Abstract: A contrast imaging method e.g. of the T2* weighted “BOLD” type is adapted by use together with an oxygen challenge to provide imaging for the assessment of the metabolic responses of tissue over a period of time the method utilizing three components, oxygen, deoxyhaemoglobin, and oxyhaemoglobin together with time, to provide four variable parameters which allows oxygen to be used as a metabolic marker that can be utilized in an imaging evaluation of soft tissue and organs, e.g. in the study of viable tissue and organ function or dysfunction, which allows utility in diagnosis and assessment of conditions such as cancer, dementia, circulatory disorders, and autoimmune disorders.