- #1
schulzy
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Homework Statement
We will make a Spin-Echo experiment, and we know [tex]\rho_{w}, T1_{w},T2_{w}, \rho_{g},T1_{g},T2_{g}[/tex], where T1 and T2 are relaxation time,[tex]\rho[/tex] is a proton density, and g mean gray matter, w mean white matter.
We search TR and TE, TR is a repetition time, TE is an echo time. We need this two time define, and be the different of signal intensity biggest. Signal intensity: [tex]SI=\rho\left(1-e^{-\frac{TR-TE}{T1}}\right)e^{-\frac{TE}{T2}}[/tex]
also we have two equation
[tex]SI_{w}=\rho_{w}\left(1-e^{-\frac{TR-TE}{T1_{w}}}\right)e^{-\frac{TE}{T2_{w}}}[/tex] and
[tex]SI_{g}=\rho_{g}\left(1-e^{-\frac{TR-TE}{T1_{g}}}\right)e^{-\frac{TE}{T2_{g}}}[/tex]
and I don't know, what should I do, I divide or subtract the two equation. And after this operation we make a partial derivation:
[tex]\frac{\partial}{\partial TR}f=0[/tex] and [tex]\frac{\partial}{\partial TE}f=0[/tex]
Is this place a minimum or maximum place?
Also my question is, divide I or subtract the two equation?