title: Interobserver agreement for the interpretation of contrast-enhanced 3D MR angiography and MDCT angiography in peripheral arterial disease.
abstract: OBJECTIVE
  The objective of our study was to compare interobserver agreement for interpretations of contrast-enhanced 3D MR angiography and MDCT angiography in patients with peripheral arterial disease.
  
  
  METHODS
  Of 226 eligible patients, 69 were excluded. The remaining 157 consecutive patients were prospectively randomized to either MR angiography (n = 78) or MDCT angiography (n = 79). Two observers independently evaluated for arterial stenosis or occlusion on MR angiography (2,157 segments) and MDCT angiography (2,419 segments) using a 5-point ordinal scale. Vessel wall calcifications were noted. Interobserver agreement for each technique was evaluated with a weighted kappa (kappa(w)) statistic.
  
  
  RESULTS
  Although interobserver agreement for both was excellent, the interobserver agreement for MR angiography (kappa(w) = 0.90; 95% confidence interval [CI], 0.89-0.92) was higher than that for MDCT angiography (kappa(w) = 0.85; 95% CI, 0.83-0.86) for reporting the degree of arterial stenosis or occlusion in all segments. For the different anatomic locations, the interobserver agreement for MR angiography versus MDCT angiography was as follows: aortoiliac (kappa(w) =0.91 vs 0.84, respectively), femoropopliteal (kappa(w) = 0.91 vs 0.87), and crural (kappa(w) = 0.90 vs 0.83) segments. The interobserver agreement of MDCT angiography significantly decreased in the presence of calcifications but was still good for all anatomic locations. The lowest agreement was found for crural segments in the presence of calcifications (kappa(w) = 0.67). With MR angiography, there were 12 times more nondiagnostic segments than with MDCT angiography (81 vs 7, respectively).
  
  
  CONCLUSIONS
  Interpretations of MR angiography and MDCT angiography for peripheral arterial disease have an excellent interobserver agreement. MR angiography has a higher interobserver agreement than MDCT angiography, and the presence of calcified segments significantly decreases interobserver agreement for MDCT angiography.
authors.affiliation: Department of Radiology, Erasmus Medical Center, Dr. Molewaterplein 50, Rm. Ee 2118, 3015 GE Rotterdam, The Netherlands. r.ouwendijk@erasmusmc.nl
authors.forename: Rody
authors.initials: R
authors.lastname: Ouwendijk
authors.forename: Marc C J M
authors.initials: MC
authors.lastname: Kock
authors.forename: Karen
authors.initials: K
authors.lastname: Visser
authors.forename: Peter M T
authors.initials: PM
authors.lastname: Pattynama
authors.forename: Michiel W
authors.initials: MW
authors.lastname: de Haan
authors.forename: Myriam G M
authors.initials: MG
authors.lastname: Hunink
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008875:Middle Aged; D015588:Observer Variation; D016491:Peripheral Vascular Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA