title: Dual energy CT angiography: pros and cons of dual-energy metal artifact reduction algorithm in patients after endovascular aortic repair.
abstract: To evaluate the value of metal artifact reduction (MAR) post-processing and iodine MD images in fast kV-switching dual-energy computed tomography (DECT) in patients after endovascular aortic repair (EVAR).
  
  
  
  Twenty-four consecutive EVAR patients (age 76 ± 9 years, 7/24 (29%) with coils, 9/24 (37.5%) with 10 endoleaks) who underwent DECT angiography were included in this HIPAA-compliant, IRB-approved retrospective study. Monochromatic reconstructions included 55, 60, 65, 70, and 75 keV with and without MAR and iodine MD images. Near field, far field, and vessel artifacts were assessed subjectively (1 = none; 5 = severe) and objectively by measuring noise and contrast-to-noise ratio. Visibility of endoleak was evaluated (1 = optimal; 5 = not visible).
  
  
  
  MAR objectively decreased artifacts from EVAR stents in the near field (60.7 ± 25.4 HU vs. 70.1 ± 34.2; p = .002) and subjectively increased near field (3.2 ± 0.9 vs. 2.8 ± 0.6; p < .001), far field (2.2 ± 0.6 vs. 1.6 ± 0.6; p < .001), and vessel (3.1 ± 1.1 vs. 2.5 ± 0.9; p < .001) artifacts. Near-field artifacts from coils were reduced by the MAR objectively (72.4 ± 24.8 vs. 182.7 ± 57.3 HU; p < .001) and subjectively (4.5 ± 0.5 vs. 4.9 ± 0.4; p = .02). CNR of standard reconstructions was optimal at 60 keV (38.3 ± 16.8). Reconstructions without MAR and iodine MD images provided improved endoleak visualization in 6/10 (60%) of cases (median 1 for both) compared to MAR (median 3) (p < 0.001). However, MAR improved visualization in 1/10 (10%) cases due to endoleak location adjacent to a coil.
  
  
  
  DECT with MAR reduced artifacts from coils and improved endoleak visualization in 1/10 (10%) cases due to location adjacent to a coil. However, MAR impaired endoleak visualization in 6/10 (60%) cases and should be reviewed combined with 60 keV standard reconstructions and iodine MD images.
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA, 02215, USA.
authors.forename: Johannes
authors.initials: J
authors.lastname: Boos
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA, 02215, USA.
authors.forename: Jieming
authors.initials: J
authors.lastname: Fang
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA, 02215, USA.
authors.forename: Benedikt H
authors.initials: BH
authors.lastname: Heidinger
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA, 02215, USA.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Raptopoulos
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA, 02215, USA. obrook@bidmc.harvard.edu.
authors.forename: Olga R
authors.initials: OR
authors.lastname: Brook
mesh_terms: D000368:Aged; D000465:Algorithms; D001018:Aortic Diseases / Q000000981:diagnostic imaging* / Q000601:surgery*; D016477:Artifacts; D001807:Blood Vessel Prosthesis; D000072226:Computed Tomography Angiography / Q000379:methods*; D003287:Contrast Media; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008670:Metals; D011857:Radiographic Image Interpretation, Computer-Assisted; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D012189:Retrospective Studies; D015607:Stents; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D008670:Metals; D007472:Iohexol
keywords: Computed tomography; Dual energy; Endovascular aortic repair; Metal artifact reduction