Brain Tumor CT Scan

Drawing of the effects of an extra axial mass on the brain
and a CT scan showing an ISODENSE mass. Using the principles we
learnt earlier, can you detect asymmetry in the two halves of the scan?
Can you make out where the tumour is? (Note = it is isodense with brain).
Start first by working out which side has the abnormality and then look
for the abnormality. Yes, you read correctly. First decide which side is
abnormal, then look for the abnormality. ‘(And this is the clue: whenever
there is a pressure effect or mass effect, the CSF is the first thing
to be displaced. If you think back in this chapter, we started with what
distorts the sulci and progressed to what will distort the sulci and gyri.
So in a CT scan, a general rule of thumb is that the half with the least
amount of CSF is likely to be abnormal. That goes without saying if the
CSF is the most easily displaced component of the cranium, the lesion
is likely to start displacing CSF from its immediate vicinity! So the left
with the large dark CSF space is the normal side and the right without
any CSF space is abnormal. Now can you make out the abnormality?
It is isodense; for instance, same density as the brain so you will need
your skills at pattern analysis to identify the abnormality.

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