The effect of carotid endarterectomy on cerebral blood flow and cerebral blood volume studied by SPECT.

The aim of our work was to study the state of regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in patients with different degree of carotid stenosis after CE. Thirty six patients with carotid stenosis aged 46-65 years (mean age 55 years) were studied. In all the patients before and one month after carotid endarterectomy (CE) single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO, Ceretec, Amersham) and SPECT with labelled in vivo 99mTc-red blood cells (99mTc-RBC) were carried out. According to the results of scintigraphic studies the regional cerebral blood flow (rCBF, ml/min/100g), the volume of hypoperfusion (Vhypoperf., sm3), the stroke volume (SV, sm3), the interhemispheric ratio of rCBF (IRrCBF) and the regional cerebral blood volume (rCBV, ml/100g) were calculated. CE leads to the bilateral increase of cerebral perfusion especially at the side of more expressed damage putting away interhemisphere asymmetry of rCBF. After CE the regression of SV and Vhypoperf were revealed. In asymptomatic disease patients with monolateral stenosis of carotid arteries rCBF reaches normal values and regions of hypoperfusion are not revealed. Surgical recanalization of carotid arteries causes expressed changes of scintigraphic parameters of rCBV: normalization of initially increased values of rCBV in patients with asymptomatic development of stenosed atherosclerosis of carotid arteries and subsequent increase of rCBV in comparison with preoperative level in patients who underwent acute stroke with neurological deficit and patients with poor clinical signs and multiple damage of both internal carotid arteries.