The Abnormal Bone Marrow: MRI Patterns

Abstract

The signal intensity of bone marrow on MR images depends on the balance among fat, water, and bony trabeculae. Normal patterns of red to yellow marrow conversion in relation to age and gender and variations in these patterns depending on daily habits (e.g., smoking, long-distance running), chronic illnesses (e.g., severe anemia), and body habitus (obesity), via the process of reconversion, have already been discussed in Chap. 1. In this chapter, the MRI patterns of the abnormal bone marrow will be analyzed. When dealing with MR images of bone marrow disorders, pattern recognition is an essential step of the diagnostic process. Analysis of the MR pattern of involvement permits a classification of marrow disorders which is based on imaging findings rather than on clinical or laboratory information; it narrows down the differential diagnosis and aids distinction of a “leave alone” finding from one that needs follow-up or further work-up. Pattern assignment may also have important clinical implications regarding prognosis in certain conditions, such as multiple myeloma, as will be discussed in the relevant chapters [1].