[Pulsatile echography (ultrasonic cerebral tomosphygmography) in carotid and vertebral pathology. Surgical applications].

Ultrasonographic cerebral tomosphygmography (U.C.T.S.) is a method for determining cerebral pulsatility by centimeter-thick sections. The prototype uses a 2 MHz ultrasound wave emitted in the direction of cerebral structures. The reflected wave is captured by centimeter-thick sections, the mean determined and a pulsatile index defined. This index varies according to the regions studied (cortico-subcortical, superficial sylvian, deep sylvian and vertebrobasilar). Physiologic pulsatility was determined from a series of 150 healthy subjects. This technique was used to evaluate effects of carotid and vertebral circulation revascularization in 21 patients. Findings showed lack of relation between anatomic lesion and cerebral pulsatility, absence of significant modification of the index after release of carotid occlusion except when postoperative thrombosis occurred, and heterogeneous individual behavior after revascularization distinguishing subgroups of indifferent (40%), improved (27%), hyperpulsatile (27%) and worsened (13%) subjects. Two patients presented worsening on the contralateral side compatible with a steal syndrome. Results suggest that U.C.T.S. is a promising method of preoperative investigation and postoperative surveillance of carotid artery stenosis.