Abstract #1533

Wang Z, Thornton R, Jones J

In dynamic susceptibility contrast MRI, the shape of the arterial input function (AIF) is commonly obtained in the near vicinity of the middle cerebral artery (MCA). However, the tissue regions where the AIF is sampled also have significant perfusion, which causes T2* changes. We investigate whether correction of this effect will introduce significant changes in the measurement of the AIF. In the correction procedure, subtracted from the &[Delta]R2* sampled in the immediate vicinity of the MCA was the &[Delta]R2* sampled in a nearby region of gray matter away from the MCA. We demonstrate that in the brain, this correction of &[Delta]R2* due to tissue perfusion leads to a narrower width of the AIF curve, and the peak of the AIF also moved to a slightly earlier time relative to the time of arrival. Using the corrected AIF, longer mean transit times were obtained from both gray and white matter areas.