7–11 October 2007, Florence, Italy Oral poster abstracts OP13.06 Fetal borderline cerebral lateral ventriculomegaly: a retrospective analysis of 74 cases S. Boito 1 , A. Righini 2 , L. Ramenghi 3 , L. Mandia 1 , P. Ficarazzi 1 , R. Fogliani 1 , G. Pardi 1 1 Obstetrics and Gynecology Inst., IRCCS Policlinico, Mangiagalli and Regina Elena Foundation, University of Milan, Italy, 2 Radiology and Neuroradiology, IRCCS Policlinico, Mangiagalli and Regina Elena Foundation, University of Milano, Italy, 3 Neonatal Intensive Care Unit, IRCCS Policlinico, Mangiagalli and Regina Elena, University of Milan, Italy Objectives: Our purpose was to evaluate the outcome of fetuses with borderline lateral cerebral ventriculomegaly. Methods: We retrospectively collected all cases of mild cerebral ventriculomegaly (transverse diameter of the atrium of the cerebral lateral ventricles between 10 and 15 mm) diagnosed antenatally between December 2001 and January 2007 at Mangiagalli Hospital. Associated ultrasonographic abnormalities including markers of aneuploidy, presence of chromosomal anomalies, structural malformations detected at birth, and clinical and neurologic outcome were recorded. Clinical outcome at the moment is available in 34 of the cases. Results: Seventy-four cases between 20 and 34 weeks of gestation fulfilled the inclusion criteria. In all cases a magnetic resonance imaging scan (MRI) in utero was performed after ultrasound diagnosis: in 64 cases MRI confirmed isolated ventriculomegaly and in 13 cases MRI revealed other associated anomalies; one case was a false positive. Two patients requested termination of pregnacy for fetal corpus callosum agenesis. Neurologic follow-up was normal in 14 out of 32 cases at a mean age of 38 (range 4 to 72) months. Of 18 cases with a poor outcome two had genetic syndromes and eight had neurological complications (four infants developed shunt-dependent hydrocephalus and four cerebral hemorrhage and periventricular leukomalacia). In the eight other cases, four had developmental delay. Ventricular atria ≥ 12 mm (n = 24) were more often associated with other fetal brain anomalies. Ventriculomegaly was bilateral in 39 fetuses and unilateral in 35 cases. The latter was more often associated with a poor neurological outcome (13/18 cases). Conclusions: Early and unexplained mild ventriculomegaly appears to have a good prognosis. If ventriculomegaly is persistent, prenatal management should be carried out to investigate chromosomal abnormalities, viral infection, and fetal cerebral parenchymal damage. OP13.07 How does MRI add to the diagnostic capability of sonography in the evaluation of fetuses with ventriculomegaly B. R. Benacerraf , T. S. Shipp, B. Bromley, J. K. Tannus, D. Levine Harvard Medical School, United States Objectives: To determine the contribution of MRI in evaluating fetuses with the sonographic diagnosis of ventriculomegaly (VM). Methods: Over 4 years, consecutive fetuses sonographically diag- nosed with VM and who underwent a prenatal MRI at one facility were included. The roles of MRI and follow-up ultrasound were tabulated. Karyotype and postnatal outcome were ascertained when possible. Results: Twenty-seven fetuses at 17–37 weeks had ultrasound detected VM (atria 10–29 mm), including 20 with mild VM (atria 10–12 mm). Group 1: 11 had isolated VM at ≤ 23 weeks (10 were mild VM), four of which reverted to normal by the third trimester. MRI detected cerebellar hypoplasia not seen by ultrasound in one fetus. Group 2: five fetuses had VM and ultrasound- suspected agenesis of the corpus callosum (ACC). Three of these had ACC on MRI and one had septo-optic dysplasia. MRI detected cerebellar hypoplasia in two cases, migrational abnormalities in two and porencephaly in one not seen by ultrasound. Group 3: six fetuses had normal second-trimester scans but developed VM that was noted after 24 weeks. Two had microcephaly and migrational abnormalities, one had an intracranial bleed seen by ultrasound with porencephaly noted on MRI only, two had stable mild VM at birth and one had enlarged cisterna magna on MRI. Group 4: four fetuses had VM and other CNS anomalies both on ultrasound and MRI: two with a cerebellar anomaly (one with kinked midbrain seen on MRI, not ultrasound), and one with heterotopia (with polymicrogyria seen on MRI not ultrasound), and one with an intracranial bleed seen with ultrasound and MRI (with porencephaly seen only on MRI). Group 5: one fetus presented for the first sonogram in the third trimester with VM, abnormal myelination and subependymal cysts diagnosed by MRI but thought to represent intracranial hemorrhages by ultrasound. Conclusions: While ultrasound is an accurate diagnostic modality for the evaluation of fetuses with VM, MRI does add important additional information, particularly regarding cerebellum and myelination disorders. OP13.08 Corpus callosum abnormalities: 2D, 3D ultrasound and MRI M. Signorelli , L. Franceschetti, F. Taddei, N. Palai, F. Prefumo, C. Groli University of Brescia, Italy Objectives: Visualization of the corpus callosum is often required in reference center ultrasound investigations. The aim of this study was to evaluate the role of 2D and 3D ultrasound and magnetic resonance imaging (MRI) in diagnosing the presence and the integrity of this cerebral structure. Methods: Fourteen cases of agenesis of the corpus callosum-ACC (10 complete and four partial) were studied prenatally using 2D ultrasound and MRI. For each case, three volumes of the fetal brain were acquired, and they were analyzed by a single operator, blinded to the results of 2D and MRI examination. Results: Prenatal 2D ultrasound diagnosis was confirmed postnatally in all cases. MRI correctly identified the 10 complete ACC, whereas one partial ACC was misdiagnosed as a complete form. Prenatal 3D ultrasound correctly identified nine out of ten cases of complete ACC (one case was misdiagnosed as partial), while it diagnosed correctly only one out of the four partial ACC: two were defined as normal and one was defined as total agenesis. Conclusions: The best visualization of the corpus callosum was obtained in a bidimensional sagittal median view of the fetal brain. MRI offers similar, but less clearly defined, imaging but is often interpreted by general radiologists lacking neurosonographic prenatal experience acquired by materno-fetal specialists dedicated to prenatal diagnosis. Using 3D ultrasound, the corpus callosum can be visualized in a very short time, but the imaging is less accurate, especially in the definition of borders and integrity of the organ, and thus it is not very useful in a referral center. OP13.09 Pulsed-wave Doppler of the middle cerebral artery in fetal brain abnormalities L. R. Pistorius , R. Gooskens, P. H. Stoutenbeek University Medical Centre Utrecht, Netherlands Objectives: The objective was to examine whether antenatal pulsed- wave Doppler indices of the middle cerebral artery have a prognostic value in fetuses with brain abnormalities diagnosed on ultrasound. Methods: A retrospective analysis was done of middle cerebral artery pulsatility index (MCA-PI) findings in fetuses with central nervous system (CNS) abnormalities diagnosed in a tertiary fetal ultrasound unit from 2000 to 2005 (inclusive). Ultrasound in Obstetrics & Gynecology 2007; 30: 456–546 499