DISTAL LATERAL VENTRICULAR ATRIUM - REEVALUATION OF NORMAL RANGE

PURPOSE: To reassess the mean size of the lateral cerebral ventricular atrium in the fetus. MATERIALS AND METHODS: Measurements were obtaine d from axial ultrasound (US) images of 500 fetuses by using the standa rd criteria, and they were reviewed for consistency. Eleven fetuses ha d ventricular atrial measurements of 10 mm or more, and they were also followed up. Postnatal evaluation consisted of US examinations of the head in three patients and clinical examination of all 11 patients. R ESULTS: The mean size of the ventricular atrium was 6.6 mm with a stan dard deviation (SD) of 1.4 mm. However, the mean plus 2.5 SD would yie ld an upper normal limit of 10.1 mm. Findings at the postnatal examina tions of the 11 fetuses with isolated lateral ventriculomegaly (three with measurements of 13 mm or less and eight with measurements at 10 m m) were normal. CONCLUSION: Use of 10 mm (mean from this study plus 2. 5 SD) as the upper limit of normal for the ventricular atrial measurem ent should be continued. Measurements of 10 mm or above should prompt a careful search for associated fetal abnormalities and consideration of amniocentesis.