ANALYSIS OF CARDIAC-FUNCTION BY MRI AND STEREOLOGY

Design-based stereology and phase contrast magnetic resonance imaging (MRI) were combined to monitor changes in the volume of the four chamb ers of the human heart during the cardiac cycle, The data set consiste d of 18 adjacent slices (or 'scanning levels') of 0.5 cm thickness, pe rpendicular to the long axis of the body, and encompassing the whole h eart of a healthy volunteer, At each scanning level, a cardiac gated M R image was obtained at each of 16 equally spaced time frames within t he cardiac cycle. Given stationarity with respect to time, absence of image artefacts and appropriate definition of chamber boundaries, for each time frame unbiased estimates of total blood volume in the releva nt heart chambers were efficiently obtained using the Cavalieri method and point counting, Combined with a proper MRI acquisition, modern st ereological methods constitute an efficient and reliable tool to quant ify cardiac function noninvasively.