The Study of CT Angiography of Cervical Arteries Scanning at Low-dose with Multi-slice Spiral CT

Objective To study the rationality and possibility of multi-slice spiral CT in the examination of the cervical arteries CT angiography at low-dose.Materials and Methods 60 cases by routine cervical arteries CT angiography were randomly divided into three groups,group A,group B and group C.With the others scanning parameters kept unchanged,the patients in group A were scaned with a routine dose of 250 mAs,the others in group B and C were scaned with a low dose of 150 mAs and 100 mAs.Anatomic structures and lesions showed on images were chosen to evaluate and compare the difference in images quality of three groups.Results CT dose index(CTDI) was reduced from 16.7mGy to 10.0 mGy(decreased 40.1%) and 6.7 mGy(decreased 59.8%) when mAs decreased from 250 mAs to 150 mAs and 100 mAs.Dose lenth product(DLP) was reduced from(564.6±32.5)mGy to(336.2±24.5)mGy(decreased 40.5%) and(204.3±33.7)mGy(decreased 63.8%) when mAs decreased from 250 mAs to 150 mAs and 100 mAs.There was significant difference between group A and B(P0.01),while obvious difference could not be found in the quality of images obtained from group A and B(P0.05).Conclusion It is a feasible CT angiography scanning method to decrease the radiation dose by decreasing mAs appropriately,150mAs was chosen.