Measurement Of Aortic Root Diameter In Systole And Diastole By Two-Dimensional Echocardiography:A Comparative Study With Multidetector Computed Tomography

Objective:In this study,two-dimensional Echocardiography(2D-TTE)measures the diameters of the aortic root at different phases of the cardiac cycle by using the inner edge to inner edge(I-I)measurement method to comparing the differences between levels of the end-diastolic and end-systolic aortic roots.And then compared with the multidetector Computed Tomography(MDCT),to investigate the correlation,consistency,and repeatability of two imaging methods for aortic root diameter measurement.Methods:A total of 68 subjects who underwent 2D-TTE and ECG-gated MDCT examinations at the Sixth Hospital of Shanxi Medical University from February 2017 to December 2017 were collected,including 38 males and 30 females,with an average of(58.4± 14.5)years of age and record demographic and clinical features.Pregnancy,lactating women and children,iodine allergies,severe heart failure,hepatorenal insufficiency,arrhythmia,and poor quality 2D-TTE and/or MDCT images have been excluded.2D-TTE and ECG-gated MDCT were performed on all enrolled subjects.2D-TTE examination using the GE Vivid E9 color Doppler ultrasound diagnostic apparatus,configuration M5s-D ultrasound probe(frequency 1.75-4.25MHz).Obtain the parasternal long axis section of the aorta,at the end-diastole and end-systole,the aortic root was measured at the following four levels using the measurement of the anterior inner edge to inner edge(I-I),separately: the aortic annulus(Ao A),the sinuses of Valsalva(SVA),the sinotubular junction(STJ),and the proximal ascending aorta(PAAo),and make sure the measurement line is perpendicular to the long axis of the aorta.The MDCT was performed using a US GE 64-slice spiral CT scanner(LightSpeed VCT)in conjunction with a German Ulrich double cylinder high-pressure syringe and intravenous iodoproline contrast agent(specification: 100 ml,iodine concentration 370 mgl/ml).Acquiring and storing images,based on the original axial scan image,using a variety of post-processing techniques to obtain double oblique multi-planar reformatted images,the maximum diameter measured at the four levels of the aortic root above.Paired sample t-test,Pearson linear correlation,and Bland-Altman method were used to analyze the differences,correlation and consistency of the diameters of the aortic roots obtained by 2D-TTE and MDCT.Thirty subjects were randomly selected for reproducibility testing.Intraclass correlation coefficients(ICC)and Bland-Altman analysis were used to analyze intra-observer and intra-observer variability.Statistical significance was considered as P<0.05.Results:(1)All subjects had no difference in gender,BMI,blood pressure,heart rate,etc.between women and men,and height and weight of women were smaller than men.(2)2D-TTE measured the diameter of the aortic root at end-diastole: Ao A: 20.1±2.9 mm,95% confidence interval(CI)was(14.4,25.8)mm;SVA: 30.4±3.3 mm,95% CI was(23.8,36.9)mm;STJ: 26.2 ± 3.2 mm,95% CI was(19.9,32.5)mm;PAAo: 32.0 ± 3.2 mm,95% CI was(25.8,38.3)mm.2D-TTE measured the diameter of the aortic root at end-systole: Ao A: 20.9±2.8 mm,95% CI was(15.3,26.40)mm;SVA: 31.3±2.8 mm,95% CI was(25.8,36.8)mm;STJ: 27.2±3.1 mm,95% CI was(21.3,33.2)mm;PAAo: 33.3±3.0 mm,95% CI was(27.4,39.1)mm.The diameters of the aortic roots measured by MDCT: the aortic annulus: 21.7±2.6 mm,95% CI was(16.5,26.9)mm;the sinuses of Valsalva: 31.7±2.4 mm,95% CI was(27.0,36.4)mm;the sinotubular junction: 27.7±2.9 mm,95% CI was(22.0,33.3)mm;the proximal ascending aorta: 33.7±2.9 mm,the 95% CI was(28.1,39.3)mm.(3)There was a was a statistically significant difference between the diameters of the aortic roots measured by 2D-TTE at end-diastole and end-systole;and a was a statistically significant difference between the aortic root diameter measured by MDCT and 2D-TTE at end-diastole.Therefore,a was a statistically significant difference exist in the Ao A diameters measured by MDCT and 2D-TTE at end-systole,but there was no significant difference in SVA,STJ,and PAAo levels.(4)There was good correlation and consistency between MDCT and 2D-TTE at end-diastole and end-systole.The correlation coefficient r values of 2D TTE end-diastole and MDCT in AoA,SVA,STJ and PAAo were 0.861,0.905,0.919,and 0.852,respectively;and the correlation coefficient r values of 2D TTE end-systole and MDCT in AoA,SVA,STJ and PAAo were 0.893,0.910,0.939,and 0.878,respectively.(5)The measurements by 2D-TTE at end-diastole and end-systole and MDCT have good repeatability: The correlation coefficient ICC value of the 2D-TTE observer at end-diastole was as follows: Ao A 0.92,SVA 0.87,STJ 0.91,PAAo 0.90;and the correlation coefficient ICC values between observers were: 0.87 in AoA,0.85 in SVA,0.87 in STJ,and 0.86 in PAAo.The correlation coefficient ICC value of the 2D-TTE observer at end-systole was as follows: Ao A 0.91,SVA 0.90,STJ 0.93,PAAo 0.91;and the correlation coefficient ICC values between observers were: 0.88 in AoA,0.86 in SVA,0.89 in STJ,and 0.89 in PAAo.And the correlation coefficient ICC values of MDCT observers were: AoA 0.94,SVA 0.93,STJ 0.96,and PAAo 0.91;and the correlation coefficient ICC values between the observers were: 0.92 in Ao A,0.88 in SVA,0.91 in STJ,and 0.86 in PAAo.Conclusion:The diameter of the aortic root at the end-systole was significantly greater than that at the end-diastole.Compared with end-diastole measurements,the diameters of the aortic root measured by 2D-TTE using inner-inner measurement method at end-systole are more similar with the MDCT measurements,and have better comparability;2D-TTE and MDCT have good correlation and consistency in the measurement of aortic root diameter,and both imaging techniques have good reproducibility.