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Metastable events in ADC comparators cause large errors that cannot be tolerated in test and measurement applications that record data over extended time intervals. This work utilizes BiCMOS technology to provide high dynamic range analog to digital conversion at 2.5GS/s with a metastable error rate of less than one error per year and better than 78dB SFDR(More)
The potential of ungated computed tomography (CT) to detect and quantify myocardial infarctions was assessed in 10 dogs. Twenty-seven in vivo CT examinations were performed at various time intervals (1 hr-20 days) after coronary artery occlusion. After intravenous contrast administration, CT delineated the infarcted myocardium in all 27 studies. The(More)
Magnetic resonance (MR) images of the shoulders of a healthy volunteer were obtained in axial, sagittal, and coronal orientations using a 0.5-T imaging system. Multiple high-resolution spin-echo images were generated using an off-center zoom technique and a specially designed surface coil. Several anatomic structures, including the rotator cuff, long biceps(More)
The ability of proton NMR relaxation times to detect cardiac allograft rejection was studied in an inbred rat heterotopic cardiac transplantation model. Hearts from 25 Lewis X Brown Norway F1 hybrid rats were anastomosed to the abdominal aorta and vena cava of Lewis recipients; 25 Lewis donor hearts served as isograft controls. Groups of five allografts and(More)
Nuclear magnetic resonance spectroscopy was used to study the effect of chronic hypoxia on both right (RV) and left ventricular and septal (LV + S) muscle. Rats in the hypoxic group, kept in a hypobaric chamber at 1/2 atm pressure for 2 weeks, developed right, but not left, ventricular hypertrophy (p less than 0.001). Tissues were studied within 2.5 h of(More)
The proton NMR relaxation times of lung tissue were determined in a rabbit model of acute and evolving pulmonary hemorrhage (PH). Pure PH was simulated by injecting blood into a single lobe using endobronchial catheterization. In vitro spectroscopic measurements of T1 and T2 were made and total water content was determined on lung samples that were excised(More)
The purpose of this study was to establish the proton NMR relaxation times of collapsed but otherwise normal lung tissue and to determine whether an inflammatory process within a collapsed lung can be detected by alterations in relaxation times. The lungs of three groups of rabbits were studied: group A (n = 7) had a sterile collapse of one lung for two(More)