Feasibility and reproducibility of off-line tissue Doppler measurement of regional myocardial function during dobutamine stress echocardiography.

AIMS: Off-line post-processing of colour tissue Doppler from digital loops may allow objective quantification of dobutamine stress echocardiography. We assessed the reproducibility of off-line measurements of regional myocardial velocities. METHODS AND RESULTS: Nine observers analysed 10 studies, each making 2400 observations. Coefficients of variation in basal segments from apical windows, at rest and maximal stress, were 9-14% and 11-18% for peak systolic velocity, 16-18% and 17-19% for time-to-peak systolic velocity, 9-17% and 18-24% for systolic velocity time integral, and 18-23% and 21-27% for systolic acceleration. Coefficients of variation for diastolic velocities in basal segments at rest were 11-40%. Coefficients of variation for peak systolic velocity were 10-24% at rest and 14-28% at peak in mid segments, and 19-53% and 29-69% in apical segments. From parasternal windows coefficients of variation for peak systolic velocity were 14-16% in basal posterior, and 19-29% in mid-anterior segments. High variability makes measurement unreliable in apical and basal anterior septal segments. The feasibility of obtaining traces was tested in 92 subjects, and >90% in all basal and mid segments apart from the anterior septum. CONCLUSION: Quantification of myocardial functional reserve by off-line analysis of colour tissue Doppler acquired during dobutamine stress is feasible and reproducible in 11 segments of the left ventricle. The most reliable measurements are systolic velocities of longitudinal motion in basal segments

First g-factor measurement using a radioactive 76^{76}Kr beam

The g factor of the first 2+ 1 state of radioactive 76Kr ( T 1/2 = 14.8 h) has been measured using projectile Coulomb excitation in inverse kinematics combined with the transient magnetic-field technique. The 76Kr beam was produced and accelerated in batch mode (re-cyclotron method) at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. The g factor g(76Kr; 2+ 1) = +0.37(11) was obtained