Purpose or Case Report: To compare the margin of filum terminale (FT) defined on longitudinal and transverse ultrasound (US) images, and to compare the thickness of FT measured on longitudinal and transverse US
Methods & Materials: The spinal canal US in 21 neonates and early infants performed between February 2016 and May 2016 were retrospectively reviewed. Three radiologists independently compare the margin of FT on each longitudinal and transverse US and scored into three scales: better on longitudinal image, better on transverse image, equal in both images. And the thickness of FT measured on each longitudinal and transverse US images were compared.
Results: Twenty-one patients were 10 boys and 11 girls with the median age of 12.7 days (range 1~67 days). Three readers selected transverse US as a better image to define the margin of FT in 13 cases, 12 cases, and 13 cases, respectively; longitudinal US in 3 cases, 1 case, and 1 case. Both transverse and sagittal US showed the same validity to define FT in 5 cases, 8 cases, and 7 cases. Intra-class correlations between 3 radiologists showed a high level of agreement (intraclass correlation coefficient 0.904). The thickness of FT was measured slightly larger on longitudinal US than transverse US (0.83 mm vs 0.82 mm).
Conclusions: Accurate measurement of FT thickness is important to find out the pathology on FT.This study revealed transverse US would be more helpful to define the margin of FT, and we could suggest to scan FT transversely first and then longitudinally.