Feasibility of low dose Flash spiral scan mode of dual-source CT in cerebral double phase subtraction angiography / 实用放射学杂志

ABSTRACT

Objective To assess the feasibility of double phase subtraction angiography with second generation (128-slice )dual-source CT in low dose Flash spiral scan mode for the evaluation of cerebral vessel,compared with dual-energy subtraction angiogra-phy.Methods 60 patients underwent double phrase CT angiography were divided into group A (n = 30,with Flash spiral scan mode),group B(n=30,with dual-energy scan mode).The signal-to-noise ratio(SNR),the contrast-to-noise ratio(CNR)and the av-erage radiation of double phrase subtraction images were measured in two groups,respectively.The double phase subtraction images quality were graded by 2 independent readers on a 5-point scale(5=excellent)in double-blind,according to various degrees of the re-sidual bones,the vessel displayed and luminal integrity,respectively.Differences between two groups were analyzed by Mann-whit-ney test and t test.Results The double phrase image SNR showed no difference to both two groups(P >0.05).The image CNR of arterial and venous phase in group A were higher than that of group B(40.89±8.89 and 40.27 ±9.90 in group A vs 35.28 ±8.43 and 34.89±8.66 in group B;P 0.05).The vessel image scores of arterial phase were higher in group A than that of group B(4.93±0.25 vs 3.87±0.97;P <0.05).Some internal carotid in the base of skull has not good luminal integrity in group B.The mean dose length product (DLP)in group A was lower than that of group B,with a 39 percent reduction[(226±5.69 )mGy/cm vs (368 ± 21.35 )mGy/cm,P < 0.05 ].Conclusion With the roughly similar image quality to dual-energy double phase subtraction angiography,the cerebral vessels can be assessed using dual-source CT subtraction angiography in Flash spiral scan mode and a lower radiation dose.