The accuracy of abnormal lumbar sonography findings in detecting occult spinal dysraphism: a comparison with magnetic resonance imaging

Abstract

Object The purpose of this study was to correlate lumbar ultrasound (LUS) and MRI findings in patients suspected of having occult spinal dysraphism (OSD). Methods Over a 5-year period, 1273 consecutive infants underwent an LUS study at a major pediatric tertiary referral center. Of these, 106 patients had abnormal LUS findings suggestive of an OSD, and 103 underwent subsequent MRI studies. The anatomical descriptions of the 2 studies were compared for agreement. Results The average age of the infants was 34 days at the time of the LUS study; OSD was suspected in these patients because of the presence of cutaneous stigmata and congenital defects. The most common anatomical descriptions from the LUS study included a thickened or fatty filum (32 cases), filum cyst (11 cases), and presence of a terminal ventricle or syrinx (9 cases). Using MRI findings as the standard reference, the sensitivity of LUS in detecting a thickened or fatty filum was 20%. The sensitivity of detecting an abnormal conus level at or below L-3 was 76.9%. Conclusions In the patient population chosen to undergo LUS studies, abnormal findings had poor sensitivity at detecting anatomical findings consistent with OSD.