Re: MRI and gadolinium

["Ed Schweber" <edschweb@ix.netcom.com>]

Ed Schweber (edschweb@ix.netcom.com)
Physics Teacher at The Solomon Schechter Day School, West Orange, NJ
To obtain free resources for creative physics teachers visit:
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-----Original Message-----
From: Delphi High School <pmason@wvec.k12.in.us>
To: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
Cc: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
Date: Wednesday, August 19, 1998 12:09 AM
Subject: MRI and gadolinium

Patti Mason wrote (in part)


> I went to an orthopedic surgeon today about chronic back pain and
> as expected he ordered an MRI of my spine. However, unlike other
> MRI's I have had ordered, he specifically wrote with gadolinium on
> the Rx form.

Hi:

   I have had brain MRIs following a bicycle accident. The gadolinium is
injected. The radiologist's report indicated that there was no abnormal
gadolinium enhancement.

   I suspect that gadolinium has a strong resonance at MRI frequencies and
that it might be especially absorbed by certain types of pathological
tissues thereby making it useful for diagonosis.

   As long as wer're talking about MRIs -perhaps another question. I have
heard both that the image formation is based on the amount of EM radiation
absorbed (as with an x-ray) and also that the image is formed by the
re-emitted radiation after the external pulse ends. Does anyone know which
is the case? Thanks.

Ed Schweber