title: Grading of carotid artery stenosis in the presence of extensive calcifications: dual-energy CT angiography in comparison with contrast-enhanced MR angiography.
abstract: OBJECTIVE
  We investigated the agreement of dual-energy computed tomography angiography (DE-CTA) and contrast-enhanced magnetic resonance angiography (CE-MRA)in the quantitative measurement of stenoses of the internal carotid artery in comparison with digital subtraction angiography (DSA).
  
  
  METHODS
  A total of 21 patients with stenoses of the external carotid artery were investigated with a DE-CTA and CE-MRA before undergoing carotid angioplasty. The grade of the stenoses was assessed in axial multiplanar reformations (MPR) before and multi-intensity projections (MIP) after plaque subtraction (PS) and compared with results from CE-MRA and DSA according to the North American Symptomatic Carotid Endarterectomy Trial.
  
  
  RESULTS
  Average grades of stenoses were 80.7 ± 16.1 % (DSA), 81.4 ± 15.3 % (MRA), 80.0 ± 16.7 % (DE-CTA-MPR), and 85.2 ± 14.7 % (DE-CTA-PS-MIP). Of 21 stenoses, 6 were filiform (stenosis grade, 99 %) in the DSA examination. Five of these cases were identified as pseudo-occlusions in MRA, while four were considered as occlusions in DE-CTA-PS-MIP. Another four cases were identified as pseudo-occlusion in DE-CTA-PS-MIP, which were identified as 90 % stenosis in the DSA examination.
  
  
  CONCLUSIONS
  In comparison with the gold standard DSA, DE-CTA-MPR had a slightly better agreement in measuring the degree of stenosis of the internal carotid arteries than CE-MRA. In DE-CTA-PS-MIP images, a systematic overestimation has to be taken into account due to partial extinction of the lumen by the PS algorithm. Nevertheless, DE-CTA should be preferred in imaging patients with carotid artery stenosis in the presence of extensive calcifications.
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany, andreas.korn@med.uni-tuebingen.de.
authors.forename: A
authors.initials: A
authors.lastname: Korn
authors.forename: B
authors.initials: B
authors.lastname: Bender
authors.forename: H
authors.initials: H
authors.lastname: Brodoefel
authors.forename: T-K
authors.initials: TK
authors.lastname: Hauser
authors.forename: S
authors.initials: S
authors.lastname: Danz
authors.forename: U
authors.initials: U
authors.lastname: Ernemann
authors.forename: C
authors.initials: C
authors.lastname: Thomas
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002114:Calcinosis / Q000150:complications / Q000175:diagnosis*; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D008875:Middle Aged; D009942:Organometallic Compounds; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine