CHICAGO — Perfusion computed tomography is a useful modality in the detection of regional brain perfusion deficits in patients with severe internal carotid artery stenosis, Dr. Agnieszka Trojanowska during a poster presentation at the annual meeting of the Radiological Society of North America.
CT perfusion imaging revealed that internal carotid artery stenosis in most cases was associated with brain perfusion deficits ipsilaterally to the stenotic site, and that hypoperfusion tended to improve considerably after stent placement, said Dr. Trojanowska, who also has a PhD.
In the study, 74 patients with symptomatic internal carotid artery stenosis of more than 70% were evaluated with CT perfusion imaging, on average, 70 hours before carotid stent placement and then 3 days and 6 months after stent placement. The protocol included a non-contrast enhanced transaxial CT of the brain with a 5-mm slice and 5-mm slope and dynamic CT perfusion imaging during administration of 50 mL of contrast medium at 4 mL/s with a 5-second delay.
Before stent placement with embolic protection devices, 84% of patients had perfusion deficits ipsilaterally to the stenotic site. Three days after stent placement, 30% of patients had perfusion deficits, and at 6 months, the deficits had diminished to 6%, said Dr. Trojanowska of the Medical University of Lublin (Poland).
A marked elongation of the mean transit time (6.2–6.8 seconds) was noted at the stenotic site, together with decreased values of cerebral blood flow (40–46 mL/100 g per min) and slightly increased cerebral blood volume (3.2 mL/100 g).