Description:
Summary
Tracking immune responses in chemotherapy treated glioblastomas is important for interpreting disease progression, but current methods are invasive and require biopsies. OHSU researchers have developed an MRI-based method to detect tumor-associated macrophages to enable non-invasive monitoring of glioblastomas for research and surgical planning.
Technology Overview
Tumor-associated macrophages (TAMs) are a major constituent of the immune response to glioblastoma therapy, but assessing changes in this microenvironment is difficult and often requires invasive biopsies. OHSU researchers have developed a non-invasive imaging metric to assess inflammatory changes, which could improve glioblastoma clinical outcomes. This technique capitalizes on the observation that iron (Fe)-based MRI contrast agents, such as ferumoxytol, accumulate in the extravascular compartment and are preferentially taken up by TAMs. The combined imaging and analytic approach developed at OHSU allows for specific localization of extravascular Fe-contrast at the delayed phase imaging time point within glioblastomas. Importantly, this method corrects for persistent residual intravascular Fe-contrast agent accumulation, which can lead to false positive inflammatory “hotspot” detection. In a cohort of 23 patients with glioblastoma, this methodology successfully separated and localized both the intravascular and extravascular signal components of ferumoxytol. This extravascular contrast signal provides for the first time a biomarker of innate immune cell accumulation within tissues and may be more specific metric of TAMs than current use of uncorrected T1- or susceptibility-weighted techniques. Ultimately this method could be used to quantify and monitor innate immune cell infiltration within many different tissues and could have applications in disease processes beyond glioblastoma.
Publication
Barajas RF Jr, et al., Distinguishing Extravascular from Intravascular Ferumoxytol Pools within the Brain: Proof of Concept in Patients with Treated Glioblastoma. AJNR Am J Neuroradiol. 2020 Jul;41(7):1193-1200. Link
Licensing Opportunity
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