Diagnostic performance and radiation dose of lower extremity CT angiography using a 128-slice dual source CT at 80kVp and high pitch

Background Multi-detector computed tomography (MDCT) angiography is now used for the diagnosing patients with peripheral arterial disease. The dose of radiation is related to variable factors, such as tube current, tube voltage, and helical pitch. Purpose To assess the diagnostic performance and radiation dose of lower extremity CT angiography (CTA) using a 128-slice dual source CT at 80kVp and high pitch in patients with critical limb ischemia (CLI). Material and Methods Twenty-eight patients (mean, 64.1 years; range, 39-80 years) with CLI were enrolled in this retrospective study and underwent CTA using a 128-slice dual source CT at 80kVp and high pitch and subsequent intra-arterial digital subtraction angiography (DSA), which was used as a reference standard for assessing diagnostic performance. Results For arterial segments with significant disease (>50% stenosis), overall sensitivity, specificity, and accuracy of lower extremity CTA were 94.8% (95% CI, 91.7-98.0%), 91.5% (95% CI, 87.7-95.2%), and 93.1% (95% CI, 90.6-95.6%), respectively, and its positive and negative predictive values were 91.0% (95% CI, 87.1-95.0%), and 95.1% (95% CI, 92.1-98.1%), respectively. Mean radiation dose delivered to lower extremities was 266.6 mGy.cm. Conclusion Lower extremity CTA using a 128-slice dual source CT at 80kVp and high pitch was found to have good diagnostic performance for the assessment of patients with CLI using an extremely low radiation dose.