The Direction of Flow and Phase-encoding Schemes Effects on Signal Intensity in T1-weighted Inversion Recovery TurboFLASH Images.

Background: It is needed to minimize the effect of flow direction on the desired area, such as arterial input function (AIF) in magnetic resonance imaging (MRI).

Objective: The current study aimed to investigate the effect of flow direction on different velocities (0-80.39 cm/s) for the strength of the signal intensity (SI) at the linear phase-encoding (LPE) and the center out phase-encoding (COPE) schemes and to recommend the best flow direction in a selected slice and scheme for absolute perfusion measurement by inversion recovery T1-weighted turbo fast low-angle shot (TurboFLASH) MR images.

Material and methods: In this experimental study, the flow rates were measured using a flow phantom, and the signal intensity (SI) was measured at the two opposite flow directions in the Z-axis perpendicular to the coronal image at a concentration of 0.8 mmol/L of gadolinium-diethylenetriaminepantaacetic acid (Gd-DTPA) by using the LPE and COPE schemes.

Results: The increase in velocity along with the growth in SI and inflow affected the use of LPE and COPE acquisitions in both directions. The velocity of the arterial input function is needed to calculate the inflow correction factor by using two schemes in two opposite flow directions to investigate perfusion.

Conclusion: The COPE scheme was better than the LPE scheme in measuring perfusion since the velocity and direction of blood flow affect SI less.