Cerebral artery evaluation of dual energy CT angiography with dual source CT / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Conventional computed tomography angiography (CTA) is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.</p><p><b>METHODS</b>Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV 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 reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student's t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen's kappa was used for interobserver agreement.</p><p><b>RESULTS</b>Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR (P < 0.01). There was no significant difference for suprasellar vessels between two groups (P > 0.5). Interobserver agreement for all vessel segments was excellent (kappa = 0.97).</p><p><b>CONCLUSIONS</b>Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.</p>

Dual-sided reading versus single-sided reading:comparison of image quality and radiation dose between the two computed radiography systems / 中华放射学杂志

Objective To assess and compare the difference in image quality and exposure dose between single-sided reading image plate(IP)and dual-sided reading IP.Methods A contrast-detail phantom CDRAD 2.0 was exposed by single-sided and dual-sided reading IP with different mAs sets.The entrance surface doses were recorded for all images.Images were then presented to two radiologists on a high resolution monitor of diagnosis workstation.The image quality figure(IQF)was measured for each image. Statistical analysis was performed using Spearman's correlation test and Wilcoxon signed-rank test to compare the difference in image quality and exposure dose between single-sided IP and dual-sided reading IP. Results With different tube current dosage of 5.6,12.0,20.0,25.0,and 40.0 mAs,IQF values of single-sided reading IP were 47.95,37.68,34.31,28.61,and 24.65,respectively,while those of dual- sided reading IP were 38.83,29.81,29.65,25.16,and 21.43,respectively.The IQF difference between them showed statistical significance(P