Technetium-99m methoxy isobutyl isonitrile simultaneous evaluation of ventricular function and myocardial perfusion...

The authors evaluated the clinical applications of Tc-99m methoxy isobutyl isonitrile (MIBI) in the simultaneous assessment of ventricular function and myocardial perfusion in patients with congenital heart disease. Global ventricular function was assessed by first-pass ECG gated study. Myocardial perfusion was evaluated on images performed 1 hour after the injection of the tracer. Regional wall motion and systolic thickening were assessed by gated study acquired after the perfusion study. Two young patients were studied after a surgical Glenn procedure. The first patient, with a history of transposition of the great vessels and univentricular heart, had an ejection fraction of 44%. The left ventricle was dilated and the right ventricle was not appreciable. The septal and inferoapical regions showed reduced perfusion and reduced systolic thickening. The second patient, with a history of pulmonary atresia, septal defect and left ventricular hypoplasia, had a right ventricular ejection fraction of 37%. Regional wall motion, systolic thickening, and myocardial perfusion were normal. The right ventricle was hypertrophic and larger than the left ventricle. Thus, a single injection of Tc-99m MIBI allows noninvasive simultaneous assessment of global and regional ventricular function and myocardial perfusion in young patients with complicated congenital heart disease.