Optimization of scanning protocol in low-dose one-stop CT perfusion imaging combined with CTA of whole brain / 中国医学影像技术

ABSTRACT

Objective To optimize protocol in one-stop whole brain CT perfusion imaging (CTP) combined with CTA.Methods Totally 45 subjects underwent one-stop whole brain CTP combined with CTA with three different scanning protocols and 22 phases.CTA images were reconstructed from CTP original data at the tenth phase,the protocols of three scanning groups were as followsGroup A using automatic tube current modulation technique (ATCM) with low noise index (NI;NI=2),group B with fixed tube current (325 mA) and group C using ATCM with slightly low NI (NI=2.5),and the other phases of three groups were performed with ATCM and NI=8.Tube voltage of all three scanning protocols was 100 kV.The radiation dose and related parameters were recorded.Objective parameters including image noise (SD),SNR,CNR and perfusion parameters in different parts of the brain parenchyma and subjective scores of CTA,CTP image quality were compared among three groups.Results There was significant difference of effective dose (ED) among three groups (P＜0.05).ED of group A was higher than that of group B and C (P=0.043,0.001).No difference was found in CTA image noise,SNR,CNR nor subjective scores among three groups (P=0.218,0.545,0.575,0.900),neither of CTP images among three groups (P＞ 0.05).Conclusion Using ATCM and increasing NI appropriately may reduce radiation dose in one-stop CTP combined with CTA.