EuroSafe Imaging 2020
Performed at one institution, Observational, Retrospective, Artifacts, Aneurysms, Technical aspects, Imaging sequences, CT, Neuroradiology brain, Head and neck, Action 3 - Image quality assessment based on clinical indications
H. Mellander, B. Ramgren, T. ullberg, V. Fransson, K. Ydström, J. Wasselius
Metal artifacts cause substantial limitation of the diagnostic value of brain computed tomography (CT) in patients with intracranial coils. The artifacts are partly caused by beam hardening i.e. dense materials or tissues that selectively filter out low energy x-ray beams resulting in a distorted attenuation in the surrounding tissues (1,2)
A new detector-based dual energy technique may reduce metal artifacts partly by using virtual monoenergetic reconstructions (VMIs), and partly by reduction of the beam hardening effect (1, 4). New iterative algorithms such as O-MAR (metal artifact reduction algorithm for orthopedic implants, Philips healthcare) may also mitigate the metal artifacts.
Patients with intracranial metal are often followed up with imaging after receiving the implant but may also be referred for other reasons. The benefits of CT as a choice of modality compared to MRI and conventional angiography include that it is not invasive, scan-time is limited and the availability is usually high. Metal artifact reduction in CT images would hence be of great clinical value.