Just for fun, then I got to get to work -- here is another link. This
one says you would not use a CAT scan to assess the amount of brain
damage, you would use an MRI which, correct me if I am wrong, this
woman has not had.

Dana

http://www.birf.info/artman/publish/Ed-Brainimg_doc.shtml



Medical Conditions & Interventions 
--------------------------------------------------------------------------------

Brain Imaging: CAT Scan and MRI
By Florence C. Barnett, MD
Sep 14, 2003, 17:52

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In treating traumatic brain injury, viewing images of the brain,
particularly injured areas, is crucial to the neurosurgeon for
planning treatment.  Images of the brain may be obtained through
computerized tomography (CT) or magnetic resonance imaging (MRI). 
These techniques permit imaging of the brain for both diagnosis of
injury and choosing therapeutic interventions.

 

CT scanning uses a series of x-rays of the head taken from many
different directions.  The amount of radiation that passes through the
head in each direction is measured and recorded.  Many such
measurements are taken from different directions at each level of the
brain, from the top to the bottom.  A computer program uses a set of
algebraic equations to estimate how much x-ray is absorbed in a small
area within a cross section of the brain.  In this way,
cross-sectional images are created at different levels throughout the
brain.

 

The CT scan is useful for quickly viewing brain injuries.  The CT scan
can localize epidural blood clots outside the lining of the brain,
subdural blood clots inside the lining of the brain, and hemorrhages
within brain tissue.  The CT scan allows Neurosurgeons to assess the
effects of bleeding on the brain, such as pressure moving sensitive
brain tissue or decreasing blood flow to the brain.  The CT scan also
allows the Neurosurgeon to evaluate for swelling due to both tissue
damage and dilated blood vessels within the brain.  These conditions
increase brain pressure and secondarily may decrease blood flow in the
brain.  These images, combined with physical examination, allow the
Neurosurgeon to plan interventions, including removal of blood clots,
controlling swelling, and monitoring brain pressure.

 

CT scans can also be used to assess the size of the ventricles (the
location where spinal fluid is produced) within the brain.  If spinal
fluid flow is blocked, the ventricles may become enlarged, a condition
called hydrocephalus.  In another condition, the ventricles may
enlarge due to gradual loss of surrounding brain tissue, a condition
called hydrocephalus ex vacuo.  Because there is a fixed amount of
space within the skull, if brain tissue is lost, then the ventricles
enlarge to fill this space.  This condition, unlike pressure
hydrocephalus, does not require a shunting procedure to remove spinal
fluid.

 

MRI scanning, like CT, also uses computer programs to produce cross
sectional images of the brain.  Unlike CT scanning, the MRI scan uses
a high intensity magnetic field to magnetically align hydrogen atoms
within molecules in the brain.  These hydrogen atoms then produce
radio signals, which are located and measured, and then used by the
computer program to produce cross sectional images.  MRI scans can
produce cross sectional images in any direction from top to bottom, as
in CT scanning, from side to side, or from the front to the back of
the head.  MRI scans have a higher resolution compared to CT scans,
and can show differences in brain tissues based on their fat and water
content.  Hydrogen in higher fat content areas, produces a radio
signal more quickly than hydrogen in higher water content areas.  The
MRI scan takes advantage of this property to produce images of
different structures in the brain.  This allows the MRI scan to
differentiate between gray and white matter within the brain.  MRI
scanning requires the patient to remain motionless for up to 20
minutes; therefore, it may not be possible to obtain an MRI scan in
the early stages of a brain injury.  For this reason, MRI scanning is
often reserved for the latter stages of recovery.

 

After the patient is more stable, an MRI scan can be used to assess
the amount and location of brain injury.  This information is used to
plan treatments and therapies, and to predict recovery.

 

CT and MRI scans are powerful tools for assessing and treating brain
injury.  The choice of scan depends upon the urgency of the
information needed and ability of the subject to participate in the
scanning procedure.  For this reason, CT scans are often more used in
the early stages of recovery to assess for life threatening
conditions.  MRI scans are most useful in assessing the amount and
location of brain injury for planning therapies and predicting
recovery.



On Tue, 22 Mar 2005 10:12:53 -0800, Sam <[EMAIL PROTECTED]> wrote:
> Yeah, the asshole didn't respond to my post about the ct scan and his
> outdated 1996 report about how useless the ct scan is. But then went
> and diagnosed the scan himself :)
> 
> But then again he always forgets to respond when you prove him wrong.
> 
> 
> On Tue, 22 Mar 2005 11:01:05 -0700, Dana wrote:
> > well, give me credit at least for generally in facts and for being
> > willing to re-valuate my position.
> > But if I ever sounded like this while being this wrong, well hell, I
> > apologize. Ask me about my facts or something next time willya?
> >
> > Larry, speaking of acting like an ass, I notice you haven't responded
> > to the journal articles I posted last night. Peer-reviewed journals,
> > articles less than two years old. That (incidentally) say you are full
> > of it.
> >
> 
> 

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