Cerebral Artery Evaluation Of Dual Energy CT Angiography With Dual Source CT

PURPOSEConventional CT angiography (CTA) was time consuming, user-dependent with poor image quality in skull base region. This study was to assess feasibility of a new method, dual energy CTA in depicting cerebral artery, radiation dose, image post-processing time and reading time.METHODSPhantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation respectively. Dual energy CTA was done with dual source CT on 36 patients who were suspected cerebral vascular disease.3 series axial images in 0.75mm thick,0.4mm increment were acquired, which were named with 80Kv,140Kv and merged images.80Kv,140Kv images were transferred into dual energy software, and maximum intensity projection (MIP) image was generated quickly by dual energy bone remove (DEBR group); Merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove (CoBR group). Post processing time and image reading time were compared. MIP image quality was assessed in consensus by two radiologists in a blinded fashion with a four-point Likert-type scale. Images quality of two groups were compared, mainly focus on skull base segments of internal carotid artery and bone subtraction. ANOVA and S-N-K test was applied for radiation dose comparison; Student t test and Wilcoxon rank sum test were applied for differences between score data for significance. Cohen's kapaa was used for interobserver agreement.RESULTSRadiation dose of phantom scan demonstrated that of dual energy CTA was between digital bone subtraction (Neuro-DSA) and conventional CTA. The post processing time, reading time was much shorter in DEBR than CoBR, image quality in skull base was much higher in DEBR than CoBR (P<0.001).No significant difference for suprasellar vessels between two groups (P>0.5). Interobserver agreement for all vessel segments was excellent (kappa= 0.97).CONCLUSIONSDual energy CTA was a reliable, new modality for depicting cerebral artery, overcome the limitation of conventional CTA in skull base region. It can save much time in post processing and image reading than conventional CTA, and its radiation dose is less than Neuro-DSA CTA.