Assessment Of Left Ventricular Function Using DSCT: Comparison With Echocardiography

Objective:To assess the value of DSCT in the evaluation of left ventricular function, compare with echocardiography.Methods:Forty patients with cardiac diseases were studied with DSCT and echocardiography, from August 2008 to January 2009, 11 female patients,29male patients mean age 63.95±13.16, the interval time between two examination is not exceed two weeks.Twenty series of images were reconstructed at every 5% throughout the cardiac cycle. From the reconstructed cardic planes CT images(left ventricle short axle, left ventricular long-axis and four-chamber view), quantitative information on ventricular volume changes throughout the cardiac cycle can be derived. The appropriate reconstruction windows for the systolic and diastolic phases are visually identified as the images showing the minimum and maximum ventricular diameter and checked against the ECG. The systolic phase is usually found at 20%-40% of the RR-interval and the end-diastolic phase at around 85%-95%. Diastolic and systolic left ventricular volumes were measured using circulation software of DSCT, including left ventricular outflow tract and papillary muscle. Diastolic and systolic left ventricular volumes can be calculated using standard software for distance and area measurements with the Simpson's method. For the analysis of global function, only the endocardial borders of the left ventricle are needed. The results measured by cardiac DSCT were compared with those obtained by echocardiography..Echocardiography was performed using HP Sonos-5500 by two chief ultrasound experts using M-Mode Color Doppler.Statistical Analysis: paired t test, Pearson's correlation coefficient and Linear regression analysis were performed to determine the correlationnd limits of agreement for the LV end-diastolic nd end-systolic volumes, stroke volume,and ejection fraction between DSCT and echocardiography..Results:DSCT can segment the ventricle volumes from the thin-slice data set and support the accurate analysis of global cardiac function parameters. The measurements of end-diastolic volume(EDV) ,end-systolic volume (ESV) , stroke volume ( SV) ,and ejection fraction ( EF) with DSCT imaging technique were closely correlated with those obtained by echocardiography,There was no statistically significant difference between the measurements of the two methods ( P > 0. 05) . The correlation coefficients were 0.698～0.891. Two patients with left heart insufficiency were found in our study,EF of DSCT was lower than that of echocardiography.Conclusion:(1) Compare with echocardiography, left ventricular function indexes tested by DSCT were accurate, the correlation of the results was quite well. (2) DSCT scanner with increased temporal resolution of 83 milliseconds to assess functional parameters during the whole of the cardiac cycle. Thin-layer high SNR images without motion artifacts lead to reliable results.(3) Functional assessments with DSCT were carried out complementary to coronary CTA, and the imaging protocols are the same. Since information on virtually any cardiac phase is contained in an ECG-gated DSCT spiral data set, images from end-systolic and end-diastolic phases can be retrospectively produced using ECG gating without the need for additional radiation exposure or administration of contrast material.