Magnetic resonance imaging and regional biochemical analysis of experimental brain tumours in cats.

Multiexponential evaluation of in vivo multi-echo T2 measurements at 4.7T in cat brain with implanted tumour led to monoexponential results in all tissues. T2 of normal brain tissue, tumour and oedema was 67 ms, 10-100 ms and 90-180 ms, respectively. In the ventricles biexponential solutions were observed with T2 values and relative contributions of these two components differing for ipsi- and contralateral side. Best discrimination between tumour and oedema was achieved by the magnetization value M (O), and between oedema and normal brain tissue by T2. T2 values were compared with in vitro biochemical analyses for ATP, lactate, glucose, tissue electrolytes and water content. NMR parameters provide reliable predictions about the water content and metabolic state of oedema, but not of the tumour.