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The aim of this study was to investigate whether early (time 1, or T1) myocardial tetrofosmin imaging is feasible and as accurate in detecting coronary artery disease as is standard delayed (time 2, or T2) imaging. Methods: One hundred twenty patients (100 men and 20 women; mean age 6 SD, 61 6 10 y) with anginal symptoms underwent tetrofosmin gated SPECT. Stress/rest T1 imaging was performed at 15 min and T2 at 45 min after injection. Image quality was visually evaluated using a 4-point scale (from 0 5 poor to 3 5 optimal). Myocardial perfusion analysis was performed on a 20-segment model using quantitative perfusion SPECT software, and reversible ischemia was scored as a summed difference score (SDS). Coronary angiography was performed within 1 mo on all patients, and stenosis of more than 50% of the diameter was considered significant. Results: Overall, quality was scored as optimal or good for 94% of T1 images and 95% of T2 images (P 5 not statistically significant). Heart, lung, liver, and subdiaphragmatic counts did not differ for stress and rest T1 and T2 imaging. A good linear relationship was seen between T1 and T2 SDS (r 5 0.69; P , 0.0001), and Bland-Altman analysis showed good agreement between the 2 conditions. In terms of global diagnostic accuracy, areas under the receiver-operating-characteristic curve were comparable between T1 and T2 (0.80 vs. 0.81, P 5 not statistically significant). Discrepancies between T1 and T2 SDS were observed in 44% of patients (T1 2 T2 SDS . 2). Linear regression analysis showed a good correlation between T1 and T2 SDS (r 5 0.67; P , 0.0001), whereas the Bland-Altman method showed a shift in the mean value of the difference of 12.67 6 2.73. In patients with a T1 2 T2 SDS of more than 2, areas under the receiveroperating-characteristic curves were significantly higher for T1 than for T2 images (0.79 vs. 0.70, P , 0.001). Conclusion: T1 imaging is feasible and as accurate as T2 imaging in identifying coronary artery disease. However, in a discrete subset of patients, early acquisition strengthens the clinical message of defect reversibility by permitting earlier, more accurate identification of more severe myocardial ischemia.

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Objective To determine the best test(s) for predicting functional recovery of hibernating myocardium after reperfusion.Methods A prospective study to compare echocardiographic left ventricular diastolic wall thickness (d5 mm), low-dose dobutamine echocardiography and restredistribution thallium-201 scintigraphy, alone and in combination, for predicting recovery of left ventricular akinesis after surgical revascularization.Results Twenty-eight consecutive patients aged 58 9 years were studied. Of the 448 left ventricular segments, 263 were akinetic at rest; 230/263 (87%) had wall thickness d5 mm, 135 (51%) had a positive response and 175 (66·5%) were graded viable on thallium. Of akinetic segments 61% improved after surgery. Left ventricular score decreased from 2·3 0·4 to 1·8 0·4 (P<0·01) and ejection fraction increased from 27 10 to 37 14% (P<0·01). For predicting results at 1 year, diastolic wall thickness had a sensitivity and a predictive accuracy of a negative test of 100% but a specificity of 28% and predictive accuracy of a positive test of 61%. The addition of dobutamine echocardiography or thallium-201 improved the predictive accuracy of a positive test to 76% and 69%, respectively; the addition of both tests was not of greater benefit than that of a single test.Conclusions Diastolic wall thickness <5 mm on echocardiography was the best simple and single predictor of non-recovery of left ventricular dysfunction. The addition of dobutamine echocardiography or thallium-201, but not both, was the best solution for predicting recovery of left ventricular dysfunction. In times of limited resources, these findings are important from a clinical point of view.