Cooperative patients can often keep still during a long examination of the brain provided that they are given cues about their position in space. In a U-shaped head support, the only movements likely are rotation in the sagittal or transverse planes. These can be detected by a nasal orientation device (NOD), simply a ring around the nose, close but not touching. Any unintentional movement is felt on the nose by the patient, who can return to the original (nontouching) position. With this device the patient can keep immobile to within approximately ±2 mm during long examinations. We have used the NOD to improve the quality of dynamic Gd-DTPA scanning for the measurement of blood-brain barrier permeability. The NOD can be of value in any neurological imaging procedure that is currently degraded by head movement. © 1990 Raven Press, Ltd., New York.
