Assessment of quantitative computed tomographic cerebral perfusion imagingwith (H2O)-O-15 positron emission tomography

Assessment of quantitative cerebral blood flow on a conventional fast CT ma chine without the use of specialized equipment may be valuable in the inves tigation of acute stroke and head injury. We aimed to compare a single slic e CT perfusion sequence with (H2O)-O-15 positron emission tomography using the sagittal sinus as an input function, a method that avoids unnecessary o rbital irradiation. Eight patients were studied, two patients with gliomas, and six with arteriovenous malformations. The dynamic CT perfusion sequenc e was performed by acquiring the same 10 mm slice 10 times over 30 sec duri ng a 50 mi bolus of intravenous contrast medium given at a rate of 7.5 ml s ec(-1) using a power injector. The CT perfusion studies were completed with out complication. Go-registration was sub-optimal in one patient Overall th e correlation between the two methodologies was encouraging with an a verag e r(2) value of 0.524 for individual analyses. When two patients with high flow arteriovenous malformations were excluded the average r(2) value incre ased to 0.640. The results of this CT perfusion methodology are encouraging . Having shown its feasibility further studies in conditions with lower rat es of cerebral blood now are warranted.