The primary findings of this study are as follows: 1. In the preoperative assessment of the aortic root, MDCT demonstrates superior correlation and consistency compared to TEE, particularly because of the greater accuracy of the D-area and D-circ methods; 2. For irregular annulus, such as in BAV patients, MDCT exhibits significant advantages in measurement; 3. High-quality MDCT images are valuable for preoperative geometric height measurements.
Previous studies have commonly employed echocardiography to evaluate the aortic valve and aortic root14. As the most commonly utilized diagnostic modality for preoperative assessment of the aortic root, echocardiography provides comprehensive anatomical information on the root and assesses aortic valve function. It enables real-time visualization of the physiological status of the aortic valve and aortic root for surgeons, facilitating the evaluation of aortic valve regurgitation mechanisms, the assessability of aortic valve repair, and the formulation of corresponding surgical strategies12. Our study employed Bland‒Altman analysis and correlation analysis to compare the relationships between MDCT and TEE measurements of the aortic annulus, sinus of Valsalva, and STJ. The findings revealed a high level of consistency between MDCT and TEE. Consequently, MDCT has emerged as a viable method for the preoperative assessment of the aortic root.
MDCT has significant advantages in measuring the diameter of the aortic root. Although there is controversy in guideline recommendations, there is a consensus within the industry on the methodology for measurements. The I-I method is most commonly employed in MDCT measurements when contrast is administered, as the wall itself is scarcely visible. Conversely, the O-O method is utilized for noncontrast-enhanced scans15.
Echocardiography is also commonly employed for the measurement of effective height and geometric height. However, in comparison to echocardiography, MDCT offers superior spatial resolution, providing a significant advantage in measuring root dimensions such as geometric height and effective height. As a result, there is a growing body of research utilizing MDCT for the assessment of aortic root dimensions16. Our study revealed a high degree of similarity between MDCT and TEE results in assessing geometric height, demonstrating a high level of reliability. However, in measuring effective height and free margin length, both MDCT and TEE have certain limitations, and the majority of studies still rely on intraoperative measurements.
In comparison to TAV patients, BAV patients often exhibit an elliptical or irregular valve annulus. In a previous study, the BAV annulus was measured separately at the level of the sinus of the valsava because it was not possible to measure three cusp-to-commissure distances in the BAV15. Our study revealed that MDCT has a distinct advantage for annulus diameter measurements in BAV patients. Furthermore, our findings indicate a greater correlation between MDCT and TEE in BAV patients. Compared to intraoperative measurements, MDCT exhibited greater accuracy, with the highest precision observed in D-area measurements, followed by D-circ measurements.
The main limitations of this study are as follows: 1) our study used a 64-slice spiral multidetector scanner, as opposed to a 128-slice scanner, which entails much more strict control of heart rate and a high dose of radiation; 2) in our study, all MDCT measurements were taken at 75% of the cardiac cycle, which is consistent with previous and current guidelines that favor the use of measurements in the systolic phase; though, there is no evidence supporting better consistency between diastolic measurements and intraoperative findings; and 3) compared to previous series from Western or other Asian countries, our cohorts are very young and cannot be applied to other scales. 4) This study was unable to assess the status of the aortic root in patients with impaired renal function who could not undergo MDCT and those with suboptimal image quality due to elevated heart rate during examination or inability to breath-hold. 5) The exclusion of a healthy control group in this study diminishes the generalizability of the research findings.