Application Of 320-row CT Wide Volume Scanning Mode Combined With ECG Gating Technique In Computed Tomography Pulmonary Artery

Objective:To explore the clinical application value of 320 row CT wide volume scanning mode combined with ECG gating technology in pulmonary artery CTA.Methods:90 patients with suspected acute PE were scanned with CTPA and divided into 3 groups according to random number table.Group A used non ECG gated spiral scan（30 cases）;group Bused retrospective ECG gated spiral scan（30 cases）;group C used retrospective ECG gated wide volume scan（30 cases）.The post-processing images were scored subjectively by two senior radiologists.Objective evaluation:CT value,signal-to-noise ratio（SNR）and contrast to noise ratio（CNR）of main pulmonary artery,bilateral pulmonary artery and its 3-4 branches were measured three times,and the average value was compared.The basic clinical information,CTDIvol,DLP and ED were recorded.Result:1.All 90 patients completed CT pulmonary angiography successfully.There was no significant difference in general information（age,body mass index and gender）among the three groups（P>0.05）.2.Subjective score:The score of group A was（3.8±0.9）,group B was（4.4±0.6）,and group C was（4.5±0.7）.The subjective score of group B and group C was higher than that of group A（P<0.01）.The score consistency of the three groups was excellent（kappa value>0.75,P<0.05）.There were 14 cases in group A,6 cases in group B and 2cases in group C with heart beating artifacts.The number of artifacts in group A was the most,while that in group C was the least.The image display was the best.The vessels above grade 7 could be observed with smooth and sharp edges,especially the right middle lobe pulmonary artery and the left upper lobe pulmonary artery.3.Objective evaluation:The CT value,SNR and CNR of all branches in the three groups were statistically significant（P<0.05）.A.There were significant differences in SNR and CNR of main pulmonary artery,right pulmonary artery and its branches,left pulmonary artery and its branches between group B and groups A and C（P<0.05）.Among them,the CT value of left upper lobe pulmonary artery caused by pericardial artifacts was compared among the three groups:the largest（575.5±97.2）Hu in group B and the smallest（484.1±131.4）Hu in group A（P<0.05）;the largest（39.0±9.5）Hu in group B and the smallest（28.1±13.4）Hu in group A in SNR comparison（P<0.05）;the largest（26.0±13.1）Hu in group B and the smallest（36.2±9.0）Hu in group A in CNR comparison（P<0.05）;there was no difference between group B and group C（P>0.05）The CT value of right middle lobe pulmonary artery in group B was the largest（632.7±264.7）Hu and that in group A was the smallest（474.0±126.1）Hu（P<0.05）;the SNR value in group B was the largest（37.8±14.1）Hu and that in group A was the smallest（27.6±14.1）Hu（P<0.05）;the CNR value in group B was the largest（35.4±13.4）Hu and that in group A was the smallest（25.4±13.7）Hu（P<0.05）;there was no difference between group B and group C（P>0.05）.4.Radiation dose:There were significant differences in radiation dose among the three groups（P<0.001）.CTDIvol and DLP were（9.1±1.5）m Gy,（19.7±6.3）m Gy,（13.6±3.7）m Gy and（241.7±42.4）m Gy,respectively m Gy.cm^-1、（509.1±156.1）m Gy.cm^-1、（362.2±145.1）m Gy.cm^-1.Ed was（3.3±1.1）m Sv,（7.3±2.1）m Sv,（5.2±2.0）m Sv,which was the lowest in group A and the highest in group B.the three radiation dose indexes（CTDIvol、DLP、ED）in group C were 31%,29%and 30%lower than those in group B,respectively.Conclusion:The application of 320 row wide volume scanning mode combined with retrospective ECG gating technology in CTPA scanning,compared with the conventional retrospective ECG gated spiral scanning technology,it can effectively reduce the radiation d ose,significantly improve the pericardial pulsation artifacts,and imp rove the image quality.