Comparison of Ultrasmall Particles of Iron Oxide (USPIO)-Enhanced T2-Weighted, Conventional T2-Weighted, and Gadolinium-Enhanced T1-Weighted MR Images in Rats with Experimental Autoimmune Encephalomyelitis
Vincent Dousset,a,
Lucrecia Ballarinoa,
Christophe Delalandea,
Monique Coussemacqa,
Paul Canionia,
Klaus G. Petrya and
Jean-Marie Cailléa
a From the Laboratoire de NeuroBiologie et NeuroImagerie Expérimentales (V.D., L.B., M.C., J-M.C.), the Laboratoire de Résonance Magnétique des Systêmes Biologiques (C.D., P.C.), and the Laboratoire de NeuroBiologie Intégrative (K.G.P.), Université Victor Segalen Bordeaux2, France.
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FIG 1. Coronal SE T2-weighted (2030/60/4) MR image obtained at 4.7 T in a rat with EAE. The section is at the level of the midbrain (arrowhead indicates the right cerebral hemisphere). A small area of increased signal intensity is present around the sylvian aqueduct (arrow)
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FIG 2. A and B, Coronal SE T2-weighted images of the brains of two rats with clinical EAE, imaged 24 hours after administration of USPIO (AMI-227) at 4.7 T. The section is at the level of the posterior fossa (arrowheads indicate the right cerebellar hemisphere; long arrows, the pons). Numerous lesions are seen as low signal intensities related to the magnetic susceptibility effects caused by iron particles within phagocytic cells (small arrows in A).
FIG 3. Coronal turbo SE T2-weighted (5000/20/1) MR image of the brain of a rat with EAE, imaged 24 hours after administration of AMI-227 at 1.5 T. Multiple areas of low signal are seen within the posterior fossa (arrows).
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FIG 4. Histologic sections at a site of low signal on MR images after administration of AMI-227.
A, Hematoxylin-eosin stain shows multiple perivascular inflammatory infiltrates (arrows).
B, Prussian blue stain for iron (Perls' technique) shows staining of perivascular cells (arrows).
>>FIG 5. Histologic section at the level of the posterior fossa (arrow indicates fourth ventricle) shows immunostaining with an ED1 antibody macrophage marker. Macrophage infiltrates correspond to magnetic susceptibility–related low signal intensities on T2-weighted images 24 hours after USPIO injection and to infiltrating cells on hematoxylin-eosin stain.
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