Figure 1
From: Functional imaging: what evidence is there for its utility in clinical trials of targeted therapies?
Schematic showing the currently most used functional techniques in the clinic and illustrating their mechanism of action. The output measures from each of these are shown in pink. Dynamic contrast enhanced MRI with output measured as rate constants (Ktrans and Kep) of gadolinium transfer between intravascular and extravascular compartments measured in ml min–1. Diffusion weighted MRI with measured apparent diffusion coefficient (ADC) measured in mm2 s–1. Intrinsic susceptibility weighted MRI with output the relaxation rate constant R2* measured in s−1. Dynamic contrast enhanced CT, with output of relative blood flow (rBF) and relative blood volume (rBV) measured in ml min–1 and ml ,respectively. Parameters in PET are measured as maximum standardised uptake values (SUVmax) of the radioligand. In US, quantified parameters are change in US backscatter before and after injection of microbubbles and represented as integrated area under the curve (IAUC) and rBF.
