Nitrate-enhanced thallium 201 single-photon emission computed tomography imaging in hibernating myocardium

Objectives This study tested the usefulness ai nitrate-enhanced thallium 20 1 imaging for detecting myocardial viability. Background Previous work suggests that nitrates enhance the ability of Tl-2 01 imaging to detect viable myocardium. Methods Eighteen patients with coronary artery disease underwent Tl-201 ima ging at rest, after 4 hours of redistribution, and during intravenous nitro glycerine infusion (mean dose = 5.96 +/- 5.37 mu g/kg/min). Twelve patients had their echocardiograms repeated after revascularization. Perfusion and wall motion were scored from 0 to 2 (absent to normal). Results all the regions identified or viable by the rest/redistribution pai r of scans were identified as viable by the rest/nitroglycerine pair of sca ns. Ninety-one percent of these regions were identified as viable by the si ngle nitroglycerine scan alone. In patients who underwent revascularization , the total Tl-201 perfusion score improved from 193 to 214 after revascula rization (P =.009). Wall motion score improved from 151 to 168 after revasc ularization (P =.09). Both the rest/nitroglycerine and rest/redistribution studies correctly predicted 14 (88%) of 16 regions that improved after reva scularization. Most importantly, the rest/nitroglycerine and rest/redistrib ution studies were able to predict postrevascularization myocardial viabili ty (absence of akinesis or dyskinesis after revascularization), with a sens itivity of 95% and 92%, respectively, and a predictive accuracy of 84.4%. Conclusions Nitroglycerine infusion during Tl-201 imaging is a useful techn ique for detecting underperfused, viable myocardium, requires less time to perform than rest/redistribution imaging, and may allow detection of viable myocardium with a single Tl-201 single-photon emission computed tomographi c study.