Compositional changes in vertebral bone marrow during treatment for acute leukemia: assessment with quantitative chemical shift imaging

A modified Dixon chemical shift imaging technique was used to quantify longitudinal changes in bone marrow that occur during induction chemotherapy in patients with acute leukemia. Results were correlated with those of bone marrow biopsy. Forty-seven quantitative images were obtained with a 0.6-T whole body imager in a total of 11 patients over the course of treatment. Quantitative measures of fat fractions and water and fat component T1 and T2 relaxation times were determined, as well as average relaxation times. Imaging results showed sequential increases in fat fractions among responding patients (n = 9), consistent with biopsy-confirmed clinical remission. In the two patients who later relapsed, sharp decreases in fat fractions were noted. In the two patients who failed to regenerate normal marrow, unchanging, low fat fractions were seen. Water component T1 values reflected posttherapeutic changes in the hematopoietic elements. Quantitative chemical shift imaging proved useful in assessing treatment response in acute leukemia during early bone marrow regeneration and, later, in ascertaining remission or relapse.