Sonography of normal cranial sutures.

OBJECTIVE: The purpose of this study was to describe the normal sonographic appearance and measurement of normal major cranial sutures in neonates and infants.

SUBJECTS AND METHODS: High-resolution sonograms of sagittal, coronal, and lambdoid sutures were obtained for two autopsy specimens and correlated with histologic sections obtained at identical locations. Also, 50 neonates and infants (0-5 months old [corrected age]) who had normally shaped craniums underwent sonography of the brain that produced normal findings. These neonates and infants also underwent sutural sonograms. The width and thickness of each of the major cranial sutures (sagittal, coronal, and lambdoid) were measured, with mean values established. Measurements were analyzed with paired t tests for interobserver variability. Linear regression was used for correlation of measurements with age.

RESULTS: With a scan plane perpendicular to the suture line, sonograms revealed sutures as hypoechoic gaps between two hyperechoic bony plates. On sonograms, sagittal sutures had an end-to-end appearance instead of the beveled junction seen throughout most of the coronal and lambdoid sutures. In the 50 patients, sonograms revealed the mean width to be 0.89 +/- 0.35 mm (mean +/- SD) for coronal sutures. 0.93 +/- 0.28 mm for sagittal sutures, and 0.96 +/- 0.39 mm for lambdoid sutures. On sonograms, mean thickness was 1.97 +/- 0.54 mm for coronal sutures, 1.88 +/- 0.56 mm for sagittal sutures, and 2.49 +/- 0.86 mm for lambdoid sutures. We found no interobserver variability (p < or = .05). With linear regression analysis, we found no correlation between suture width or thickness and patient age (r = .01).

CONCLUSION: In our study, high-resolution sonography proved to be a reliable and inexpensive technique capable of defining cranial sutures. Preliminary normative data obtained for cranial suture width and thickness showed no correlation with age in our population group. The normative data obtained will allow recognition of abnormal sutures, particularly synostotic or diastatic sutures.