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Anyone Familiar with CT scans?

  1. Mar 14, 2005 #1
    The following CT scan of Terri Schiavo purportedly suggests that her cerebral cortex consisted entirely of fluid at the time the image was made many years ago.

    http://www.miami.edu/ethics2/schiavo/CT scan.png

    I'm skeptical of the claim because the image is too symmetrical. An injury condition would be more likely to produce damage without a pattern. Also there is the problem of getting the cellular debris out of the area and replacing it with fluid only. I'm also skeptical of reliance on a CT scan which isn't particularly reliable on soft tissue.
     
  2. jcsd
  3. Mar 14, 2005 #2
    CT scanning is very reliable and useful for soft tissue imaging. Otherwise it wouldn't be as widely used as it is. CT scanners were originally developed for brain scanning 30 years ago, and even then produced very good images showing differences between the different types of tissue in the brain. CT scanners today are several orders of magnitude better than those early scanners.

    Although I'm not a radiologist (just a medical physicist), the first thing to note is that the image appears to be just a photograph of an imageon a monitor (probably taken at the acquisition console. Not exactly what I would call a diagnostic image.

    Secondly, the ventricles are significantly enlarged compared to normal which would put pressure on and displace normal brain tissue. The colour of the material around the lighter grey stuff is about the same colour (and therefore density) as the fluid in the ventricles, which would suggest the purported conclusion.

    I cannot say for sure what the white speck in the left ventricle is without seeing more images, but my first guess would be a contrast filled blood vessel.

    Thirdly, it's very difficult to make any kind of meaningful diagnosis from just one CT image. I doubt you'd find a radiologist anywhere who would give you any kind of proper diagnosis from just one image. Not all brain injuries have to be asymmetric. The symmetry (or asymmetry) of any kind of brain injury would depend entirely on what type of injury it is.
     
    Last edited: Mar 14, 2005
  4. Mar 14, 2005 #3
    she didn't have any trauma to the brain...the liquid began collecting after her heart stopped briefly, cutting off oxygen to the brain .The cause, potassium imbalance brought on by an eating disorder.
     
  5. Mar 14, 2005 #4

    Moonbear

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    The ventricles (you're seeing the lateral ventricles in this image; that somewhat butterfly-shaped structure in the center) are HUGE!!! Even looking at one image tells me there is a hydrocephalic condition here. One wouldn't make a definitive diagnosis from a single image, but that one appears pretty strikingly abnormal; a full series of images would be more convincing, as well as to see how extensive the hydrocephaly is.

    It's not a matter of removing cellular debris and replacing it with fluid, what it looks like is an overaccumulation of CSF. In the short term, that would compress the brain tissue, and in the long term, if that pressure was not relieved, the compressed tissue would die off. Injuries come in many forms. This sort of pattern of hydrocephaly could have many causes, including blockage of the aqueducts between ventricles or to the spinal cord, or overproduction of CSF or excessive leakage of it due to inflammation of the brain.

    The CT scan won't necessarily show you the focal point of injury unless you're injecting a radioopaque dye and looking for problems in blood flow, but it can show gross abnormalities, such as the enlargement of the ventricles in that image.
     
  6. Mar 14, 2005 #5

    Moonbear

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    For comparison with a scan from a normal brain:
    http://www.med.harvard.edu:80/AANLIB/cases/caseM/mr1_t/033.html

    This is an MRI scan, which shows the ventricles in white. You can use the arrow up and down to compare to different levels to see the ventricles are much smaller in a normal person. I've linked to a level that is somewhat comparable to what I think the image shown for Terri is (though I can't be certain exactly what level it was from a single image).
     
  7. Mar 15, 2005 #6

    DocToxyn

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    Wow, those are large ventricles. I have witnessed the effects of developmental hydrocephaly as a background occurrence in mouse colonies. When this happens during development it is considered a disruption-type of alteration since the accumulation of CSF pushes or disrupts tissues that are already formed and established. The examples of this I have seen were extreme with a majority of the cranial cavity taken up by ventricle and only a thin (~2mm) layer of brain remaining along the inside of the skull. Suprisingly the mouse appeared fairly normal and was only spotted due to the rather large head as compared to his litter mates. Not having done any behavioral testing on this individual I couldn't tell you about higher brain function, but he had survived well past weaning and was quite normal in most aspects. It's amazing what the body can cope with during development.

    I'm not as familiar with this condition in humans, especially in an adult onset case such as this. From what I can gather on the web, she had a heart attack that cut off circulation to the brain, the resulting hypoxia lead to brain damage and eventual atrophy of the tissue which was then replaced by CSF. This might be considered a normal pressure hydrocephaly, or brain atrophy-related ventriculomegaly, that didn't cause the damage but is a result of it.
     
  8. Mar 15, 2005 #7
    Thanks for the info and the link.
     
  9. Mar 31, 2005 #8

    Moonbear

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    I just want to update that this is not likely to be a CT scan of Terri Schiavo's brain. On a tip-off from another site, I took the image to photoshop and flipped it so I could read the text. This image is dated July 2, 2002, not 1996, although the date of birth of the subject is the same as Terri's DOB (Dec 3, 1963).

    Edit: I just found out there was a scan done in 2002, so now I'm not sure again. Anyway, it's at least not the 1996 scan. Whether or not it's the 2002 scan of Terri's brain, I have no way to verify.
     
    Last edited: Mar 31, 2005
  10. Apr 1, 2005 #9

    iansmith

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    MSNBC is showing the 2002 scan
    http://www.msnbc.msn.com/id/7328639/ (this link was posted by evo in the terry schiavo thread in the politics forum)

    It is exactly the same scan shown by reasonmclucus.
     
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