Hi Andrew:

1. If you want "the opportunity to image a whole intact brain" with CT, 
why fix at all? What artifacts, if any, does fixation induce? Maybe 
fixation lowers contrast? Have you looked at a live mouse brain with CT? 
When CT is done on human brains, good contrast is obtained without 
fixation.
2. Osmium does not penetrate tissue well, 1 mm deep at best so even 
perfusing won't do much good.  And how do you know osmium will
increase the contrast with CT?

Geoff


Mr Andrew Tuck wrote:

>Hi 
>
>I was looking to use micro CT (computer tomography X ray) to examine
>newborn (P0) mice brains. The area we are most interested in is
>measuring the ventricle size in these animals. However we also want to
>look at the size and shape of other regions such as fiber tracts,
>etc..In the past this was done by doing 50um slices, putting these on
>slides, photographing the slices and using software to calculate the
>ventricle size.
>
>Using micro CT offers the opportunity to image a whole intact brain.
>However, in the first scan we performed of a fixed mouse brain you could
>see the shaodw outline of the brain but no internal detail. Osmium
>tetroxide is the heavy metal of choice to produce good X ray contrast,
>but does anyone know how you can perfuse an entire intact brain with it
>? I have not been able to find any protocols, or previous articles which
>have done this. Also I have read that osmium does not penetrate whole
>tissue very well. If this is the case, is there another fixative that
>would give good X ray contrast and penetrate the tissue well?
>
>
>Thanks
>
>Andrew Tuck
>Research Assistant
>Queensland Centre for Schizophrenia Research
>School of Biomedical Sciences 
>University of Queensland
>Australia
>Tel: 07 3346 2368
>
>_______________________________________________
>Histonet mailing list
>Histonet@lists.utsouthwestern.edu
>http://lists.utsouthwestern.edu/mailman/listinfo/histonet
>
>  
>


-- 
--
**********************************************
Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583; fax: -4029 
mcauliff@umdnj.edu
**********************************************



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