Diagnostic Performance of Decubitus Photon-Counting Detector CT Myelography for the Detection of CSF-Venous Fistulas

Definitive CVFs involving the IVVP in 2 separate patients, illustrating the complementary benefits of high-spatial-resolution and low kiloelectron volt VMIs. Both patients had a Bern score of 1. The first patient had no prior decubitus myelographic studies, while the second patient initially underwent negative decubitus DSM and negative decubitus EID CTM (not shown). In the first patient (A and B), an axial 0.2-mm T3D image (A) from PC-CTM demonstrates a left T6 CVF involving the IVVP (A, solid arrow). The draining vein is clearly separate from the thecal sac (A, dashed arrow), distinguishing it from a direct epidural leak. Concurrent axial 40-keV VMI reconstructed at the minimum allowed slice thickness of 0.4 mm with identical window/level settings demonstrates higher attenuation of the same finding (B, arrow), but the lower spatial resolution less clearly distinguishes the vein from the thecal sac (B, dashed arrow). In the second patient (C and D), axial (C) and coronal (D) 40-keV 0.4-mm VMIs from PC-CTM demonstrate a left T10 CVF of the IVVP (C and D, arrows). In this case, the 0.4-mm slice thickness was sufficient to distinguish the vein from the thecal sac. In both patients, the venous contrast washed away on subsequently obtained images (not shown).