MRI in hypertrophic cardiomyopathy: a morphofunctional study.

OBJECTIVE: We compared MRI with two-dimensional echocardiography (2dE) and Doppler echocardiography to determine the diagnostic role of MRI in hypertrophic cardiomyopathy (HCM).

MATERIALS AND METHODS: Twenty-three patients with 2dE diagnosis of HCM were examined with MRI; 12 of 23 patients were also studied by color (cDE) and continuous wave (cwDE) Doppler echocardiography. Morphologic information and diastolic heart wall thickness were obtained by SE sequences; functional study was performed by gradient echo sequences (cine MR).

RESULTS: The correlation between MR, SE sequences and 2dE was better for septal (r = 0.930, p < 0.01) than for posterolateral (r = 0.739, p < 0.01) wall thickness. The assessment of the distribution of the hypertrophy was changed by MR in five cases. Cine MR functional study showed a systolic subaortic signal void (dynamic obstruction) in 12 of 22 patients and a systolic left atrial signal void (mitral regurgitation) in 17 of 22. Systolic wall thickening was studied by cine MR and 2dE in 11 patients: A good correlation was found for septum (0.01 < p < 0.05) and a poor one for posterolateral wall (p > 0.05). The cine MR and cDE turbulence duration in the left ventricle and atrium showed excellent correlation (p < 0.01). Good agreement was found between the duration of subaortic turbulence (cine MR or cDE) and the pressure gradient (cwDE) (p < 0.01 and 0.01 < p < 0.05, respectively) and between cine MR and cDE semiquantitative estimate of the mitral regurgitation (p < 0.01). In all patients with subaortic MR signal void studied with cwDE, a pressure gradient was present.

CONCLUSION: Magnetic resonance imaging can play an important role in the diagnosis of HCM after 2dE-DE.