Evidence for the Role of Intracellular Water Lifetime as a Tumour Biomarker Obtained by In Vivo Field‐Cycling Relaxometry

It was established through in vivo T(1) measurements at low magnetic fields that tumour cells display proton T(1) values that are markedly longer than those shown by healthy tissue. Moreover, it has been found that the elongation of T(1) parallels the aggressiveness of the investigated tumour. The T(1) lengthening is associated with an enhanced water exchange rate across the transcytolemmal membrane through an overexpression/upregulation of GLUT1 and Na(+)/K(+) ATPase transporters. It follows that the intracellular water lifetime represents a hallmark of tumour cells that can be easily monitored by measuring T(1) at different magnetic field strengths ranging from 0.2 to 200 mT.