Agreement and Accuracy of the Dural Tail Sign for Differentiating Canine Meningioma From Glioma on MRI.

The dural tail sign (DTS) is an imaging sign used to categorize intracranial masses based on magnetic resonance imaging (MRI) axial localization. It is common in masses arising from outside the neuroparenchyma (extra-axial) and rare in masses arising from the neuroparenchyma (intra-axial). Accuracy and agreement reports of the DTS in canine meningioma are variable. Therefore, our objectives were to report agreement, sensitivity, and specificity of the DTS in dogs with a known diagnosis of meningioma or peripherally located glioma. This was a retrospective, secondary analysis, and cross-sectional study. Dogs with histologically confirmed meningioma or peripherally located glioma and 3T MRI were included. A total of 27 cases, 16 meningioma and 11 glioma, were included. Post-contrast T1-weighted images were provided to five blinded image evaluators in two separate randomized sessions separated by a 6-week washout period. Evaluators were asked to rate cases as "positive," "negative," or "indeterminate" for the DTS. All dogs with meningioma were rated positive for the DTS by a majority of evaluators in each session. The sensitivity and specificity for the DTS for the first session were 95% and 89.1%, respectively. Interobserver agreement for identifying the DTS was substantial (κ = 0.74), and intraobserver agreement across the two sessions was almost perfect (κ = 0.84). These findings indicate that, whereas not perfect, the DTS is accurate and reliable in the MRI differentiation of canine meningioma from glioma.