Do the cardiovascular risk profile and the degree of arterial wall calcification influence the performance of MDCT angiography of lower extremity arteries?
OBJECTIVE
To retrospectively assess the influence of arterial wall calcifications on the accuracy of run-off computed tomographic angiography (CTA) and to analyse whether cardiovascular risk factors are predictors of compromising calcifications.


METHODS
In 200 consecutive patients who underwent run-off CTA, calcifications were assessed in pelvic, thigh and calf arteries using a four-point scale. Fifty-nine patients with digital subtraction angiography (DSA) were assessed by both techniques to estimate a threshold of compromising calcifications, defined as a decrease of sensitivity, specificity, PPV or NPV below the lower 95% confidence interval of overall results. Regression analysis was performed to investigate a potential relationship between compromising calcifications and presence of cardiovascular risk factors, advanced patient age and severe peripheral arterial disease (PAD).


RESULTS
The highest Ca(++)-score was chosen as the cut-off for the regression analysis, as a relevant decrease of specificity (0.91; overall: 0.95) above the knee and of sensitivity (0.66; overall: 0.83), specificity (0.65; overall: 0.93), positive predictive value (PPV) and negative predictive value (NPV) below the knee was observed. In the pelvic and thigh arteries, severe PAD (Fontaine Stage >or=III) showed the highest odds ratio for compromising calcifications (2.9), followed by diabetes mellitus (2.4), renal failure (2.1) and smoking (1.7). In the calf, renal failure (12.2) and diabetes mellitus (3.3) were the strongest predictors.


CONCLUSIONS
Patients with diabetes and renal failure should be considered as candidates for alternative vessel imaging in order to avoid inconclusive examination results.
Department of Radiology and Nuclear Medicine, Charité-University Medicine, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany. Bernhard.Meyer@charite.de
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Meyer
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Werncke
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Foert
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Kruschewski
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Hopfenmüller
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Ribbe
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KJ
Wolf
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Albrecht
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D035002:Lower Extremity / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods