Abstract:
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Purpose: To compare 3-T and 1.5-T images for demonstrating brain iron in the
form of hypointensity in the globus pallidus.
Methods and Materials: 16 subjects underwent MRI with 1.5 T and 3 T field
strength using T2-weighted fast spin-echo images. Region of Interest (ROI)
measurements were carried out through the globus pallidus bilaterally, the
thalamus (gray), the supratentorial white matter (white) and the air (noise).
Contrast to noise was determined with reference to the gray matter (as
reference tissue) and again with white matter. Subjective visual comparisons
were also made.
Results: The mean C/N for the lesion compared with gray matter was 3.85 at 1.5
T and 8.01 at 3.0 T. This represented an increase of 134%. The mean C/N for the
lesion compared with white matter was 1.48 at 1.5 T and 6.5 at 3.0 T. This
represented an increase of 288%. Combining the gray matter background C/N's and
the white matter background C/N's, the mean C/N was 198% superior with 3-T.
Subjective visual comparisons confirmed improved conspicuity of the globus
pallidus with 3-T by virtue of the accentuated hypointensity.
Conclusion: 3-T MRI is superior to 1.5-T for the visualization of the globus
pallidus presumably due to the effect of iron. The 3-fold improvement in C/N is
correlates well with theoretical models wherein magnetic susceptibility is
proportional to the square of the field strength. It is suspected that this
improvement could also apply to other foci of iron in the brain.
Questions about this event email: WOLANSLJ@UMDNJ.EDU
Wolansky MD, L,
Comparison of 3 T and 1.5 T MRI for the Demonstration of Globus Pallidus Iron. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3108813.html
