Published ahead of print on April 15, 2009
doi: 10.3174/ajnr.A1514
Normal Findings on Brain Fluid-Attenuated Inversion Recovery MR Images at 3T
M. Neemaa,
Z.D. Gussa,
J.M. Stankiewicza,
A. Aroraa,
B.C. Healya and
R. Bakshia,b
a Departments of Neurology, Brigham and Women's Hospital, Laboratory for Neuroimaging Research, Partners Multiple Sclerosis Center, Harvard Medical School, Boston, Mass
b Radiology, Brigham and Women's Hospital, Laboratory for Neuroimaging Research, Partners Multiple Sclerosis Center, Harvard Medical School, Boston, Mass
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Fig 1. Comparison of 1.5T and 3T axial 2D FLAIR MR images in a 50-year-old healthy woman. Images of the same regions with equivalent pulse sequences display the improved sensitivity in discrete foci–detecting capabilities (arrows) and tissue resolution (tissue-CSF distinction) of the 3T scanner. Representative images are shown. In total, FLAIR showed 11 discrete foci in the whole brain (total brain volume of discrete hyperintense foci = 310 mm3) at 1.5T and 26 discrete foci (total volume = 521 mm3) at 3T. The 1.5T FLAIR scan (A) shows less prominent number and conspicuousness of discrete foci than seen at 3T (B). The arrows show some of the differences between the images. Note that anterior capping is present on both platforms. However, a striking diffuse posterior white matter hyperintensity is present only at 3T, part of which is related to posterior capping.
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Fig 2. A and B, Graphs show a larger hyperintense foci number (A, P = .0066) and volume (B, P = .0054) on 3T FLAIR scans than on 1.5T FLAIR scans. Histograms indicate mean; bars, standard error of the mean. Asterisks indicate a significant difference (P < .05) when comparing 1.5T with 3T in the 15 subjects scanned on both platforms. C, Distribution of total brain hyperintense foci number for each subject; squares indicate individual cases. See also Table 2.
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Fig 3. Relationship between total brain FLAIR hyperintense foci volume/number and age at 1.5 and 3T. Scatterplots show the relationship between total FLAIR hyperintense foci volume (A and B) or number (C and D) and age on 1.5 and 3T scans in the healthy volunteers (n = 15). Each square represents a subject. Total FLAIR hyperintense foci volume (r = 0.70, P = .004) and number (r = 0.69, P = .005) at 1.5T and total FLAIR hyperintense foci volume (r = 0.74, P = .0001) and number (r = 0.72, P = .0002) at 3T show a significant correlation with age. See also Table 4.
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Fig 4. Comparison of 1.5T and 3T FLAIR images from healthy adult subjects. A and B, Representative paired axial FLAIR images of a 47-year-old woman. Both platforms show a bright periventricular lining of the lateral ventricles (arrows) and septum pellucidum hyperintensity (arrowhead). Also note the prominent hyperintense CSF flow artifacts in the frontal horn of the left lateral ventricle (arrows). C and D, Representative paired axial FLAIR images of a 50-year-old woman. Both platforms show bilateral corticospinal tract hyperintensity (arrows). E–H, Representative paired axial FLAIR images of a 53-year-old man. Both platforms show hyperintensities (arrows) of the third ventricular lining (E and F), cerebral aqueduct lining (E and F), and within the fourth ventricle due to CSF flow (G and H). Ventricular CSF pulsation artifacts are seen to a similar degree between platforms, but only 3T FLAIR shows diffuse posterior parenchymal white matter hyperintensity (F, arrowhead).
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