Fig 8.

False positive result for reviewers 1 and 2: normal intradural vessels. Both reviewers thought that a fistula was present based on MR imaging (false positive, A–C) and based on MR imaging plus MR angiography (false positive, A–E).

A, Midsagittal T2-weighted fast spin-echo MR image shows normal size and signal intensity of the cord.

B and C, Contrast-enhanced T1−weighted MR images show no intrinsic cord enhancement. Enhancing linear segments (arrows) on the cord surface are noted.

D, Contrast-enhanced MR angiogram. Sagittal view maximum intensity projection image encompasses the midline vessels. The vessels (arrows) correspond to the anterior and posterior median veins.

E, Coronal view maximum intensity projection image encompasses approximately the anterior 10% to 20% of the canal and shows a midline vessel (arrow) with features of the anterior median vein.