MR Characterization of the hemapoetic bone marrow. Findings in generalizedneoplasia and treatment monitoring

Purpose. Methodological work was performed in the field of magnetic resonan ce imaging (MRI) and spectroscopy (MRS) in order to develop suitable tools for non-invasive characterization of hematopoetic bone marrow. The methods were applied for the assessment of normal Values in healthy persons and to examine patients with generalized hematological diseases or to monitor effe cts of therapies influencing the composition of bone marrow. Methods. Besides standard techniques of MRI as T-1- or T-2-weighted methods , chemical shift techniques for selective visualization of water or lipid c omponents were applied. The method of magnetization transfer (MT) contrast was used with the intention to differentiate between multiple water contain ing tissue compartments (intra-vs, extracellular space). A further approach was the determination of the magnetic field distribution within spongy bon e marrow. Besides investigations in healthy volunteers, prospective clinica l studies were carried out in patients suffering from acute leukemia during their initial treatment and in patients who underwent high dose therapy wi th following peripheral blood stem cell transplantation (PBSCT). Results. Especially MR techniques for selective imaging of water or fat sig nals and proton spectroscopy yielded a high sensitivity to primarily pathol ogical or therapeutically induced changes of hematopoetic bone marrow. Appl ication of MT allowed an improved differentiation of the tissue compartment s under PBSCT, which might result in temporary edema. Storage of hemosideri n in bone marrow after blood transfusions and simultaneous hematopoetic ins ufficiency could be revealed by methods sensitive to magnetic field inhomog eneities. Conclusions. Methods of MRI and MRS allow to non-invasively characterize he matopoetic bone marrow in the course of hematological diseases and during t herapy. Marked changes in the composition of hematological bone marrow are detectable for extensive marrow areas. The prognostic relevance of the find ings has to be evaluated in future follow-up studies.