Inflow Effect Correction in Perfusion Measurement of Normal Subjects with T1-Weighted Images Using Inversion Recovery Sequences

Background/Objective: A dynamic contrast-enhanced T1 technique has been applied for calculating cerebral blood flow (CBF) with MRI. Previous studies have shown that the CBF calculated from T1 techniques was lower than the expected CBF. One cause could be the change in MRI signal intensity due to blood flowing into the measurement slice. The aims of this paper were: 1. To quantify the effects of inflow on perfusion measurements using a phantom. 2. To apply a simple inflow correction to perfusion measurements taken from 11 healthy subjects. Patients and Methods: A flow phantom was designed to produce different velocities covering the velocity range of small vessels and big arteries. The inflow effects were measured in the phantom. After the contrast administration for healthy subjects, CBF was calculated based on T1 technique. Results: The inflow correction factor for the common carotid artery velocity and capillary level was calculated by the phantom as 1.23 and 1, respectively. The average value of CBF on the middle cerebral artery (MCA) grey matter territory of 11 healthy volunteers without any correction was 43.0 mL/100 g/min. Conclusion: For measuring the absolute CBF, the inflow correction factor for the arterial input function and tissue should be known. After applying the inflow correction factors, the absolute CBF may be calculated as 52.9 mL/100 g/min. This value is in good agreement with those in the PET literature.