Pilot Study Evaluating Use of Lymphotrophic Nanoparticle-Enhanced Magnetic Resonance Imaging for Assessing Lymph Nodes in Renal Cell Cancer

Abstract

To assess lymphotrophic nanoparticle-enhanced magnetic resonance imaging (LNMRI) in identifying malignant nodal involvement in patients with renal neoplasms. MRI was performed in 9 patients with renal masses. All patients were imaged on a GE 1.5T system with phased array body coil. Protocols included T2 and T2* weighted imaging before and after administration of ferumoxtran-10 (Combidex) for the evaluation of lymph node (LN) involvement. All 9 patients underwent nephrectomy. Lymph node dissection (LND) was performed in patients with stage 2 renal cell cancer (RCC), or transitional cell cancer (TCC), per routine clinical practice. Data analysis was performed by 2 radiologists, who were blinded to pathologic results. Nodes that lacked contrast uptake were deemed malignant, and those with homogeneous uptake were deemed benign. Quantitative, retrospective analysis was performed on primary tumors by quantifying T2* with a monoexponential fitting algorithm (Osirix). T2* was quantified before, immediately after, and 24 hours after the administration of ferumoxtran-10. MRI demonstrated 26 lymph nodes within the 9 patients imaged (24 benign and 2 malignant). Pathologic results allowed comparison in 22 of the 26 lymph nodes and demonstrated high sensitivity (100%) and specificity (95.7%). LNMRI demonstrated high sensitivity (100%) and specificity (95.7%) in patients with renal neoplasms. Although in a relatively small sample size, the results are encouraging and warrant a larger, prospective trial.