Evaluation of cor pulmonale on a modified short-axis section of the heart by magnetic resonance imaging.

Magnetic resonance imaging (MRI) of a modified short-axis section of the heart, in 36 patients with chronic pulmonary diseases, consisting of 19 patients with pulmonary hypertension (PH group; mean pulmonary arterial pressure > or = 20 mm Hg) and 17 patients without pulmonary hypertension (non-PH group) was evaluated to study the configuration of the right ventricle. Parameters of right ventricular hypertrophy, including right ventricular wall thickness (RVWT) and the ratio of RVWT to left ventricular posterior wall thickness (RVWT/LVPWT), with this method were significantly larger in the PH group than in the non-PH group (p < 0.01). RVWT and RVWT/LVPWT correlated well with mean pulmonary arterial pressure (r = 0.90, p < 0.001 and r = 0.89, p < 0.001), total pulmonary resistance (TPR; r = 0.88, p < 0.001 and r = 0.85, p < 0.001), and pulmonary arteriolar resistance (PAR; r = 0.83, p < 0.001 and r = 0.81, p < 0.001). This method of setting a patient in a supine position and slicing with single-oblique sections may seem overly simple compared with Dinsmore's double-oblique short-axis section of the heart, but it is more convenient in practice. These results suggest that a modified short-axis section of the heart by MRI provides valid clinical configurational information concerning the right ventricle on which to base a noninvasive diagnosis of cor pulmonale.