Noninvasive measurement of pulmonary vascular resistances by assessment of cardiac output and pulmonary transit time.

Rationale And Objectives: Pulmonary vascular resistance is of special interest in many diseases. Usually it is determined invasively by catheterization, but cardiac output and pulmonary transit time can be ascertained by several noninvasive methods.

Methods: Fourteen heart recipients (age 34-71 years) were examined by electron-beam CT of the heart. Cine and flow studies were performed using a total of 60 mL of contrast and a breath-hold of 20 seconds.

Results: A mathematical model for calculating pulmonary vascular resistances from noninvasively measured cardiac outputs and pulmonary transit times was developed. Right-sided heart catheterization served as the reference method.

Conclusions: The formula created seems to allow a clinically valid estimate of pulmonary vascular resistance from noninvasively acquired data.