Interactive Transcript
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Let's contrast that previous case from this child who
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also has a fat containing lesion in the spinal canal.
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We have T1-weighted scan, T2-weighted scan,
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and STIR imaging of the lumbar spine.
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So the lesion is bright in signal intensity
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on the T1-weighted scan simulating fat,
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ad on the STIR imaging where the fat has been suppressed,
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the lesion suppresses. So, we know it's a lipoma.
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even if we didn't have the STIR imaging, however,
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we would have a good indication that this is fat
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containing as opposed to high protein or melanin
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containing or enhancement by virtue of the chemical
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shift artifact that I described previously,
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at the border of the lesion with this darker rim as a
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frequency shift associated with the different
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frequency at which fat precesses versus CSF.
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So we have a lipoma.
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This one is anteriorly located.
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But importantly,
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this patient also has a low lying spinal cord, right?
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So we have the...
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we're at, maybe this is five, and this is L4,
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and this is L3, L2, L1.
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So you have cord tethering with this lipoma.
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If we go further and count the number of sacral
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segments, we note that there's an S1, an S2, and S3,
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and then we sort of kind of lose the development
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of the lower sacrum and coccyx.
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So this patient's congenital malformation is associated
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with this lipoma and the tethered cord.
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Let's just scroll a little bit more from side to side.
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You want to look for whether or not there are posterior
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elements that are intact to also identify whether
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there is spinal dysraphism. In this case,
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the posterior elements are intact,
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but the lower sacrum and coccyx
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have not been well developed.
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You also want to look in the subcutaneous fat.
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And this sometimes requires windowing at different
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levels to see whether or not there is a tract leading
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from the skin surface to this lipoma
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or to the end of the spinal cord.
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We note also that there is fat down here, which is
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suppressing more posteriorly. So in this area
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where the sacrum has not been well developed,
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you also have prominence to the posterior epidural fat,
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which is separate from the lipoma more anteriorly.
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