Slice overlap/interference
Why are there dark bands over the lumbar spine?
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The dark bands you see are signal dropout due to the use of multiple overlapping oblique slices. Protons in the overlapped areas receive double, triple, or higher levels of RF-irradiation than those in single slices elsewhere. As a result, their steady-state magnetization is reduced through saturation.
The solution to this problem is simply not to overlap the slices in a single acquisition, or if they must be overlapped, to do so in separate acquisitions. In other words, obtain the oblique images in concatenated (rather than sequential) acquisition mode. |
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References
Simmons A, Tofts PS, Barker GJ, Arridge SR. Sources of intensity nonuniformity in spin echo images at 1.5T. Magn Reson Med 1994: 32:121-128
Simmons A, Tofts PS, Barker GJ, Arridge SR. Sources of intensity nonuniformity in spin echo images at 1.5T. Magn Reson Med 1994: 32:121-128
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