Atypical and equivocal sonographic features of the spinal cord in neonates.

Thanks to the wider use of sonography to examine the spinal content in the neonate, normal anatomy and anomalies may be detected easily. Yet, unusual sonographic patterns are also observed. These must be differentiated from true pathologies. During a prospective study of 103 neurologically asymptomatic neonates, atypical sonographic patterns were found in 16 patients, corresponding to normal variants in 13. Nine of these 13 patients presented with a widening of the distal part of the central echo complex (one had a dilated ventriculus terminalis). Nerve roots of the cauda equina were disposed asymmetrically in three patients; the spinal cord movements were still present. In two of these babies, this distribution was associated with thin arachnoid pseudocysts. One patient presented with transitorily hyperechoic and narrow subdural spaces, probably related to neonatal dehydration. None of the 13 patients showing normal variants required any treatment. The other 3 patients (of 16) presented with equivocal entities of unknown evolution: sonographic tethered cord, fibrolipoma of the filum terminale and epidural varices. Sonography is highly accurate in evaluating the spinal cord content and aids differentiation of normal and normal variants from equivocal or pathological entities.