Diluted contrast media combined with high-resolution C-arm CT for evaluating apposition of flow diversions in a porcine model.

Background: In intracranial stenting, good stent apposition is crucial, and high-resolution C-arm computer tomography (CT) is utilized to assess whether stent apposition is complete. This study was aimed at finding optimal hypertonic or isotonic contrast media injection concentration for high-resolution C-arm CT to assess apposition of flow diversion (FD) after carotid artery stenting in swine.

Methods: Twelve FD stents were implanted into the left carotid artery of Bama swine through the endovascular method. During high-resolution C-arm CT scanning, 6%, 8%, 10%, 12%, and 14% dilution percentages of hypertonic contrast media (iopromide 370 mg/ml) and 10%, 12%, 14%, 16%, and 18% dilution percentages of isotonic contrast media (iodixanol 320 mg/ml) were separately injected. A radiologist and a neuro-interventional specialist evaluated and qualitatively scored the post-processed images, and intravascular ultrasound (IVUS) was used to verify the accuracy of these images.

Results: Overall, 12 FD stents were implanted into the left common carotid artery of 12 swine, with a technical success rate of 100%. The best reconstructed images used to observe stent apposition were achieved with iopromide diluted to a concentration of 12% (all  < .05) or iodixanol diluted to a concentration of 16% (all  < .05). Malapposition was noted in one case, and good apposition was noted in 11 cases. These results were consistent with IVUS observations.

Conclusion: Injecting iopromide or iodixanol diluted to 12% or 16% during high-resolution C-arm CT scanning, respectively, can help evaluate FD stent apposition and obtain optimal image quality.