Multimodality imaging of the aortic root and ascending aorta: a comparative study of CTA and echocardiography

Background Accurate evaluation of the aortic root (AoR) and ascending aorta (AscA) is essential for determining surgical timing and guiding longitudinal surveillance in TAD. While computed tomography angiography (CTA) offers unmatched structural resolution, transthoracic echocardiography (TTE) provides functional and hemodynamic insight into the aortic valve – a significant factor that can influence disease trajectory and surgical planning. This study assessed the agreement between TTE and CTA in measuring aortic dimensions in patients with TAD and their complementary roles in clinical decision-making. Purpose To evaluate the correlation and agreement between transthoracic echocardiography (TTE) and computed tomography angiography (CTA) in measuring aortic root and ascending aorta dimensions, and to define their complementary roles in managing thoracic aortic disease. Methods We retrospectively analyzed consecutive adult patients (≥18 years) who underwent both TTE and CTA between 2019 and 2025 (n = 2072). Exclusion criteria included connective tissue disorders and prior aortic surgery. AoR and AscA diameters were extracted from validated reports and independently verified by two blinded observers. The study cohort (n = 278; mean age 64.4 ± 12.2 years; 74.8% male) was analyzed using linear regression and Bland–Altman methods to assess correlation and agreement. Subgroup analyses evaluated the effect of valve morphology and function. Statistical analyses were performed in SPSS (v31.0.1) R (v4.3.2), with p < 0.05 considered significant. Results Correlation between modalities was strong for both AoR (R = 0.77, R² = 0.59, p < 0.001) and AscA (R = 0.73, R² = 0.53, p < 0.001). TTE slightly underestimated diameters compared with CTA, particularly in larger or asymmetric aortas. Mean bias was near zero, with 95% limits of agreement within ±2 mm. In patients with valve dysfunction, TTE provided key functional data influencing surveillance follow-up. In a smaller subgroup (n = 25) undergoing magnetic resonance angiography (MRA), measurements closely matched CTA for the root and were marginally smaller for the ascending aorta (mean difference <3 mm), confirming MRA as a reliable, radiation-free alternative for morphometric assessment. Conclusions CTA remains the gold standard for detailed anatomic assessment and surgical planning, whereas TTE provides vital functional insights and accurate longitudinal measurements without radiation or contrast exposure. Combining both modalities enables a more comprehensive evaluation, optimizing surgical decision thresholds and supporting personalized management of TAD.