Individual Management Of Heart Rate In64Row Coronary CT Angiography: Clinical Application Study

Objective: To analyze the contribution of individual management of heart rate in64Row Coronary CT Angiography, and develop one guidance to individual radiation doseadministration in coronary CT angiography.Materials and Methods:909patients were analyzed retrospectively. There were twophases, the first phase included360patient, the second phase included549patients, everyphase divided in5groups on base of the basic heart rate of patients. And every phase haddifferent management of Heart Rate.⑴. to compare basic HR、basic HRV、dosage ofβ-blocker、the time to achieve stable heart rate、pretest HR、pretest HRV、CCTA HR、CCTA HRV of patients at different groups, and calculate the decrease of pretest HR、pretest HRV, and analysis the correlation of pretest HR and CCTA HR in the two phases.⑵. to analysis the change tendency of HR、HRV in the second phase.⑶. to calculateaccuracy rating of pretest HR、pretest HRV in second phase.⑷. to calculate effectivedose(ED) with individual management of heart rate or not, and grade image quality at threedifferent scan mode.Results:⑴. There was no significant difference among basic HR、basic HRV inevery group (P>0.05).⑵. Dosage of β-blocker in second phase were larger than first phaseexcept <55bpm group (P<0.05).⑶. The mean time to achieve stable heart rate was5.8s,the minimum time was4s, the maximum time was9s.⑷. Pretest HR were lower thanbasic HR in≥55bpm groups of the first phase and all groups of second phase (P<0.05);pretest HR was decreased by12.4%in whole in first phase, and by15.1%in second phase.Pretest HRV were lower than basic HRV in≤84bpm groups of the first phase and allgroups of second phase (P<0.05); pretest HRV was decreased by30.1%in whole in first phase, and by52.1%in second phase.⑸. Correlation of pretest HR and CCTA HR：r=0.646(the first phase), r=0.574(the second phase).⑹. In second phase, HR stepped upin the stage of scout1and then descented, HRV stepped up in the stage of TEST BLOUS.⑺. In second phase, accuracy rating of pretest HR was84.0%(±5bpm), accuracy rating ofpretest HRV was96.9%(±5bpm).⑻. ED was decreased by22.5%with individualmanagement of heart rate theoretically.⑼. The image quality score of single-sector single-phase scan、single-sector half-phase scan was1.52±0.83、1.62±0.90respectively, there wasno significant difference (P>0.05), The image quality score of two-sector half-phase scanwas3.75±0.89, higher than single-sector scan (P<0.05).Conclusion: Individual management of heart rate can lower basic HR、notably basicHRV, pretest HR、HRV as well; raise achievement ratio of single-phase scan, ensureexcellent image quality and reduce radiation dose effectively.