Fitting Andrews Mouse Brain at high resolution, higher B1 #13
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First attempt at fit (native method - as opposed to MCMC): 3 peaks:
---Peak 1--- ---Peak 2--- ---Peak 3--- |
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I think we're in business...
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what's peak 2 (the ultra-broad one)? firasm wrote:
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I think it's pixie-dust - there to make the whole thing fit better :-P but seriously, look at issue #6 for a picture of what KDs constituent lorentzians looked like for a tumour. Unfortunately there was nothing that close to the water peak |
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Could this second peak around water be related to MT? I seem to remember firas sketching out what a MT peak would look like at high power (a central peak swallowed up by a high baseline) |
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hmm good idea. Although, I seem to remember the MT peak being much much wider. Similar to this:
Sheth, V. R., Li, Y., Chen, L. Q., Howison, C. M., Flask, C. A., & Pagel, M. D. (2011). Measuring in vivo tumor pHe with CEST-FISP MRI. Magnetic Resonance in Medicine, 67(3), 760–768. doi:10.1002/mrm.23038 |
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... But maybe the width depends on the pulse power...? |
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Okay, just updating this thread with results from pixel-by-pixel maps of the CEST fits. I've checked the fits for a few pixels, and all the fits look pretty good. Just to be clear, the maps below are generated using the least-squares fitting method where initial parameters are given and both the peak heights, widths, and peak positions are allowed to roam.
The maps below include only pixels around the brain (non white). I'll look at things in more detail tomorrow, to find the reason why some fits are failing.
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thanks firas! it's a good first start! On 2/8/2015 1:40 AM, firasm wrote:
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These are from the MCMC fitting method - they look a bit better, but still hard to see structure. All integral maps are line width x amplitude
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yes - a bit of a mess. A normal brain might not be an ideal playing firasm wrote:
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From Andrew's email:
Tried to fit this with multiple lorentzians
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