Diagnostic quality of steady state free precession imaging of cardiac valve morphology in pediatric/congenital heart disease

Objective

To evaluate cine Cardiac Magnetic Resonance – Steady State Free Precession (CMR-SSFP) imaging quality and diagnostic accuracy in the assessment of cardiac valve morphology.

Background

Evaluation of cardiac valve morphology has not been considered an indication for cardiac MRI due to suboptimal imaging quality; few studies have examined this objectively. MRI techniques utilizing CMR-SSFP may have overcome this limitation. Evaluation of CMR-SSFP diagnostic imaging quality in the assessment of valve morphology has not been performed for pediatric/congenital heart disease. Comparison of CMR-SSFP diagnostic accuracy of aortic valve morphology to echocardiography has not been previously performed.

Methods

We retrospectively reviewed 234 consecutive pediatric/congenital cardiac MRI cases. A diagnostic clarity score (Table 1) was assigned to the tricuspid, mitral valve annulus, leaflets, chordae and papillary muscles. High-quality diagnostic imaging is defined as a clarity score of 1 or 2. The clarity score of the mitral (Figure 1) and tricuspid valves was assessed by examination of standard cine CMR-SSFP imaging in two-chamber, four-chamber and short-axis views. Clarity score of the aortic valve annulus and leaflets was assessed when long axis imaging of the left ventricular outflow tract and cross-sectional imaging of the aortic root were performed. Among patients with aortic valve imaging, we compared morphologic diagnosis by CMR-SSFP to echocardiography.

Table 1 Diagnostic clarity score

Figure 1

Mitral valve.

Results

Patient age ranged from 1 month to 65.1 years (average 17.2 years). Table 2 illustrates the proportion of valve components with a high diagnostic clarity scores. There was no difference in weight or body surface area between those with an average mitral or tricuspid clarity score of < 2 (excellent or very good clarity) vs. ≥ 2 (fair to poor clarity). Among the 39 cases with aortic valve specific imaging, 27 (69%) had an echocardiogram for comparison. CMR-SSFP correctly identified the aortic valve morphology in all 27 cases. CMR-SSFP correctly identified the affected commissure in 13 of 13 bicommissural aortic valves (Figure 2) and correctly identified 14 of 14 tricommissural aortic valves.

Table 2 Proportion of valve components with a high-quality diagnostic imaging (Diagnostic clarity scores 1 or 2)

Figure 2

Biocommisural aortic valve.

Conclusion

In the majority of cases CMR-SSFP produces high diagnostic quality imaging of cardiac valve morphology in congenital/pediatric cardiac MRI. The valve components with the highest diagnostic clarity score are tricuspid and mitral valve annuli, leaflets and papillary muscles and aortic valve annuli and leaflets. CMR-SSFP however produced high clarity images of chordae in only a minority of cases. Aortic valve morphology can be diagnosed with a high degree of reliability.