[Relationship between lung-to-heart uptake ratio of technetium-99m-tetrofosmin during exercise myocardial single photon emission computed tomographic imaging and the number of diseased coronary arteries in patients with effort angina pectoris without myocardial infarction].

Objectives: Increased lung uptake of thallium-201 in exercise myocardial perfusion imaging is a reliable marker of multivessel disease in patients with ischemic heart disease. This study investigated whether the lung-to-heart uptake ratio with techenetium-99m(99mTc)-tetrofosmin also provides valuable information to detect patients with multivessel disease.

Methods: Fifty-three consecutive patients (35 men, 18 women, mean age 66 +/- 11 years; single-vessel disease: 29, double-vessel disease: 16, triple-vessel disease: 8) with stable effort angina pectoris without prior myocardial infarction and 17 control subjects (12 men, 5 women, mean age 62 +/- 9 years) underwent exercise myocardial perfusion imaging with 99mTc-tetrofosmin and coronary angiography in January 2000 to December 2002. The lung-to-heart uptake ratio was calculated on an anterior projection before reconstruction of the exercise single photon emission computed tomographic images.

Results: The mean lung-to-heart uptake ratio was 0.34 +/- 0.04, 0.38 +/- 0.07, 0.41 +/- 0.05, and 0.46 +/- 0.09, in patients with normal coronary, single-vessel disease, double-vessel disease, and triple-vessel disease, respectively. Significantly higher lung-to-heart uptake ratio was associated with more diseased vessels (p < 0.05). Multivessel disease could be detected with a sensitivity of 67% and a specificity of 74% if the cut-off point of the lung-to-heart uptake ratio was set as 0.4. Combining lung-to-heart uptake ratio with conventional myocardial perfusion imaging improved the sensitivity to detect multivessel disease to 83% and the specificity to 74%.

Conclusions: Lung-to-heart uptake ratio measured by exercise myocardial scintigraphy with 99mTc-tetrofosmin can provide clinically useful information to detect multivessel disease in patients with ischemic heart disease.