timesexamination timesNew methods of fetal New methods of fetal biometrybiometryFetal organ volume Fetal organ volume measurementsmeasurementsVolume dataset Volume dataset acquisition and acquisition and transfertransferEducationEducation