Figure 3: DCE-MRI region of interest (ROI) analysis in the centrum semiovale (CSO) of a 73-year-old healthy female. (a) Axial -weighted (turboFLASH) images were collected on a Siemens 7 T system with 8-channel phased array transmit/receive head coil; selected ROI shown in white. (b) Plot of pre-post contrast () versus time. Images were collected immediately preceding two 0.05 mmol/kg bolus injections of gadoteridol and every 2.5 seconds over the next 175 sec. values were calculated at each time point by fitting the signal intensity curves to a standard two-parameter single exponential inversion recovery equation . (c) plotted as a function of . Changes in the blood signal, , were determined from an ROI placed entirely in the sagittal sinus. The solid line represents the best fit of the data to (3). Resultant estimates of , and are also shown.