[Bone (marrow) edema in magnetic resonance imaging - finding or only signal? A brief look behind the mirror].

An ill-defined area of increased signal intensity in bone marrow seen on water-sensitive magnetic resonance (MR) sequences (e. g. T2, short TI inversion recovery STIR) is usually referred to as "bone marrow edema". It may be observed with traumatic (e.g. bone bruise), inflammatory, osteoarthritic as well as neoplastic processes. Therefore, it can be confusing if the term "bone marrow edema" is used to describe a clinicoradiologic condition or diagnosis. Addressing these imaging findings as "edema equivalent" or "edema-like increased signal intensity" helps to restrict this phenomenon to a magnetic resonance sign and to avoid using it as a radiologic diagnosis. To illustrate this three case examples with corresponding MR images are presented to point out the intention of this article.