Visualizing high-resolution volumetric medical datasets is a challenging task. Current off-the-shelf graphics hardware supports interactive texture-based volume-rendering of volumetric datasets up to a resolution of 512 3 data points only. We present a method that allows us to visualize higher-resolution datasets, providing images similar to texture-based volume-rendering techniques at interactive frame-rates and full resolution.Our approach is based on an out-of-core point-based rendering approach. We pre-process the data by grouping points in the given dataset according to their value on disk and read them, when needed, from disk to immediately stream data to the rendering hardware. The high resolution of the dataset and the density of the data points allows us to use a pure point-based rendering approach. The density of points with equal or similar values within the dataset can be considered as being high enough to display regions and contours using points only.With our data-stream based approach we achieve interactive frame-rates for volumes even exceeding 512 3 resolution. Interactivity is not restricted to navigation through the dataset itself. It is also possible to change the values of interest to be displayed in real-time, enabling us to change display-parameters and thus looking for interesting and important features and contours interactively. For a human brain extracted from a 753x1050x910 colored dataset we achieved frame-rates of 20 frames/second and more, depending on the values selected.We describe a new way to interactively display high-resolution datasets without any loss of detail. By using points instead of textured volumes we reduce the amount of data to be transferred to the graphics hardware when compared to hardware-supported texture-based volume rendering. Using a data-organization optimized for reading from disk, we reduce the number of disk-seeks, and thus the overall update-time for a change of parameter-values.