[Correlation of effective temporal resolution and accuracy of volume ejection fraction on the ECG-gated cardiac MDCT].
OBJECTIVE
ECG-gated cardiac MDCT offers many cardiac clinical applications. The goals of this report are 1) to introduce a new concept of effective reliability (ER) from effective temporal resolution for the evaluation of ejection fraction (EF) and evaluation of image quality (IQ) of coronary arteries, and 2) to show the correlation of ER and the accuracy of EF with different cardiac reconstruction algorithms and different rotation speeds.


METHODS
To assess the accuracy of EF, helical scanning was performed with a gated cardiac MDCT (GE LightSpeed, 8/16 slice) on pulsating cardiac coronary phantoms (0.5 and 0.6 sec rotation speed for each 50-110 bpm, 5-bpm step). We define effective reliability (ER) from effective temporal resolution (%) as follows: ER= (1-TR/HC) x 100; TR: Effective temporal resolution, HC: time of heart cycle in each bpm.


RESULTS
From the results of the EF measurement and calculated ER, high accuracy was obtained by using optimal scan conditions (optimal rotation speed and cardiac reconstruction algorithm) in a wide range of heart rates (heart rate<90: EF & ER>81%; heart rate<110 bpm: EF & ER>73%). Results showed that the calculated ER is closely correlated with the measurement results of EF based on the phantom experiment (R2=0.901+/-0.075; Max: 0.994, Min: 0.738). Optimal reconstruction thickness can reduce total image number for the evaluation of EF.


CONCLUSIONS
We concluded that the ER is useful to evaluate EF accuracy and the IQ of images of coronary arteries.
Shen
Yun
Y
GE Yokogawa Medical Systems, Ltd.
Jinzaki
Masahiro
M
Sato
Kozo
K
Kuribayashi
Sachio
S
D004562:Electrocardiography; D006321:Heart / Q000000981:diagnostic imaging* / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D019047:Phantoms, Imaging; D013318:Stroke Volume / Q000502:physiology*; D013995:Time; D014057:Tomography, X-Ray Computed / Q000379:methods*