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...
Description of activity and work performed
We performed a retrospective study of consecutive patients with intracranial coils who had undergone brain imaging at a Philips dual-layer IQon CT at our centre between November 21, 2017 and April 4, 2019. Patients with and without O-MAR reconstructions were included. The patients (n=38) were grouped and analyzed separately based on if O-MAR reconstructions were available (n=6) or not (n=32).
Objective image analysis: Regions of interests (ROIs) were placed in specific locations; artifact free white matter and artifact affected white matter distal and proximal to...
Conclusion and recommendations
Using VMI’s and the iterative artifact reduction algorithm OMAR can reduce metal artifacts and, depending on keVlevel the overall image quality and grey-white matter discrimination may also be improved which could result in an increased diagnostic quality.An example ofCI and monoenergetic reconstructions both with and witout OMAR may be viewed in figure 2.
H. Mellander; Lund/SE - nothing to disclose B. Ramgren; Lund/SE - nothing to disclose J. Wasselius; Lund/SE - nothing to disclose T. Ullberg; Lund/SE - nothing to disclose V. Fransson; Lund/SE - nothing to disclose K. Ydström; Lund/SE - nothing to disclose
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 Winklhofer S, Hinzpeter R, Stocker D, Baltsavias G, Michels L,Burkhardt JK, et al."Combining monoenergetic extrapolations from dual-energy CTwith iterative reconstructions: reduction...