ALB and neoplasm: Tumour vessel permeability has been investigated on xenograft models of metastatic and non-metastatic breast and prostate tumour using MRI albumin-GdDTPA contrast agent, providing evidence that an adequate vascularisation and/or permeability is needed for metastasis to occur.12 Overall, these studies highlight the importance of MRI-based methods that can provide sufficient spatial resolution, depth penetration and pH accuracy for non-invasively assessing tumour pHe and for accurate quantification of its heterogeneity.