Usefulness of monochromatic imaging with metal artifact reduction software for computed tomography angiography after intracranial aneurysm coil embolization

Abstract

Background Recently, a newly developed fast-kV switching dual energy CT scanner with a gemstone detector generates virtual high keV images as monochromatic imaging (MI). Each MI can be reconstructed by metal artifact reduction software (MARS) to reduce metal artifact. Purpose To evaluate the degree of metal artifacts reduction and vessel visualization around the platinum coils using dual energy CT with MARS. Material and Methods Dual energy CT was performed using a Discovery CT750 HD scanner (GE Healthcare, Milwaukee, WI, USA). In a phantom study, we measured the mean standard deviation within regions of interest around a 10-mm-diameter platinum coil mass on MI with and without MARS. Thirteen patients who underwent CTA after endovascular embolization for cerebral aneurysm with platinum coils were included in a clinical study. We visually assessed the arteries around the platinum coil mass on MI with and without MARS. Results Each standard deviation near the coil mass on MI with MARS was significantly lower than that without MARS in a phantom study. On CTA of a clinical study, better visibility of neighboring arteries was obtained in 11 of 13 patients on MI with MARS compared to without MARS due to metal artifact reduction. Conclusion: Dual energy CT with MARS reduces metal artifact of platinum coils, resulting in favorable vessel visualization around the coil mass on CTA after embolization.