Cranial Suture Evaluation on Routine Pediatric MRI

The efficacy of magnetic resonance imaging (MRI) for evaluating sutures has not been well studied. CT with 3-dimensional reformats is currently the preferred modality for imaging the major cranial sutures. The role of MRI is primarily is for evaluating the brain for any concurrent malformations. Our objective was to evaluate the reliability of MRI when compared to CT for evaluation of cranial sutures.

A list of 500 consecutive patients who underwent an MRI as well as a CT study was obtained. Studies were done between January 2011 and December 2016. The inclusion criteria required the 2 studies to be performed within 3 months of each other. All MRI studies were reviewed by a pediatric neuroradiologist to determine whether the sagittal, coronal, and lambdoid sutures were patent, fused or could not be assessed with confidence. In cases where a confident determination could not be made, the studies were reviewed with another pediatric neuro-radiologist and a decision made in concurrence. The CT scans were then evaluated in a similar fashion, after the MRI review was completed. The CT and MRI results were then compared to determine the accuracy of the MRI in assessing the sutures.

Mean age of the studied children was 8.54 years. Seventy-two percent of the sagittal sutures were seen. When seen the sagittal suture was correctly identified in 98% of cases as either fused or patent. The lambdoid suture was seen in 94.3% of studies and was correctly designated as patent or fused in 99.6% of that subset of cases. The coronal suture was seen in 66.3% of the cases and when seen was always (100%) correctly designated. The probability of agreement between MRI and CT increased with age. The probability of sutures which were not seen decreased with age. The false negative and positives remained low for all ages.

MRI is a viable tool for detection of cranial sutures. The 3-dimensional T1 Weighted sequence was particularly useful in suture evaluation. Although the visibility of sutures is inferior to that on a CT scan, if detected, the accuracy scan is fairly accurate in establishing fusion vs patency. It should be a part of routine surveillance on every pediatric neuro MRI study given the neurocognitive implications of incidental sutural synostosis.