Bone marrow disorders

Abstract

Bone marrow imaging is part of various muskuloskeletal diagnosic tasks including detection and staging of diseases originating in the bone marrow like multiple myeloma, lymphoma, leukaemia and myeloproliferative disorders, imaging of secondary bone marrow involvement (metastasis) in malignant diseases and reactive bone marrow changes due to stress or trauma of bones and joints. Nonneoplastic reasons for changes of bone marrow cellularity are marrow reconversion, which can be caused by various diseases including haemolytic anemias, chronic infection, smoking, and menstruation. These reactive changes must be differentiated from diffuse malignant bone marrow infiltration. By far the most common signal change of bone marrow is related to pathologic load to bone and joints. Of all the imaging methods used to image bone marrow, such as projection radiography, computed tomography (CT), magnetic resonance (MR) imaging, bone scintigraphy, and positron emission tomography (PET), only MR imaging is capable of direct visualizing bone marrow cells, the remaining methods use indirect ways to image bone marrow pathologies. The basic principle of bone marrow imaging in MRI consists of determining cellularity and the amount of intracellular and extracellular water in the bone marrow cavity. Both, celluarity and interposition of water is visualized in demonstration of differencies in the fat-water ratio, as hematopoetic and malignant cells consist mainly of water whereas fat cells contain mainly fat. © 2005 Springer-Verlag Italia.