Fluid Attenuated Inversion Recovery (FLAIR) Imaging of the Normal Brain: Comparisons between Under the Conditions of 3.0 Tesla and 1.5 Tesla

The aim of this study was to evaluate the differences in normal brain MRI findings between under 3.0 Tesla (T) and 1.5T MRI conditions with the use of the fluid attenuated inversion recovery (FLAIR) sequences. Eleven normal adults underwent imaging with the use of the FLAIR sequences on both 1.5T and 3.0T scanners. Two neuroradiologists compared the signal intensity (SI) of the centrum semiovale (CS), pulvinar thalami (PT) and normal iron deposit structures (IDSs) on the 3.0T and 1.5T FLAIR images, and they evaluated three MRI findings qualitatively: high SI of CS; low SI of PT; low SI of IDS. We also evaluated signal-to-noise ratios (SNRs) for the CS, PT, red nucleus and cerebellar dentate nucleus on the FLAIR images. Based on qualitative analyses, the 3.0T FLAIR images showed all three MRI findings for all cases. Low SI for the PT in seven cases (64%), high SI of the CS in one case (9%) and low SI of the cerebellar dentate nucleus in one case (9%) were visualized only on 3.0T FLAIR images. The mean SNRs of the PT, red nucleus and dentate nucleus in patients where 3.0T FLAIR imaging was performed were significantly lower as compared with the SNRs on 1.5T FLAIR images. The SNR of the CS was not significantly different between under the two magnetic field strengths (p > 0.05). We have demonstrated that normal, high and low SIs of the CS, PT and IDS on 3.0T FLAIR images were depicted more frequently and more prominently as compared with those on 1.5T FLAIR images in normal adult brains