Localized in vivo ¹H spectroscopy and chemical shift imaging of the bone marrow in leukemic patients

Abstract

Six healthy volunteers, ten patients with acute leukemia, one patient with hypersplenia and two with bone marrow carcinoris were studied. Nine patients with leukemia were restudied during chemotheraphy. A double spin echo localization method, implemented on a 1.5 T whole body unit was used for ¹H magnetic resonance spectroscopy (MRS). A cubic (13 mm)³ voxel was chosen in a midlumbar vertebra. For chemical shift imaging (CSI) the SENEX sequence was used. We recorded fat and water images in a representative midsagittal plane. Patients with acute leukemia and hypercellular bone marrow a severe reduction or loss bone marrow fat signal and an increased water signal. Water T1 increaed during therapy in three patients. The bone marrow fat reappeared in the spectra and chemical shift images within 2 or 3 weeks in responders and remained unchanged or reappeared later in non-responders. A normal fat signal could be detected in leukemic patients without hypercellular bone marrow. Specificity was missing for ¹H MRS and CSI; marrow carcinosis and benign stimulation (hypersplenia) could not be seperated from leukemia. In clinical routine, CSI may have advantages over ¹H MRS, because a large anatomic field can be examined. Inhomogenous fat signal distrbutions can be detected and were seen in sveral cases during therapy. ¹H MRS and CSI allow non-invasive therapy monitoring of leukemic patients adn might be of prognostic value.