[Safety aspects in MR imaging].

With the growing number of Magnetic Resonance Systems in operation in clinical practice, safety aspects gain increasing importance. Therefore, it is necessary to evaluate possible risks and effects on human health. After an introduction to the basic principles and techniques involved, the various effects on biological systems and especially the human organism caused by the static magnetic field, the alternating magnetic fields and the high frequency fields required are described on the basis of current literature and partially also on our own experience.

[Depiction of evoked regional brain activity using magnetic resonance tomography].

After brief summary of the various parameters determining contrast behaviour in diagnostic magnetic resonance imaging, special attention is paid to recent developments in its application to the study of brain perfusion and oxygenation. With and without extrinsic contrast media, it is now possible to image regional tissue perfusion and brain oxygenation and thus the evoked activation of regions of the brain with a high spatial resolution of about 1 mm and a temporal resolution of about 50 ms. The blood oxygenation dependent magnetic properties of hemoglobin are used as sensitive endogenous indicators of the oxygenation state of blood.

[Early clinical experience with nuclear magnetic resonance (author's transl)].

Previous work on adults with carcinomas, benign polyps, postoperative changes or inflammatory or radiation induced swellings in the facial skeleton has shown that it is possible to demonstrate the local anatomy, and particularly the orbits and sinuses without subjecting the patients to radiation. Differentiation between fat, oedema and malignant tissue appears to be possible, as has been demonstrated by our early cases. Early attempts at examining the trunk could only be carried out in infants.

[Nuclear magnetic resonance tomography].

Imaging methods based on nuclear magnetic resonance allow the production of sectional images of the human body without ionizing radiation. It is possible to measure the density and relaxation times of the water protons in body fluids or tissue. This allows not only to obtain morphological information but also to get some insight into the spatial distribution of physiological data.