Quantitative Relationship of Stress Tc-99m Sestamibi Lung Uptake with Resting Tl-201 Lung Uptake and with Indices of Left Ventricular Dysfunction and Coronary Artery Disease

Background: We investigated the relationship of stress technetium 99m sestamibi lung uptake with rest thallium 201 lung uptake and with indices of left ventricular (LV) dysfunction and severity of coronary artery disease (CAD) in patients with known or suspected CAD undergoing stress testing and cardiac catheterization. Stress Tc-99m sestamibi lung uptake and both stress and rest Tl-201 lung uptake are associated with LV dysfunction and extent of CAD. Although the mechanism of lung uptake is thought to be similar for the two isotopes, their physiologic characteristics are different. No direct comparison of lung uptake for the two isotopes has been reported.

Methods And Results: We evaluated 192 consecutive patients who underwent dual-isotope myocardial perfusion imaging and cardiac catheterization within 30 days. We examined the relationship of stress Tc-99m sestamibi lung-to-heart ratio (LHR) with rest Tl-201 LHR, with indices of myocardial perfusion, and with invasive measures of the severity of LV dysfunction and CAD. Stress Tc-99m sestamibi LHR correlated with rest Tl-201 LHR (r = 0.548, P <.001). Stress Tc-99m sestamibi LHR was positively associated with LV filling pressures and extent of CAD and negatively associated with LV ejection fraction and arterial systolic blood pressure. However, after adjustment for multiple comparisons, stress Tc-99m sestamibi LHR was significantly associated only with LV end-diastolic pressure (r = 0.287, P =.002) and pulmonary capillary wedge pressure (r = 0.337, P <.001).

Conclusions: Increased stress Tc-99m sestamibi LHR correlates with rest Tl-201 LHR in patients with known or suspected CAD. Stress Tc-99m sestamibi lung uptake is also associated with invasively measured LV filling pressures.