The first attempt at radioisotopic evaluation of the integrity of the nose-brain barrier.

The first attempt at radioisotopic assessment of the integrity of the nose-brain barrier was performed on an anosmic patient by spraying an aliquot of a mixture of 99mTc-DTPA and hyaluronidase onto the olfactory mucosa with the patient's head positioned vertically and subsequently measuring the cerebral radioactivity. A significant rise in cerebral radioactivity was observed 5 minutes after introduction of the radioisotope. This simple technique will aid in assessing olfactory impairment from selected etiologies and also in testing the integrity of the nose-brain barrier. In view of the study of diseases such as viral encephalitis and Alzheimer's disease, the clinical implications of this method cannot be overemphasized. This principle may also facilitate developing novel pharmaceuticals for some brain diseases.