In Vivo Measurement of Blood Transit Time in Rat Brain using the Saturation Recovery-T1app Imaging Method

Xiao Wang¹, Xiao-Hong Zhu¹, Yi Zhang¹, Wei Chen¹

A two-phase spin model was proposed for quantifying the dynamic magnetization change of the saturation recovery T1app (SR-T1app) measurement, and determining CBF and blood transit time, which is a physiologically and pathologically important parameter and sensitive to the status of hemodynamic impairment in cerebrovascular disorders, for example, in stroke. The estimated transit times in the rat brain using SR-T1app measurement and the two-phase spin model showed excellent consistency and reproducibility under both normocapnia (28016 ms) and mild hypercapnia (21810 ms) conditions, and they are in coincidence with literature reports ranged from 100 to 400 ms. Therefore, the new SR-T1app method not only offers a noninvasive and simple tool for mapping rat brain CBF change, but also provides a promising way for estimating brain blood transit delay in vivo.