Usefulness of cardiac fusion imaging with computed tomography and Doppler echocardiography in the assessment of conduit stenosis in complex adult congenital heart disease

Background: Noninvasive assessment of stenotic lesions in patients with complex adult congenital heart disease (ACHD) is challenging due to its complex morphology. The simultaneous two-screen display of multidetector-computed tomography (MDCT) and real-time echogram (STDME) technology can display a virtual multi-planar reconstruction from MDCT corresponding to the same cross-sectional image from transthoracic echocardiography (TTE). We investigated the usefulness of the STDME technology for stenosis severity assessment in complex ACHD patients. Methods: Twenty-four complex ACHD patients with stenotic lesions were enrolled in this study. All patients underwent TTE and the STDME technology within a week after MDCT. Peak velocity and pressure gradient (PG) across the stenotic site were measured using continuous wave Doppler. Cardiac catheterization was performed in 17 patients. Results: Nine out of the twenty-four patients had undergone repair with a conduit. Peak velocity and PG from the STDME technology were higher than those from TTE (peak velocity: 3.1 ± 1.1 vs. 2.8 ± 1.0 m/s; peak PG: 43 ± 28 vs. 34 ± 21 mmHg; both p < 0.01). Peak PG from the STDME technology showed significant correlations with those from catheterization in patients with a conduit (n=7) and those without a conduit (n=10) (r = 0.795 and 0.880, respectively; both p < 0.05), while peak PG from TTE was correlated with catheterization measurements only in patients without a conduit (r = 0.850, p < 0.05). Conclusions: The STDME technology enables more accurate assessment of conduit stenosis severity than does TTE in complex ACHD patients.