Improved Detection of Bone Metastases in Children and Young Adults with Ferumoxytol-enhanced MRI

Purpose: To evaluate if ferumoxytol can improve the detection of bone marrow metastases at diffusion-weighted (DW) MRI in pediatric and young adult patients with cancer. Materials and Methods: In this secondary analysis of a prospective institutional review board-approved study (ClinicalTrials.gov identifier NCT01542879), 26 children and young adults (age range: 2-25 years; 18 males) underwent unenhanced or ferumoxytol-enhanced whole-body DW MRI between 2015 and 2020. Two reviewers determined the presence of bone marrow metastases using a Likert scale. One additional reviewer measured signal-to-noise ratios (SNRs) and tumor-to-bone marrow contrast. Fluorine 18 (F-18) fluorodeoxyglucose (FDG) PET and follow-up chest CT, abdominal and pelvic CT, and standard (non-ferumoxytol enhanced) MRI served as the reference standard. and Wilcoxon signed rank test. Results: The SNR of normal bone marrow was significantly lower at ferumoxytol-enhanced MRI compared with unenhanced MRI at baseline (21.380 +/- 19.878 vs 102.621 +/- 94.346, respectively; P =.03) and after chemotherapy (20.026 +/- 7.664 vs 54.110 +/- 48.022, respectively; P =.006). This led to an increased tumor-to-marrow contrast on ferumoxytol-enhanced MRI scans compared with unenhanced MRI scans at baseline (1397.474 +/- 938.576 vs 665.364 +/- 440.576, respectively; P =.07) and after chemotherapy (1099.205 +/- 864.604 vs 500.758 +/- 439.975, respectively; P =.007). Accordingly, the sensitivity and diagnostic accuracy for detecting bone marrow metastases were 96% (94 of 98) and 99% (293 of 297), respectively, with the use of ferumoxytol-enhanced MRI compared with 83% (106 of 127) and 95% (369 of 390) with the use of unenhanced MRI. Conclusion: Use of ferumoxytol helped improve the detection of bone marrow metastases in children and young adults with cancer. (c) RSNA, 2023

Automated summary

The purpose of this study was to evaluate the effectiveness of ferumoxytol in improving the detection of bone marrow metastases in pediatric and young adult patients with cancer using diffusion-weighted MRI. The results showed that ferumoxytol-enhanced MRI scans had higher sensitivity and diagnostic accuracy in detecting bone marrow metastases compared to unenhanced MRI scans.