[MRI of arthritis with the USPIO SH U 555 C: optimization of T1 enhancement]
Dokumenttyp:
Evaluation Studies; Journal Article
Autor(en):
Simon, G; Daldrup-Link, H; von Vopelius-Feldt, J; Wendland, M; Fu, Y; Schlegel, J; Rummeny, E
Abstract:
PURPOSE: To optimize contrast agent dose and pulse sequence parameters in order to achieve a maximal T1 enhancement in arthritic knee joints with ultra small superparamagnetic iron oxides (USPIO)-enhanced MRI. MATERIALS AND METHODS: Antigen-mediated arthritis was induced in the right knee of nine Sprague Dawley rats. The arthritic knee joint as well as the contralateral normal knee were investigated in a 2 Tesla MR scanner before as well as in short intervals up to 2 h after USPIO injection, using T1-weighted gradient echo (GE) sequences. Three rats each received intravenous injections of the new USPIO SHU 555 C (SH U 555 C, Schering AG, Berlin) at doses of 40, 100 and 200 micromol Fe/kg. Pulse sequence parameters of the GE-sequence were optimized by varying flip angles (alpha) and echo times (TE). Changes in signal intensities (SI) of the arthritic knee and contralateral normal knee were quantified as DeltaSI (%) = /([SIpost - SIpre] / SIpre) x 100 %/ and compared with histopathology. RESULTS: Histology of the arthritic knees demonstrated a marked inflammatory proliferation of the synovium. The USPIO SH U 555 C caused a significant increase in signal intensity of the arthritic joints on T1-weighted MR images (p < 0.05). This effect was optimized using a flip angle of 60-70 degrees, a minimal TE and a dose of 200 micromol Fe/kg. Visually the contralateral normal knee did not show any USPIO enhancement. CONCLUSION: Inflammation can be depicted with marked T1 enhancement by the USPIO SH U 555 C using high contrast agent doses and optimized MR pulse sequence parameters.