On the data acquisition, image reconstruction, cone beam artifacts, and their suppression in axial <scp>MDCT</scp> and <scp>CBCT</scp> – A review

<jats:sec><jats:title>Purpose</jats:title><jats:p>In the clinic, computed tomography (<jats:styled-content style="fixed-case">CT</jats:styled-content>) has evolved into an essential modality for diagnostic imaging by multidetector row CT (<jats:styled-content style="fixed-case">MDCT</jats:styled-content>) and image guided intervention by cone beam CT (<jats:styled-content style="fixed-case">CBCT</jats:styled-content>). Recognizing the increasing importance of axial <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content> in clinical and preclinical applications, and the existence of <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts in <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content> images, we provide a review of <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts’ root causes, rendering mechanisms and morphology, and possible solutions for elimination and/or reduction of the artifacts.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>By examining the null space in Radon and Fourier domain, the root cause of <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts (i.e., data insufficiency) in axial <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content> is analytically investigated, followed by a review of the data sufficiency conditions and the “circle +” source trajectories. The rendering mechanisms and morphology of <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts in axial <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content> and their special cases (e.g., half/short scan and full scan with latitudinally displaced detector) are then analyzed, followed by a survey of the potential solutions to suppress the artifacts. The phenomenon of imaged zone indention and its variation over <jats:styled-content style="fixed-case">FBP</jats:styled-content>,<jats:styled-content style="fixed-case"> BPF</jats:styled-content>/<jats:styled-content style="fixed-case">DBPF</jats:styled-content>, two‐pass and iterative <jats:styled-content style="fixed-case">CB</jats:styled-content> reconstruction algorithms and/or schemes are discussed in detail.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>An interdomain examination of the null space provides an insightful understanding of the root cause of <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts in axial <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content>. The decomposition of <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts rendering mechanisms facilitates understanding of the artifacts’ behavior under different conditions and the potential solutions to suppress them. An inspection of the imaged zone intention phenomenon provides guidance on the design and implementation of <jats:styled-content style="fixed-case">CB</jats:styled-content> image reconstruction algorithms and schemes for <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts suppression in axial <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content>.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>With increasing importance of axial <jats:styled-content style="fixed-case">MDCT</jats:styled-content>/<jats:styled-content style="fixed-case">CBCT</jats:styled-content> in clinical and preclinical applications, this review article can update the community with in‐depth information and clarification on the latest progress in dealing with <jats:styled-content style="fixed-case">CB</jats:styled-content> artifacts and thus increase clinical/preclinical confidence.</jats:p></jats:sec>