(Ultrasound Review) According to Israeli obstetricians, the upper limit of normal for fetal ventricular atrium width should be 10 mm. This was determined through a prospective study combined with reanalysis of previous data. Assessment of the fetal head is an important component of the fetal morphology scan to rule out ventriculomegaly. Fetal outcome is substantially affected by ventriculomegaly, one of the most common sonographically detected abnormalities. The group from Lis Maternity Hospital in Tel Aviv reported their findings in the January issue of Journal of Ultrasound in Medicine.
"Currently, transverse measurement of the atrium is commonly suggested as the point of reference. A measurement of greater than 10 mm, which represents 2.5 to 4 (standard deviations) above the mean, has been considered abnormal in most series," they said.
They prospectively studied 427 normal pregnancies between 20 and 40 weeks’ gestational age, and re-evaluated a further 7,789 fetuses to determine normal lateral ventricle size by measuring the atrial width. Transabdominal scanning was performed using a 3.5-5 MHz curved array transducer. Transverse atrial width was measured three times in the axial plane slightly above the level of the thalami, and a mean measurement calculated.
"We conducted this study to obtain data on the normal upper limit of fetal ventricular atrial width in fetuses without abnormalities and, thus, to reanalyze the upper limit of these measurements in the literature," the authors explained. Previous research showed that mild ventriculomegaly (10-12 mm of dilatation) was associated with "a 3.7% rate of abnormal karyotypes and a 7.7% rate of developmental delay." They suggested that an atrial size of 10-12 mm as an isolated finding should be classified as borderline with follow-up and possible karyotyping recommended.
Fetal lateral ventricular width: what should be its upper limit?A prospective cohort study and reanalysis of the current and previous data
Almog, B et al.
Department of obstetrics and gynecology, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Israel
J Ultrasound Med 2003 January; 22:39-43
By Ultrasound Review
April 30, 2003
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