Ultrasound screening of the lambdoid suture in the child with posterior plagiocephaly.

BACKGROUND

The child with posterior plagiocephaly may have positional molding or unilateral lambdoid synostosis. Molding responds to conservative treatment, lambdoid synostosis requires surgical reconstruction. CT is diagnostic, but uses ionizing radiation, may need sedation, and the incidence of lambdoid fusion is only 2-3%.

OBJECTIVE

The purpose of this prospective study was to evaluate ultrasound as a screening test of lambdoid sutural patency using CT as the reference standard.

MATERIALS AND

METHODS

In total, 41 children having head CT examinations were enrolled over 6 months. Of those, 29 were referred for abnormal head shape and suspected synostosis, of whom two had lambdoid fusion; 12 were referred for indications not related to head shape and found to have a normal study. Ultrasound scanning and interpretation of the lambdoid sutures was performed blinded to the CT reference standard. The lambdoid suture was read as patent or fused if a hypoechoic gap could or could not be seen between the hyperechoic calvarial bones, respectively.

RESULTS

The mean sensitivity and specificity of ultrasound in distinguishing a patent from fused lambdoid suture by three blinded pediatric radiologists was 100% and 89%, respectively.

CONCLUSIONS

Sonography of the lambdoid sutures shows excellent preliminary promise as a screening test of lambdoid sutural patency.