Radiology is the most visually oriented of all medical specialties. Because the patient is reduced to a set of images viewed remotely, cues provided by sound, touch and even smell are denied to the radiologist. Thus learning is gained not just from observations directly but also from radiologic signs, many of which are metaphoric. Is knowledge engendered or merely decorated by reference to figurative connections? This essay provides data and some answers to the enduring speculation on the power of metaphor and its pertinence to diagnostic imaging.

How do we learn things in Radiology? Our specialty is now recognized as probably the most dynamic in all of medicine. Characterized by the implementation of both new instruments and new observations, it has revolutionized diagnosis. But we must understand some limitations. We deal only in images. Images are not reality. Reality is the patient or organs in the patient, or the supporting structures attached to those organs, or the cells in both parenchyma and supporting tissue, or the flow of substances and impulses throughout the body. Aside from interventional radiology we gain knowledge only through visual depiction of those structures and phenomena. In essence, we are narrowly informed, having at our disposal only a fraction of the sense data that could be acquired, interpreted and assimilated in order to gain and retain knowledge.

Other specialists interact more fully with the actual human being they assess. They speak with them as they look at them. They see their gestures and predominately they learn from speech what the patient is complaining about. Aural cues also include the sounds they have been able to discern from auscultation of the chest, heart, and abdomen. All other physicians directly involved with diagnosis also touch patients. Physical examination with its tactile observations allows inferences to be drawn about the presence and particularities of disease. In some instances, olfactory clues also have relevance about mental and physical conditions that are specifically associated with distinctive smells.

But for radiologists, we just have pictures to go by. Incisive images for sure but they are merely simulacra, to use a fancy word, not the thing in itself. Unlike other physicians we cannot, at one encounter, look directly, or hear or touch. Having each type of sensual information can reinforce, question or refute our professional opinions. We are remote. We can only see and reflect, usually at a distance in space and often after an interval of time.