OBJECTIVETo investigate the image quality and radiation dose of dual-energy (DE) computed tomographic angiography (CTA) of head and neck.

METHODSWe retrospectively analyzed two groups of patients (both n=30) undergoing 64-slice spiral CTA of cervical and cranial regions with different scan protocols. The DE group was obtained with 140/80 kVp, 64/272 mAs, 0.6 pitch, 80 ml of contrast medium, and caudal-cranial scan orientation. The single-energy (SE) group was obtained with 120 kVp, 220 mAs, 1.2 pitch, 60 ml of contrast medium and cranial-caudal scan orientation. The image quality and radiation dose were compared. The attenuation values and noises were measured on transverse images at 4 different vessels (the distal part of common carotid artery and adjacent vein in same axial image; the M1 segment of middle cerebral artery and sigmoid sinus or confluence of sinus in same image) and two muscles: erector spinae presenting average soft tissue enhancement and supraspinatus muscle presenting regions of great artifact.

RESULTSIn cranial region the arterial enhancement and venous contamination were similar (P=0.1427,P=0.1116) . In cervical region the arterial enhancement was similar (P=0.9414) . DE group had significantly greater venous contamination (P<0.0001) , while the mean attenuation value of common carotid artery was still 127 Hu higher than that of jugular vein. No matter artifact of soft tissue was obvious or not, the noise of DE group was significantly less than that of SE group (both P<0.0001) , and the soft tissue enhancement was similar (P=0.0760,P=0.0793) . The radiation dose required for bone-subtraction angiography was significantly less in DE group than in SE group (P<0.0001) .

CONCLUSIONSDE group has comparable image quality to SE group and less scan dose for bone-subtraction. DE-CTA has great potential in clinical application. "