A comparative observation of cerebral CT angiography with time and dual-energy subtraction / 中国医学影像技术

ABSTRACT

Objective To compare the image quality and scanning dose of time-subtraction and dual-energy-subtraction cerebral CT angiography, and to assess clinical application value of both methods. Methods Plain and enhanced scanning were performed on 60 patients suspected cerebral vessel diseases with dual-source CT. Dual-energy mode with tube voltages of 140 and 80 kV was used in enhanced scanning, and data of two different energy were collected in one scanning. ①Traditional removed-bone digital subtraction (time-subtraction) with plain and 80 kV enhanced scanning data were obtained. Volume render (VR) and maximum intensity projection (MIP) reconstruction were finished; ②Direct removed-bone digital subtraction (dual-energy subtraction) with 80 kV and 140 kV enhanced scanning data were obtained. VR and MIP reconstruction were finished. The image quality of VR and MIP was divided into 4 grades, and were compared as well as average effective radiological dose. All the diseases were confirmed with surgery or DSA. Average effective radiological dose was compared with time-subtraction and dual-energy subtraction. Results Internal carotid artery trunk and branch and Willis circles were displayed clearly with two methods in 60 cases. No significant difference was found (P>0.05) between total quality score of the two methods. The size, shape, neck and axis point of aneurysm in 24 cases were clearly displayed, so as the shape and extent of abnormal vessel bolus in 4 cases, while arteries and veins were also clear in artery-vein malformation; ③The average radiological dose was (26.60±0.50)mSv in time-subtraction and (22.40±0.50) mSv in dual-energy subtraction. Conclusion The normal, abnormal vessels and diseases can be clearly displayed at time-subtraction and dual-energy subtraction CTA. The effect of dual-energy-subtraction is better than that of time-subtraction CTA in no-cooperation patients, and the radiological dose is lower in dual-energy CTA.