[Differentiation of hypertrophic cardiomyopathy from left ventricular hypertrophy induced by essential hypertension using magnetic resonance imaging].

To examine the efficacy of magnetic resonance imaging (MRI) in diagnosing hypertrophic cardiomyopathy (HCM), 16 patients with HCM and 14 hypertensives with left ventricular hypertrophy (LDH) were studied using a 0.5 Tesla Siemens MRI apparatus equipped with cardiac gating. In HCM, left ventricular hypertrophy was localized to the septal wall in four, to the apical wall in two, to both the septal and apical walls in two, and to the apical and inferior walls in one, and it was diffuse in seven patients. In hypertensives, LVH was localized to the septal wall in three, to both the septal and anterior walls in two, to the free wall in one, and it was diffuse in eight patients. The distribution of the hypertrophic portion was nearly equal in both groups. The thickest portion of the left ventricular wall was 24.6 +- 4.8 mm in HCM and 21.6 +- 5.4 mm in hypertension, and there was no significant difference between them. The T2 relaxation time of the hypertrophic portion was 52.2 +- 4.8 msec in HCM and 45.3 +- 6.1 msec in hypertension, and there was a significant difference between them (p less than 0.01). However, there were no significant differences between the T2 relaxation times of the hypertrophic and non-hypertrophic portions in both groups. In conclusion, it may be difficult to differentiate HCM from hypertension based on the distribution of hypertrophic portions, but measurements of the T2 relaxation times may be useful for making the differential diagnosis.