Head and neck angiography at 70kVp with a third-generation dual-source CT system in patients: comparison with 100kVp.

Abstract

This study was conducted in order to evaluate the image quality of 70kVp and 25mL contrast medium (CM) volume for head and neck computed tomographic angiography (CTA) and assess the diagnostic accuracy for arterial stenosis. Fifty patients were prospectively divided into two groups randomly: group A (n=25), 70kVp with 25mL CM, and group B (n=25), 100kVp with 40mL CM. CT attenuation values, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of the shoulder, neck, and cerebral arteries were measured for objective image quality. Subjective image quality of the shoulder and cerebral arteries was also evaluated. For patients undergoing digital subtracted angiography (DSA), diagnostic accuracy of CTA was assessed with DSA as reference standard. The SNRs of the shoulder, neck, and cerebral arteries in group A were higher than those in group B (P<0.05). The CNRs of the shoulder and neck arteries in group A were higher than those in group B (P<0.05). There was no significant difference in subjective image quality of arteries between group A and group B (P>0.05). The accuracy was noted as 94.0% (156/166) in group A and 97.1% (134/138) in group B for ≥ 50% stenosis. The accuracy of intracranial arterial stenosis was lower than that of extracranial arterial stenosis in group A. The radiation dose of group A was significantly decreased by 56% than that of group B. Head and neck CTA at 70kVp using 25mL CM can obtain diagnostic image quality with lower radiation dose while maintaining high accuracy in detecting the arterial stenosis compared with the 100-kVp and 40-mL CM.