Title: Enhancement of Hemodynamic Contrast in the Cancerous Breast by Carbogen Inspiration

Hallmarks of the tumor phenotype include increased stiffness [1], enhanced angiogenesis with sluggish perfusion [2], increased vascular leakiness leading to increased interstitial pressures [3], and increased metabolic demand [2]. Separately, it is known that the vascular autoregulation mechanism normally achieves a tight coupling between the vascular supply and prevailing metabolic demand, but that the fidelity of vascular autoregulation may be attenuated in tumor tissue as a consequence of alterations in the vascular endothelium and surrounding vascular smooth muscle [2]. One consequence of this is that many tumor types operate on the brink of hypoxemia, suggesting that the otherwise enhanced supply actually is limited, perhaps as a consequence of disturbances in hydrostatic pressures caused by vascular leakiness and changes to the interstitium scaffolding [1].