title: Duplex scanning compared with intra-arterial angiography in diagnosing peripheral arterial disease: three analytical approaches.
abstract: BACKGROUND
  This study was undertaken to assess the reliability of duplex scanning, as compared with digital subtraction angiography, in diagnosing peripheral arterial disease of the lower limbs.
  
  
  METHODS
  60 legs were studied. Each leg was divided in 5 arterial segments, from aortoiliac to popliteal. Duplex scanning and digital subtraction angiography were performed. The disease in each segment was assessed as significant or insignificant or classified into five categories concerning the grade of stenosis (patent vessel or no diameter reduction, mild stenosis, i.e. 1-19% diameter reduction, moderate and severe stenosis, i.e. 20-49% and 50-99% diameter reduction, respectively, and occluded vessel). Three statistical approaches were applied: calculating sensitivity and specificity, Kappa statistics, and weighted Kappa value. Median grades of arterial stenosis across different segments, according to angiography measurements, were also calculated.
  
  
  RESULTS
  The duplex sensitivity in detecting significant lesions ranged from 0.46 to 0.88. The Kappa values of agreement between duplex and angiography ranged from 0.35 to 0.64. Weighted Kappa values ranged from 0.45 to 0.72. Median grades of arterial lesions ranged from 2 (interquartile range 1-2) to 4 (3-4) and differed significantly (Kruskal-Wallis H test, p < 0.001).
  
  
  CONCLUSIONS
  The sensitivities and specificities suggested various duplex reliabilities in detecting significant arterial disease across different lower limbs segments. The Kappa values, in general, testified duplex's insufficient accuracy in grading the severity of stenosis. However, weighted Kappa values confirmed duplex's better ability to approximate the grade of stenosis. The arterial segments themselves were unevenly affected with the peripheral arterial disease.
authors.affiliation: Department of Radiology, Holy Ghost (Sveti Duh) General Hospital, Zagreb, Croatia. anton.krnic@zg.t-com.hr
authors.forename: A
authors.initials: A
authors.lastname: Krnic
authors.forename: N
authors.initials: N
authors.lastname: Vucic
authors.forename: Z
authors.initials: Z
authors.lastname: Sucic
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007866:Leg / Q000098:blood supply*; D008297:Male; D015588:Observer Variation; D016491:Peripheral Vascular Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011150:Popliteal Artery / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018615:Ultrasonography, Doppler, Color