O contributo da tomografia computorizada de perfusão no acidente vascular cerebral

Multisection computed tomography (MSCT) was introduced in 1998 and improved neuroimaging quality, in particular concerning acute stroke. Previously, non-enhanced CT was used not only to detect early stroke signs, but also to exclude hemorrhage and non-vascular pathology responsible for the acute neurological deficit. Nowadays, using Perfusion CT (PCT) it is possible to obtain a functional study of the cerebral hemodinamics after injection of a fast bolus of contrast. Multi-voxel analysis of the time-attenuation curves delivers colour maps of Cerebral Blood Flow (CBF), Mean Time Transit (MTT) and Cerebral Blood Flow (CBF). Based on specific patterns of hemodinamic changes it is possible to differentiate between irreversible and reversible brain damage--"tissue at risk", which is essential for choosing an appropriate therapy. The authors will discuss data acquisition, post-processing and image interpretation and analysis starting from two clinical examples.