Iron oxide particle-enhanced MRI suggests variability of brain inflammation at early stages after ischemic stroke.
OBJECTIVE
Inflammation contributes to brain damage caused by ischemic stroke. Ultrasmall superparamagnetic iron oxide (USPIO)-enhanced MRI allows noninvasive monitoring of macrophage recruitment into ischemic brain lesions. In this study, we determined the extent of USPIO enhancement during early stages of ischemic stroke.


METHODS
Twelve consecutive patients with typical clinical signs of stroke underwent multimodal stroke imaging at 1.5-T within 24 hours of symptom onset. They received intravenous USPIO (ferumoxtran) infusion at 26 to 96 hours (mean, 44 hours) after stroke. A total of four follow-up MRI scans were performed 24 to 36 hours, 48 to 72 hours, 7 to 8 days, and 10 to 11 days after USPIO infusion.


RESULTS
Nine patients were included in the final analysis. Parenchymal USPIO enhancement occurred in 3 of 9 analyzed patients and was mainly evident on T1-weighted spin-echo images. USPIO-dependent signal changes were spatially heterogeneous, reflecting the distinct patterns of hematogenous macrophage infiltration in different lesion types.


CONCLUSIONS
Our findings suggest a variable extent and distribution of macrophage infiltration into early ischemic stroke lesions. USPIO-enhanced MRI may help to more specifically target antiinflammatory therapy in patients with stroke.
Saleh
Andreas
A
Institute of Diagnostic Radiology, Heinrich-Heine-University, Moorenstr. 5, D-40225 Düsseldorf, Germany.
Schroeter
Michael
M
Ringelstein
Adrian
A
Hartung
Hans-Peter
HP
Siebler
Mario
M
Mödder
Ulrich
U
Jander
Sebastian
S
D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000276:immunology / Q000473:pathology*; D003287:Contrast Media; D003911:Dextrans; D042241:Early Diagnosis; D004660:Encephalitis / Q000276:immunology / Q000473:pathology*; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron; D008264:Macrophages / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides; D020521:Stroke / Q000276:immunology / Q000473:pathology*
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide