Diffusion-tensor MR Imaging of the Human Brain with Gradient- and Spin-echo Readout: Technical Note
Ryuta Itoha,
Elias R. Melhem
,a and
Paul J.M. Folkersa
a From the Department of Radiology and Radiological Sciences (R.I., E.R.M.), The Johns Hopkins Medical Institutions, Baltimore, MD, and the Philips Medical System (P.J.M.F.), Best, The Netherlands.
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FIG 1. Images of a 35-year-old male volunteer.
A, Axial 4-GRASE b0 image, 4615/119/4 (TR/TEeff/excitations), obtained at the level of the temporal lobe base.
B, Single-shot spin-echo echo-planar b0 image, 5538/96/4, obtained at the level of the temporal lobe base.
C, Thresholded binary image generated from single-shot spin-echo echo-planar b0 image.
D, Difference image obtained by subtracting the binary maps of the 4-GRASE b0 images from the binary map of the T1-weighted spin-echo image.
E, Difference image obtained by subtracting the binary maps of the single-shot spin-echo echo-planar b0 images from the binary map of the T1-weighted spin-echo image. Note that the distortion index (number of pixels in the black zone) is greater for the subtracted image E than D, which is the result of more severe distortion in the single-shot spin-echo echo-planar b0 images, as shown by thick bands of signal loss (*) and signal hyperintensity (arrows).
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FIG2.Images of a 34-year-old male volunteer.
A, Axial single-shot spin-echo echo-planar 3429/96/4 MR image, obtained at the level of the basal ganglia. The single-shot spin-echo echo-planar diffusion-weighted MR image and the corresponding maps (B, C) show a greater degree of distortion of the frontal lobes around the frontal sinuses and a higher SNR than do the 4-GRASE diffusion-weighted MR image and maps (D, E, F).
B, Corresponding ADCi map.
C, Corresponding FA map.
D, 4-GRASE 4286/119/4 diffusion-weighted image, obtained at the level of the basal ganglia.
E, Corresponding ADCi map.
F, Corresponding FA map.
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FIG 3. Images of a 34-year-old male volunteer (same volunteer as in fig 2).
A, Axial 4-GRASE 4286/119/4 image, obtained at the level of the lateral ventricle body.
B, Corresponding ADCi map.
C, Corresponding FA map.
D, 10-GRASE 4286/119/10 diffusion-weighted MR image, obtained at the level of the lateral ventricle body. As expected, the 10-GRASE diffusion-weighted MR image and maps (D, E, F) show higher SNR than the 4-GRASE diffusion-weighted MR image and maps (A, B, C) at the expense of longer acquisition time.
E, Corresponding ADCi map.
F, Corresponding FA map.
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