AVP and neoplasm: Toxicity studies in 4T1 cells indicatedADH’s (37) safety and suitability as a CEST agent.With its small molecular weight and good water solubility, ADH (37) emerged as a promising contrast agent for perfusion imaging.In vivo testing of ADH (37) in a mouse model of breastcancer demonstrated an increase in CEST MRI contrast in tumor tissue.Furthermore, they showed that ADH (37) can be conjugatedto a hydrophilic aldehyde which has polyethylene glycol (PEG) chainsto form an acyl hydrazone with enhanced water solubility and biocompatibility(30).