MR-imaging and Prussian blue histology visualizes SPION content in knee joints of mice.

<p>Coronal MR images of knee joints <i>ex vivo</i>. T1-weighted gradient echo sequence, 3D isotropic resolution of 310μm, TR/TE 14.3/5.9ms and flip angle 12°. Blue arrows indicate hypointense signal in the region of SPION uptake in synovial tissue. (A) Control knee joint with AIA and no SPION. (B) Control knee joint without AIA and with i.v. injected SPION; signal from SPION detected in bone marrow, but not in synovium. (C) AIA knee joint i.v. injected with SPION; signal from SPION detected in bone marrow and synovial tissue. (D) AIA knee joint injected i.a. with SPION; signal from SPION detected in synovial tissue. (E) Prussian blue staining of histological slide of AIA knee joint with SPION injected i.a. Blue arrow indicates Prussian blue staining of SPION taken up by cells of the synovium. Magnification 100x.