vascular pedicle itself. The twisted pedicle corresponds to the utero-ovarian ligament, suspensory ligament and meso-ovariaum containingovarian vessel and ovarian branch of uterine vessel. If tubal torsion iscombined, fallopian tube, broad ligament and adnexal branch of uterinevessel are also involved. The twisted vascular pedicle is seen as a roundstructure with multiple concentric stripes (coiling or target appearance),usually located in the inferior aspect of the mass, between the adnexalmass and uterine cornus. Flow signal within the twisted vascularpedicle may be identified as a characteristic “whirlpool sign” on colorDoppler US. When a preexisting adnexal mass is twisted, the mass mayshow eccentric wall thickening and septal thickening in the cystic mass,or hemorrhage within the mass. Occasionally, edematous ovarianstroma surrounding the ovarian mass may be demonstrable. When anormal ovary is twisted, it is enlarged with multiple peripheral cysts. Ifthe fallopian tube is involved, accompanying tubal thickening may berecognized as a tubular mass abutting or surrounding the adnexal mass.Doppler US is helpful for diagnosis of torsion. In the earliest phase oftorsion, venous flow is decreased and arterial flow shows a spiky,high-resistance pattern. In later stage, both arterial and venous flowswithin the ovary are absent. This presentation will discuss sonographicfindings of ovarian torsion with focus on the twisted vascular pedicle.Correlative CT and MR features will be presented as well.

3D/4D ULTRASOUND IN OBSTETRICS

1077

3D/4D ultrasound: Role in malformation detectionPlatt LD, David Geffen, School of Medicine at UCLA, United Statesof America

The purpose of this lecture is to demonstrate how the technologicalimprovements in ultrasound technology have improved over the pastseveral years and thus, leading to improving the clinician’s ability todiagnose fetal structural abnormalities or conditions prenatally. Im-provements in resolution and in the equipment’s performance haveprovided three-dimensional ultrasound imaging additional value overtwo-dimensional imaging. For example, three-dimensional imaging hasthe potential to offer clearer visualization of the fetal facial anatomyover two-dimensional ultrasound methods. Improvements in the imagerendering technology allows the sonologist to capture multiple imagescreating a volume dataset that can be rotated into a different plane andthe images further analyzed for fetal malformations. The ability toconsult with colleagues through the internet while providing all theultrasound information has improved dramatically over previous ultra-sound methods. These issues will be discussed.

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Examination of fetal organs using 3D multiplanar modeKalache K, Princess Anne Hospital, University of Southampton,United Kingdom of Great Britain and Northern Ireland

This presentation describes how computer tomography (CT)- and mag-netic resonance (MR)-like display modalities are now incorporated intomodern ultrasound systems. These new technologies are available asThree-Dimensional eXtended Imaging (3D XI)TM and includes Multi-Slice ViewTM, Oblique ViewTM and DynamicMRTM. Multi-SliceViewTM permit among others to show the three-dimensional ultrasoundvolumes as multiple sequential parallel planes. By means of ObliqueViewTM it is possible to slice the three-dimensional ultrasound volumesin various ways using intuitive interfaces. Data can be extracted eitheralong a linear plane or along a curved plane. By means of Dynamic-MRTM, several images are taken with different frequencies and fromdifferent angles and composed into a compound image. Artifacts cre-

ating shadowing or noise are reduced to a minimum, leading to sharperdepiction of the tissue margins. The presentation will be based onreal-life case studies illustrating the benefit of visualizing abnormalfetal structures by means of 3D eXtended ImagingTM. Topics coveredwill include: (1) how to use advanced multiplanar mode imagingmodalities in prenatal diagnosis; (2) application to difficult fetal brainanomalies; (3) visualization of subtle fetal facial malformations; (4)potential advantage as compared to standard fetal echocardiography.

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The role of 3D/4D ultrasound in complications of pregnancyMazor M, Smolin A, Soroka University Medical Center, Ben GurionUniversity, Israel

Three-dimensional (3D) and four-dimensional (4D) ultrasound diag-nostics are based on modern techniques of image acquisition and dataprocessing. The role of 3D/4D ultrasound in complications of preg-nancy is increasing during the last years. In this lecture will be pre-sented some of the aspects of the role of 3D/4D ultrasound in thediagnosis and management of complications of pregnancy such aspreterm labor, preterm PROM, altered fetal growth in IUGR andmacrosomia and twins gestations. 3D ultrasound imaging of uterinecervix can provide additional information to 2D ultrasound in describ-ing the cervical canal, the shape and size of the funnel, and otheruterine abnormalities. In addition, 3D/4D ultrasound may help in thefollow up and management of women with a short cervix and cerclage.This new application of 3D/4D can provide a more complete assess-ment of the uterine cervix in pregnant women at high risk for prematuredelivery. Another potential obstetric application of 3D/4D ultrasonog-raphy is in the examination of the developmental stage of the placentaand detailed visualization of placental abnormalities. Recently, 3D/4DDoppler ultrasound system has been suggested to have the advantageover conventional 2D sonography in determining abnormalities of theumbilical cord and in placental vascularity. Maldevelopment of theplacental villous tree and their blood vessels results in impaired fetalgrowth. Amplification of a new technique of imaging colour powerangiography with 3D reconstruction provides a tool to examine thevillous development during pregnancy in vivo. This approach shouldhelp us to differentiate between pregnancies complicated by fetalgrowth restriction due to placental factors (that will be associated withabnormal vascular fetal growth patterns) from those caused by fetalfactors. Recent studies have used 3D ultrasound for a better estimationof fetal weight since this technology can better measure volumes offetal structures such as thigh, arm and intraabdominal structures for theprediction of fetal weight. These 3D findings were reported to besuperior to 2D biometry system in the accurate assessment of fetalweight and prediction of macrosomia. It has a potential that 3D ultra-sonography may improve our knowledge in the management of diabe-tes in pregnancy. An additional possible application of 3D ultrasoundand power Doppler imaging techniques is the diagnosis and manage-ment of twin gestations and in particular in those complicated with twinto twin transfusion syndrome. There are reports of using the real time3D/4D ultrasonography in prenatal invasive procedures such as amnio-centesis and cordocentesis. It may be useful in determining whether ornot the needle is correctly placed during ultrasound-guided procedures.The images obtained are likely to reduce the number of complicationsassociated with difficult cases such as those with severe oligohydram-nios with or without PROM. Another important advantage of 4Dsonography is the information obtained in changes in fetal behavior inthe context of complications of pregnancy that were unavailable untilnow to obstetricians. Further accumulation of experience with thesenew techniques in the near future will increase the importance of3D/4D in the diagnosis and management of complications of preg-nancy.

P26 Ultrasound in Medicine and Biology Volume 32, Number 5S, 2006