Target Volume Determination 2015

T2*w Perfusion MRT

Transient signal loss by intravascular CM

Perfusion MRI = Dynamic contrast susceptibility imaging

170,0000

137,5000

Diffusion

105,0000

Signal (a.u.) 72,5000

40,0000

t (s) 0,0000 26,2500 52,5000 78,7500 105,0000

T2*-weighted MRI

Diffusion MRI: How it works • First gradient field induces dephasing » Signal loss • Inverted gradient field induces rephasing » Restoration of signal • Effect: – Stationary protons: » Return into phase and regain signal – Moving protons » Incomplete restoration of signal » Persistant signal loss

First Gradient: Dephasing

Second gradient: Rephasing Stationary protons