Diagnosis of plasmocytomas using magnetic resonance imaging

Background. In multiple myeloma 5 different infiltration patterns can be di fferentiated: 1. normal appearance of bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltrati on, 5."salt- and pepper" pattern with inhomogeneous bone marrow with interp osition of fat islands. Methods. For the fast and total acquisition of all patterns a combination o f a T1-weighted spin echo sequence and a fat suppression technique is super ior. The focal involvement is clearly demonstrated as areas of high signal intensity on e.g. STIR images. Diffuse involvement can be quantified object ively by calculation of the percentage of signal intensity increase after c ontrast material injection. MRI is superior to X-ray in focal and diffuse i nvolvement. With ultrafast sequences a "screening" of the whole red bone ma rrow as for myeloma infiltration is possible. Prognosis. In prognosis studies diffuse infiltration is inferior to focal i nvolvement. Patients without bone marrow infiltration have a significantly longer survival than patients with bone marrow infiltration in MRI at the t ime of diagnosis. However, even patients in stage one of disease (Durie and Salmon) a nd negative X-ray films can show bone marrow infiltration in MRI . Those patients often show an early disease progression. Good response to therapy in focal involvement are: reduction of signal intensity on T2- weig hted spin echo images, lack or rim-like enhancement after contrast material injection or even a normalisation of bone marrow signal. In case of diffus e involvement a partly patchy reconversion to fatty marrow can be seen.