The Effects Induced By Heart Rate and Its Fluctuation to the Image Quality of 64-Slice CT in Coronary Angiography

Objective To explore the effects induced by heart rate and its fluctuation to the image quality of 64-slice CT in Coronary Angiography.Methods A retrospective study was undertaken in 596 cases which had 64-slice CT scan in coronary angiography.These data were divide to four groups: A: 60 bpm,B: 61-70 bpm,C: 71-80 bpm,D: 80 bpm.Then each group were subdivide to four subgroups:1: 1~5 times/ min,2: 6~10 times/ min,3: 11~15 times/ min,4: 15 times/ min.Another 50 cases whose heart rate were in the range of 50~65 bpm with no obvious fluctuation were set as the controlled group.The quality of 64-slice CT between the test group and the controlgroup were compared.Then the relation between fluctuation of heart rate and the image quality was analyzed by linear tendency χ2 test.If the linear relation was denied,logistic regression was used instead of the χ2 test.Results Significant difference were exists between the A3、A4、B3、B4、C3、C4、D1、D2、D3、D4 groups and the control.With the heart rate and its fluctuation increasing,the imaging quality of coronary decrease obviously.The effects induced by fluctuation of heart rate were much more than heart rate does.Conclusion When the heart rate is less than 80bpm and the heart rate fluctuation is less than 10 times/min the quality are much better.When the heart rate fluctuation is between 11-15 times/min we could diagnose with the quality pictures.While when the heart rate is more than 80bpm or the heart rate fluctuation is more than 15 times/min the quality are too bad to diagnose.