Influence of subarachnoid structures on transmeningeal ultrasonic propagation

Abstract

The previously observed frequency dependence of the ultrasonic threshold dose, for production of irreversible lesions in mammalian brain, is ascribed to the brain meninges. The collagenous trabeculae of the subarachnoid space, interposed between the arachnoid and the pia mater, are considered responsible by virtue of the increased elastic moduli associated with their structural supporting role. A plane three media model provides acoustical parameters of these anatomic structures. The method provides the frequency-independent lesion-threshold function It1/2=200 W/cm2 sec−1/2.Subject Classification: [43]80.40.[43]80.20