[Modification of the NMR-tomogram by blood flow]

Blood flow causes alterations of the NMR-Signal. Cross-sections of vessels will sometimes be imaged as dark spots, sometimes as highlighted areas. These highlightings of the lumen of vessels are often interpreted as caused by obstruction. In this paper the mechanisms of signal-intensity alterations as caused by blood flow will be described in order to prevent errors in interpreting of NMR-Images. The results of flow-measurements with the 0.35 Tesla imaging system in Berlin will also be presented. Finally, clinical examples of flow influence on images will be discussed.