Estimation of average flow in ungated 3D phase contrast angiograms

Three dimensional (3D) phase contrast angiograms contain velocity data, which is discarded after the reconstruction of the projections. In extension to earlier work on velocity quantification with ungated 2D phase data, this paper shows that a useful estimate of the average velocity and flow rate can be extracted from ungated 3D phase contrast angiograms. Simulations and experiments in a phantom and in vivo were performed. For pulsatile flow and strong spin saturation, an over-estimation of the flow rate at the net in-flow end of the imaging volume and underestimation at the net out-flow end was observed. Imaging at lower RF tip angles yielded flow rates close to the correct value within the entire imaging volume. In contrast to ungated 2D experiments, the flow rates determined by repeated 3D experiments showed no variation.     

Minor Psychiatric Morbidity, Its Prevalence and Outcome in a Cohort of Civil Servants A Seven-year Follow-up Study

During the years 1979–1986, a cohort of direct entrantexecutive officers in the Civil Service were followed up toexamine the prevalence and outcome of minor psychiatric morbidityin an occupational setting. All studies using epidemiologicalstandardized research methods agree, that prevalence rates arehigh in occupational settings. As in primary care settings,half of the illness episodes followed a chronic course, whichemphasizes the need for early detection and prompt managementof these conditions, and for evaluative studies of interventionstrategies.