| PurposeTo investigate the image quality of low dose triple rule-out(TRO)computed tomography angiography(CTA)examination using 256 row CT scannerin patients with free heart rate(HR).Methods155 chest pain patients collected form our hospital were randomly divided into study group and control group.The study group including 85 patients were carried out TRO CTAat 100 kV,while the other 70 patients served as the control groupwere implementedTRO CTAat 120 kV.Basic information of all the patients including gender,age,height,weight,HR were recorded.All patients underwent 256 rowRevolution CTscanner using a two-step protocol consisting of a spiral pulmonary artery examinationfollowed by a non-spiral coronary&thoracic aorta acquisition.The post-processingwere carried out at3-dimensional Advantage Workstation 461.Quantitative image quality was assessed as vascular CTattenuation value in the ascending aorta(AA),pulmonary trunk(PT)and right coronary artery(RCA).Signal-to-noiseratio(SNR)and contrast-to-noise ratio(CNR)inAA,PT,RCA were calculated.Subjective score ofAA,PT,RCA were assessed by two radiologists who had worked for more than 5 years.If the opinions were inconsistent,an agreement was reached through consultation.Moreover,patients ofthe study group were divided into group A(low heart rate group,n=30,HR?70beats/min),group B(medium heart rate group,n=30,70 beats/min <HR<85 beats/min),groupC(high heart rate group,HR?85 beats/min)according to HR.The SNR and CNR in AA,PA,RCA and subjective score of RCA was calculated todisscuss image quality ofpatients indifferent HR groups.ResultsThere was no statisticalsignificance in gender,age,and body mass index(BMI)between the study group and the control group.The SNR {PT 20.4 ± 4.7 vs 21.2 ± 5.4,AA 13.8(5.1)vs 13.2 ± 2.4,RCA 13.5(5.0)vs 14.0(4.0),p> 0.05},CNR {PT20.3(7.0)vs 23.1 ± 7.1,AA 16.1(7.8)vs 15.5(4.7),RCA16.1(7.3)vs 17.2(5.6),p > 0.05} and subjectivescore {PT 4.78±0.42 vs 4.84±0.37,Thoracic artery2.75±0.44 vs 2.80±0.40,RCA 1.69±0.67 vs 1.65±0.70,p>0.05}ofstudy and control group have nostatisticalsignificance,but the radiation dose of study group was significantly lower than the control group {4.7(2.0)vs 6.3.(1.7),p < 0.001}.The SNR{PT 20.0(6.6)vs 19.9 ± 3.9 vs 19.3 ± 5.2,AA15.2(4.8)vs 13.8 ± 3.7 vs 13.4(6.1),RCA 12.4(6.9)vs 13.5 ± 3.9 vs 13.6(3.5),p> 0.05} and CNR{PT 22.0(6.7)vs 21.6 ± 6.1 vs 19.1(5.8),AA18.2 ± 3.7 vs 14.6(8.0)vs 14.2(8.3),RCA 17.1(5.2)vs 14.8 ± 4.9 vs 17.1(8.6),p > 0.05}and subjective score of RCA(1.61 ± 0.65 vs 1.72 ± 0.68 vs1.72±0.65,p=0.052)have no statisticalsignificancein group A,B and Cwith different HR.Conclusion TRO CTA examination using 256 row CT scanner in chest pain patients with free HR was feasible atlow dose,which can effectively guarantee the image quality even in patients with high HR. |
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