Diagnostic Value of Visualization of the Right Ventricle Using Thallium-201 Myocardial Imaging

The diagnostic significance of visualizing the right ventricle on thallium-201 myocardial perfusion scans (T-scan) at rest was studied in 53 patients. In 33 patients the right ventricle was visualized clearly on the T-scan (group A). Hemodynamic evidence of right ventricular hypertension with systolic pressure > 30mm Hg was present in 28 of 33 (85%) of these patients. Right ventricular volume overload with left-to-right shunt > 2: 1 was present in three patients. Other tests were diagnostic for right ventricular enlargement and or pulmonary hypertension as follows: chest x-ray (58%), echocardiogram (36%) and electrocardiogram (15%). In an unselected group of 20 patients (group B) where resting T-scan did not show visualization of the right ventricle, the right ventricular systolic pressure was < 30 mm Hg in all. The other noninvasive tests did not reveal presence of right ventricular hypertrophy or enlargement. T-scan appears to be a useful and sensitive test in detecting right ventricular pressure or volume overload compared with other noninvasive tests. This may be useful in detection of patients with right ventricular hypertrophy or enlargement secondary to pulmonary hypertension or other causes.