Text book problem $5\mathrm{.}20.$ A brain tumor has a lower concentration of water than

surrounding healthy tissue. The T$1$ value of the protons in the tumor is shorter

than that of the protons in healthy tissue, but the T$2$ value of the tumor protons is

longer. Which kind of weighting should be introduced into the imaging sequence

in order to ensure that there is contrast between the tumor and healthy tissue. If

a large concentration of superparamagnetic contrast agent is injected and

accumulates in the tumour only, which kind of weighting would now be optimal?

$(25$ pt$.)$