Virtual non-contrast reconstructions improve differentiation between vascular enhancement and calcifications in stereotactic planning CT scans of cystic intracranial tumors

•VNC images enable a reliable iodine removal in blood vessels and brain parenchyma in stereotactic planning scans of cystic intracranial tumors.•VNC images increase diagnostic accuracy regarding the differentiation of vascular enhancement and wall calcifications of cystic intracranial tumors.•VNC images may provide an additional diagnostic benefit as compared to conventional images in stereotactic planning scans of cystic intracranial tumors. To assess the diagnostic value of spectral-detector CT (SDCT) derived virtual non-contrast images (VNC) for differentiation between vascular enhancement and wall calcifications of cystic intracranial tumors in contrast-enhanced stereotactic planning examinations. 48 patients with cystic intracranial tumors who underwent stereotactic SDCT examinations between 02/2017 and 02/2020 were retrospectively included. In each patient, two separate hyperattenuating structures along the cyst wall were defined as either enhancement or calcification, respectively, using reference MRI examinations. Quantitative analysis was performed ROI-based in conventional images (CI) and VNC. In the subjective analysis, two radiologists diagnosed the predefined peri-cystic structures in binary decisions as either enhancement or calcification using CI and the combination of CI and VNC, and rated diagnostic confidence, image noise and removal of iodine in VNC. Moreover, a potential diagnostic benefit of VNC was indicated. Attenuation in CI was higher as compared to VNC across all assessed ROI (all p