Inter-observer variation. An alternative method of assessing the role of ultrasonic imaging in clinical decision-making in lower limb arterial disease.
BACKGROUND
The aim of the study is to determine the role of duplex scanning in deciding on the final treatment for patients with lower limb arterial disease compared to intra-arterial digital subtraction arteriography (IA DSA).


METHODS
Eighty-two patients (55 males, 27 females, mean age 68 years) with lower limb arterial disease had both duplex and arteriography performed. The findings of both modalities were reported by sonographer and radiologist in 164 anonymous reports. Five vascular surgeons (consultant grade) were asked to plan their treatment on the data provided in these reports. For the purposes of statistical analysis, the actual treatment the patient received was used as the reference standard. Both reports and treatment decisions were coded (double blinded).


RESULTS
The overall accuracy of duplex scanning to assess arterial disease of the lower limbs showed a sensitivity of 92%, and specificity of 99%. The accuracy of the decisions based on duplex was 84% and kappa with k of 0.62 (95% CI+0.14) compared to the reference standard, while the accuracy of the decision based on arteriography was 85% and kappa 0.63 (95% CI+0.14). The accuracy of decisions based on duplex compared to those based on arteriography (arteriography used as reference standard) was 91% and a kappa of 0.77 (95% CI+0.14).


CONCLUSIONS
Duplex scanning is an accurate diagnostic modality, and clinical decisions can be safely based on its findings.
Aly
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Department of Surgery, University College London Medical School, London, Great Britain.
Shoab
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Bishop
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D000368:Aged; D015901:Angiography, Digital Subtraction; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging*; D003658:Decision Making, Computer-Assisted; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D015588:Observer Variation; D012680:Sensitivity and Specificity; D018616:Ultrasonography, Doppler, Duplex