SIR 2024
Imaging
Evans Heithaus, MD
Interventional Radiologist
University of South Florida
Disclosure information not submitted.
Hugh Davis, MD
Interventional Radiologist
University of Florida College of Medicine - Shands
Disclosure information not submitted.
To review the technique, benefits, and limitations of 3D vessel overlay embolization guidance using a 4DCT system (Canon Medical, Otawara, Japan) in conjunction with catheter based CT pulmonary angiography in the embolization of pulmonary arterial venous malformations (pAVM) for patients with hereditary hemorrhagic telangiectasia (HHT).
Background:
Embolization of pAVMs can be technically challenging due to multiple factors including the complexity of vessel configuration as well as cardiac and respiratory motion. Angiographic roadmap techniques exist to aid operators in vessel selection, but these techniques are based on 2D angiography. This technique has limitations when changing obliquity of the fluoroscopy unit. Utilizing 4D CT catheter-based pulmonary CT angiography a 3D roadmap can be created and used for vessel overlay to aid in vessel catheterization and embolization. This technique can allow for overlay adaptation and correction with angulation changes in the fluoroscopy system real time without the need for additional angiography.
Clinical Findings/Procedure Details:
Patients with pAVM’s were treated in a procedure suite capable of 4DCT. Following selective catheterization of the pulmonary artery 4D CTA was performed via volume acquisition. The CT volume with the greatest degree of pulmonary artery contrast opacification was selected and uploaded to a separate workstation with embolization guidance software. The pAVM was marked as a “tumor” on the embolization software, and a central pulmonary artery was chosen as the catheter starting point. In all patients the embolization software correctly identified the feeding artery to the pAVM and allowed for a 3D roadmap to be created. The 3D roadmap was then sent to the monitor in the angiography suite. Using the 3D overlay feature, each of the feeding arteries was successfully catheterized. Correction for anatomy shift / patient movement was performed on all patients with alignment tools by matching the ribcage on the fluoroscopic image and the 3D roadmap. The vessel opacification was kept at a high enough level to allow for the operator to see the shift of the hilar vessels and diaphragm with respiration. The greatest advantage was seen with the real time adaptation of the 3D overlay images with changes in the fluoroscopy tube obliquity that obviated the need for additional angiography.
Conclusion and/or Teaching Points:
3D vessel overlay techniques for embolization guidance can aid operators treating complex pAVM’s, particularly in cases where feeding vessel catheterization requires multiple different obliquities to achieve vessel selection.