MRI OF THE INCISURAL PLANE - ASSESSMENT OF NORMAL BRAIN-STEM POSITIONBY AGE AND TRANSTENTORIAL BRAIN-STEM SHIFT IN DISEASE

The standardization on MRI of an anatomic plane passing through the te ctum of the midbrain based on fixed landmarks allows assessment of the position of the brain stem during development and in normal adulthood , and comparison with its position in disease states. The level of the tectum relative to this incisural plane changes during normal cranial growth as well as in the presence of masses, frank brain stem herniat ion correlating with altered consciousness.