In Vivo Discrimination of Iodine and Tantalum-Based Liquid Embolics After Intracranial or Spinal Embolization Using Photon-Counting Detector CT.

Purpose: In vitro differentiation of iodine and tantalum-based liquid embolics post-embolization can be achieved using spectral computed tomography. This study evaluates the in vivo ability of clinical photon-counting computed tomography (PCD-CT) to distinguish these embolic agents in patients undergoing endovascular treatments for cerebrovascular and spinal pathologies.

Methods: This retrospective study included 25 patients treated between April 2021 and March 2024, who underwent PCD-CT imaging post-embolization for intracranial arteriovenous malformations (AVM), dural arteriovenous fistulas (dAVF), spinal tumors, or middle meningeal artery (MMA) embolization for chronic subdural hematomas (cSDH). Imaging analysis involved iterative reconstruction, using conventional images (CI), iodine maps (IM), and virtual non-contrast (VNC) series. Two blinded neuroradiologists assessed the suppression quality of the embolic agents on a Likert scale.

Results: Of the 25 patients, 22 underwent intracranial and 3 spinal embolizations. The differentiation between iodine and tantalum-based embolics achieved 92% accuracy for reader 1 and 88% for reader 2, with a Cohen's kappa coefficient of 0.92 indicating high inter-reader agreement. Iodine-based agents were moderately suppressed, whereas tantalum-based agents exhibited superior suppression. Errors arose from mistaking suppressed platinum coils for tantalum-based embolics. Hemorrhage detection accuracy was high, with a Cohen's kappa of 0.92.

Conclusions: PCD-CT effectively differentiates between iodine- and tantalum-based embolics in vivo, demonstrating high diagnostic accuracy and inter-reader reliability. This capability facilitates improved post-procedural assessment and may enhance the management of endovascularly treated patients by reducing imaging artifacts and aiding in hemorrhage detection.