CONTEXT: MR imaging enhanced with ultrasmall superparamagnetic iron oxide (USPIO) particles can noninvasively monitor the behavior of novel anti-angiogenesis drugs, according to researchers at the University of Munster in Germany. The group is investigating USPIO-enhanced MR measurements of vascular volume fraction as a surrogate marker for tumor angiogenesis. Results, compiled by Dr. Thorsten Persigehl and colleagues at the university's Institute for Clinical Radiology, were summarized in a scientific poster at the European Congress of Radiology in March.
RESULTS: Tumor-bearing mice were treated intravenously with either an agent inducing thrombosis in selective tumor vasculature (11 mice) or saline (13 mice). All animals underwent MR imaging at 1.5T with a long-circulating USPIO (SHU 555C, Schering) four to eight hours after treatment. USPIO-induced changes to relaxation ( delta R2*) to determine the vascular volume fraction were measured using a T2-weighted dual echo-planar MR sequence.
Parametric delta R2* maps revealed a noticeable reduction in tumor perfusion in the treatment group compared with controls. This change was observed as early as four hours after injection with the anti-angiogenesis agent. Histological analysis confirmed the MR findings, showing extensive tumor thrombosis in the treatment group.
IMPLICATIONS: The study confirmed that USPIO-enhanced MR imaging measures early tumor response to anti-angiogenesis treatment, according to Persigehl. Radiologists will readily adopt this class of MR contrast media when it is introduced for clinical use, he said.
Stay at the forefront of radiology with the Diagnostic Imaging newsletter, delivering the latest news, clinical insights, and imaging advancements for today’s radiologists.
FDA Expands Approval of MRI-Guided Ultrasound Treatment for Patients with Parkinson’s Disease
July 9th 2025For patients with advanced Parkinson’s disease, the expanded FDA approval of the Exablate Neuro platform allows for the use of MRI-guided focused ultrasound in performing staged bilateral pallidothalamic tractotomy.