Diagnostic efficiency of low-dose CT angiography compared with conventional angiography in peripheral arterial occlusions.

OBJECTIVE: The purpose of this study was to assess the diagnostic efficiency and radiation dose of peripheral arterial CT angiography (CTA) performed at a low tube voltage of 70 kV in comparison with conventional angiography. SUBJECTS AND METHODS: Thirty consecutive patients (body mass index ≤ 25 kg/m(2)) with known or suspected peripheral arterial occlusion diseases underwent both CTA at a low tube voltage of 70 kV and conventional angiography. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of peripheral arterial CTA were evaluated. The radiation dose was recorded.
RESULTS: Diagnostic CTA images were obtained in all patients. CTA allowed accurate identification, characterization, and measurement of all peripheral arterial occlusive diseases. In conventional angiography, 360 diseased segments were found among the 810 segments evaluated. The sensitivity, specificity, PPV, NPV, and accuracy of CTA were 100% (95% CI, 98.81-100%), 93.5% (90.96-95.36%), 90.86% (87.38-93.45%), 100% (99.17-100%), and 96.05% (94.48-97.19%), respectively, with a kappa value of 0.92 (excellent agreement). The mean CT dose index was 3.71 ± 0.8 mGy, and the dose-length product was 446.6 ± 35.7 mGy × cm. The effective dose was 1.94 ± 0.21 mSv for CTA and 4.41 ± 0.64 mSv for conventional angiography.
CONCLUSION: CTA of peripheral arteries with a low tube voltage of 70 kV provides reliable information and serves as a rapidly performed and easily available "one-stop-shop" imaging modality in the diagnosis of peripheral arterial occlusion diseases.