[An Examination of Variable Image Positions in the Aortic Valve Blood Flow Using Phase Contrast MRI: Effect of Breath-holding Methods in Healthy Volunteers].

Phase contrast MRI (PC-MRI) is a useful tool for evaluating valvular pathology. In addition, PC-MRI can provide a noninvasive assessment of blood flow in an arbitrary cross section. However, the blood flow measurement with breath-hold or free breath PC-MRI may be different from each other because of intrathoracic pressure changing and variable image position.

[Estimation of precision in system suitability tests].

In system suitability tests, the daily conditions of an analytical instrument are checked with the standard deviation (SD) of measurements as a criterion. This paper examines how exactly the SD values obtained from the measurements can indicate instrumental conditions. The HPLC measurement for acetaminophen is repeated six times daily to obtain an SD estimate, and these procedures are repeated for seven days.