Metal artefact reduction from dental hardware in carotid CT angiography using iterative reconstructions
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To determine the value of a metal artefact reduction (MAR) algorithm with iterative reconstructions for dental hardware in carotid CT angiography.
Twenty-four patients (six of which were women; mean age 70 ± 12 years) with dental hardware undergoing carotid CT angiography were included. Datasets were reconstructed with filtered back projection (FBP) and using a MAR algorithm employing normalisation and an iterative frequency-split (IFS) approach. Three blinded, independent readers measured CT attenuation values and evaluated image quality and degrees of artefacts using axial images, multi-planar reformations (MPRs) and maximal intensity projections (MIP) of the carotid arteries.
CT attenuation values of the internal carotid artery on images with metal artefacts were significantly higher in FBP (324 ± 104HU) datasets compared with those reconstructed with IFS (278 ± 114HU; P < 0.001) and with FBP on images without metal artefacts (293 ± 106HU; P = 0.006). Quality of IFS images was rated significantly higher on axial, MPR and MIP images (P < 0.05, each), and readers found significantly less artefacts impairing the diagnostic confidence of the internal carotid artery (P < 0.05, each).
The MAR algorithm with the IFS approach allowed for a significant reduction of artefacts from dental hardware in carotid CT angiography, hereby increasing image quality and improving the accuracy of CT attenuation measurements.
• CT angiography of the neck has proven value for evaluating carotid disease
• Neck CT angiography images are often degraded by artefacts from dental implants
• A metal artefact reduction algorithm with iterative reconstruction reduces artefacts significantly
• Visualisation of the internal carotid artery is improved
KeywordsMetal artefact reduction Computed tomography angiography Dental implants Internal carotid artery Carotid angiography
Metal artefact reduction
Iterative frequency split
Maximum intensity projection
Filtered back projection
Normalised metal artefact reduction
Two authors are employees of Siemens Healthcare. They did not have at any point of the study control over the data. The study data were controlled independently by the other authors.
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