title: Metal artefact reduction from dental hardware in carotid CT angiography using iterative reconstructions.
abstract: OBJECTIVE
  To determine the value of a metal artefact reduction (MAR) algorithm with iterative reconstructions for dental hardware in carotid CT angiography.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  • 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.
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
authors.forename: Fabian
authors.initials: F
authors.lastname: Morsbach
authors.forename: Moritz
authors.initials: M
authors.lastname: Wurnig
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Kunz
authors.forename: Andreas
authors.initials: A
authors.lastname: Krauss
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Spyros S
authors.initials: SS
authors.lastname: Kollias
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
mesh_terms: D000368:Aged; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D016477:Artifacts; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging*; D015921:Dental Implants; D005260:Female; D006801:Humans; D008297:Male; D008670:Metals; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D015921:Dental Implants; D008670:Metals