Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
The natural history of thoracic aortic aneurysm (TAA) is one of progressive expansion. Asymptomatic patients who do not meet criteria for repair require conservative management including ongoing aneurysm surveillance, mostly carried out by contrast-enhanced computed tomography angiography (CTA).
Purpose
To prospectively compare image quality and reliability of a prototype non-contrast, self-navigated 3D whole-heart magnetic resonance angiography (MRA) with contrast-enhanced computed tomography angiography (CTA) for sizing of thoracic aortic aneurysm (TAA).
Methods
Self-navigated 3D whole-heart 1.5 T MRA was performed in 20 patients (aged 67 ± 8.6 years, 75% male) for sizing of TAA; a subgroup of 18 (90%) patients underwent additional contrast-enhanced CTA on the same day. Subjective image quality was scored according to a 4-point Likert scale and ratings between observers were compared by Cohen’s Kappa statistics. Continuous MRA and CTA measurements were analyzed with regression and Bland-Altman analysis.
Results
Overall subjective image quality as rated by two observers was 1 [interquartile range (IQR) 1-2] for self-navigated MRA and 1.5 [IQR 1-2] for CTA (p = 0.717). For MRA a perfect inter-observer agreement was found for presence of artefacts and subjective image sharpness (κ=1). Subjective signal inhomogeneity correlated highly with objectively quantified inhomogeneity of the blood pool signal (r = 0.78-0.824, all p <0.0001). Maximum diameters of TAA as measured by self-navigated MRA and CTA showed excellent correlation (r = 0.997, p < 0.0001) without significant inter-method bias (bias -0.0278, lower and upper limit of agreement -0.74 and 0.68, p = 0.749). Inter- and intraobserver correlation of aortic aneurysm as measured by MRA was excellent (r = 0.963 and 0.967, respectively) without significant bias (all p ≤ 0.05).
Conclusion
Self-navigated 3D whole-heart MRA enables reliable contrast- and radiation free aortic dilation surveillance without significant difference to standardized CTA while providing predictable acquisition time and by offering excellent image quality.
Abstract Figure.
Diagnostic and surgical management of patients with aneurysms of the thoracic aorta with various causes. Echocardiography and contrast enhanced computed tomography in prophylactic replacement of the ascending aorta.
