The purpose of our study was to assess the effects of intravenous administration of ferumoxides on normal and abnormal vertebral bone marrow T1 and T2 relaxation times. Changes in bulk T1 and T2 relaxation times induced by intravenous administration of ferumoxides were determined in the normal vertebral marrow of two healthy subjects and four patients. In the four patients, changes in bulk T1 and T2 values induced by furomoxides injection were also determined in 12 vertebral metastases. Relative to precontrast relaxation time values, bulk T1 and T2 values of normal bone marrow had declined by a mean of 24% and 19%, respectively, in the two subjects and the four patients 45 minutes after ferumoxides administration. Relative to precontrast values, bulk T1 and T2 values of abnormal bone marrow had decreased by a mean of 16% and 2%, respectively. Decreases in bulk T1 and T2 values in normal bone marrow and in bulk T1 values in metastases were statistically significant (P<0.001). Changes in bulk T2 values observed in metastases were not statistically significant. Quantitative MRI demonstrates that ferumoxides infusion induces a decrease in bulk T1 and T2 relaxation times of normal bone marrow. It also suggests a lack of T2 shortening in bone metastases.