title: Aortoiliac and lower extremity arteries assessed with 16-detector row CT angiography: prospective comparison with digital subtraction angiography.
abstract: OBJECTIVE
  To prospectively compare the accuracy of 16-detector row computed tomographic (CT) angiography with conventional digital subtraction angiography (DSA) as the reference standard in the assessment of aortoiliac and lower extremity arteries in patients with peripheral arterial disease.
  
  
  METHODS
  This study was approved by the institutional review board, and informed consent was obtained. A total of 39 consecutive patients (27 men [mean age, 66 years] and 12 women [mean age, 64 years]) with peripheral arterial disease underwent both conventional DSA and 16-detector row CT angiography. For data analysis, the arterial vascular system was divided into 35 segments. A total of 1365 arterial segments were analyzed for arterial stenosis by two independent blinded readers using a four-point grading system (grade 1, <10% luminal narrowing; grade 2, 10%-49% luminal narrowing; grade 3, 50%-99% luminal narrowing; grade 4, occlusion). Interobserver agreements were calculated by using kappa statistics. A third independent blinded reader assessed possible reasons for disagreements between 16-detector row CT angiographic findings and conventional DSA findings. Effective radiation dose was calculated for both imaging modalities.
  
  
  RESULTS
  Sixteen-detector row CT angiographic and conventional DSA findings were diagnostic in all vascular segments. Compared with conventional DSA, the sensitivity and specificity of 16-detector row CT angiography with regard to detection of hemodynamically significant stenosis in all 35 arterial segments were 96% and 97%, respectively, for both readers. Readers 1 and 2 overestimated arterial stenosis in 42 (3%) and 34 (2%) arterial segments, respectively, and underestimated arterial stenosis in 13 (1%) and 10 (1%) arterial segments, respectively. Interobserver agreement was excellent (kappa = 0.84-1.00). Presence of anteroposteriorly located luminal narrowing and extensive vascular wall calcification were considered main reasons for disagreements between imaging modalities. Effective radiation dose was lower for 16-detector row CT angiography (1.6-3.9 mSv) than for conventional DSA (6.4-16.0 mSv).
  
  
  CONCLUSIONS
  Sixteen-detector row CT angiography is an accurate and reliable noninvasive alternative to conventional DSA in the assessment of aortoiliac and lower extremity arteries in patients with peripheral arterial disease.
authors.affiliation: Institute of Diagnostic Radiology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland. juergen.willmann@usz.ch
authors.forename: Jürgen K
authors.initials: JK
authors.lastname: Willmann
authors.forename: Bernhard
authors.initials: B
authors.lastname: Baumert
authors.forename: Thomas
authors.initials: T
authors.lastname: Schertler
authors.forename: Simon
authors.initials: S
authors.lastname: Wildermuth
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfammatter
authors.forename: Francis R
authors.initials: FR
authors.lastname: Verdun
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Seifert
authors.forename: Borut
authors.initials: B
authors.lastname: Marincek
authors.forename: Thomas
authors.initials: T
authors.lastname: Böhm
mesh_terms: D000328:Adult; D000368:Aged; D000792:Angiography / Q000379:methods*; D015901:Angiography, Digital Subtraction; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed