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log-likelihood is less than 1.0 are removed from the model. The bootstrap technique is similar to the jackknife technique."4 The basic concept of the technique as applied to the multiple logistic model is as follows. First, the parameters a and A are estimated by maximal likelihood. If the vectors of prognostic variables for the M individuals in the sample(More)
Previous results for the measurement of T1 as a means of monitoring temperature have demonstrated a linear calibration with a coefficient of the order of 1.5%/degrees C. We have studied the changes in T1 further, and observe that changes in tissue perfusion are substantial contributors to the effects observed, and that the model of what is happening is(More)
Fifteen patients with frequent anginal chest pain underwent diagnostic cardiac catheterization. After coronary arteriography a specially designed cardiac catheter was seated in the aortic root, permitting the continuous infusion of krypton-81m into the right and left aortic sinuses. A gamma camera, areas of interest and a visual display unit were used to(More)
Fifty patients who presented with angina pectoris were studied to examine the disturbances of regional myocardial perfusion during stress. Each patient underwent 16-point precordial mapping of the ECG during an exercise test, and coronary and left ventricular angiography. Regional myocardial perfusion was assessed using an atrial pacing test and a(More)
We describe a novel instrument which is capable of measuring the uptake of radioligand in human organs in vivo with the administration of very small doses of positron-emitting radioligands. This technique readily detects the displacement or reduced uptake of radioligand when a competitive agonist or antagonist is administered. This system provides no(More)
Fifteen patients with intractable angina pectoris underwent coronary angiography and coronary arterial bypass graft surgery. After the operation, a continuous infusion of krypton-81m was delivered into each graft. A gamma camera and multichannel analyzer were used to record the regional myocardial distribution of perfusion provided by each graft. The(More)
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