The Efficacy of Calculation of Mean Transit Time without Using Arterial Input Function : A Trial of Classification of Perfusion Reserve Capacity using Perfusion MRI

Arterial input function (AIF) has been used for quantitative evaluation of perfusion MRI (PWI) parameters, but this cannot be used in most general facilities. We have calculated mean transit time (MTT) simply by subtracting arrival time from mean time to enhance (MTE). In 43 patients with occlusive cerebrovascular disease, in order to evaluate the efficacy of this simple method for MTT measurement, we calculated PWI parameters (MTT, MTE, maximum slope of increase, and negative enhancement integral) semi-quantitatively without using AIF, and compared these parameters with cerebral blood flow (CBF) and cerebrovascular reserve (CVR) evaluated by Xe-CT. PWI parameters and CBF were represented as a ratio between affected-and non-affected-sides. Among the PWI parameters, MTT ratio showed the strongest correlations with both CBF ratio and CVR (p