Influence of imaging parameters on high-intensity cerebrospinal fluid artifacts in fast-FLAIR MR imaging

BACKGROUND AND PURPOSE: High-intensity CSF artifacts at the basal cisterns on MR images are often seen when a fast fluid-attenuated inversion recovery (FLAIR) technique is used. We investigated the influences of four optional fast-FLAIR sequence parameters on the high-intensity CSF artifacts. METHODS: A total of 377 patients (age range, 1 week to 91 years; mean 40.6 years; 186 female, 191 male) were examined with axial fast-FLAIR images obtained (TR/TEeff/TI, 8800/133/2200) with a 1.5-T system during 6 months. The effects of the optional addition of inferior inflow saturation (thickness, 80 mm), section flow compensation, and tailored radiofrequency (TRF) pulses, plus the choice of interleaving acquisition factors of 2 or 3, were evaluated for the presence of high-intensity CSF artifacts on the fast-FLAIR images. Two radiologists independently reviewed the fast-FLAIR images in 76 patients; afterward, a single observer reviewed the remainder of the images. RESULTS: The interobserver agreement rate in 76 cases was more than 90%. The use of TRF and/or three interleaving acquisitions resulted in a substantial reduction in the incidence of high-intensity CSF artifacts from about 80% to 40% (P <.05, two-sample two-sided Z test). Inferior inflow saturation and section flow compensation did not significantly improve image quality (P > .05). The results were consistent with the image quality ranking obtained in five healthy volunteers. CONCLUSION: The appropriate choice of sequence parameters in fast-FLAIR imaging reduces the incidence of high-intensity CSF artifacts that are frequently encountered in the presence of rapid CSF flow.