Splenic imaging with ultrasmall superparamagnetic iron oxide ferumoxtran-10 (AMI-7227): Preliminary observations

Purpose: Ferumoxtran-10 (ultrasmall superparamagnetic iron oxide: Combidex. AMI-7227) is a long-circulating MR contrast agent with reticuloendothelial uptake known to enhance tissue TI and T2 relaxation rates. The purpose of this study was to assess the effect of ferumoxtran-10-enhanced MRI in evalu ating focal splenic lesions. Method: Eighteen patients underwent MR evaluation of the spleen. Two of the se patients with exophytic normal splenic tissue (splenules) and 13 of thes e patients with 24 focal splenic lesions (7 cysts. 2 hemangiomas, 7 metasta ses, I infarct, 7 lymphoma) were assessed by T1-weighted gradient echo and T2-weighted fast SE MRI following intravenous administration of ferumoxtran -10 (1.1 mg of Fe/kg). Qualitative analysis involving improved lesion detec tion and/or characterization. additional information from postcontrast imag es affecting staging, and patient management was performed. Quantitative me asurements of lesion-to-spleen contrast-to-noise ratio were also performed. Results: Additional information was provided by ferumoxtran-10-enhanced ima ges in 15 of 18 patients. In 8 of 15 (53%) patients, improved lesion detect ion (i.e,, number of lesions) was obtained on contrast-enhanced images. Imp roved lesion visualization (i.e.. conspicuity) was noted in I I of 15 (73%) of patients. In 10 of 15 (67%) patients, postcontrast imaging provided add itional information leading to lesion characterization. Staging of disease and patient management were affected in 5 of 15 (33%) and 6 of 15 (40%) pat ients. respectively. Conclusion: Ferumoxtran-10 is a promising contrast agent for the evaluation of focal splenic lesions.