T-1-WEIGHTED DYNAMIC MRI WITH NEW SUPERPA RAMAGNETIC IRON-OXIDE PARTICLES (RESOVIST(R)) - RESULTS OF AN IN-VITRO AND IN-VIVO STUDY WITH 25 PATIENTS

Purpose: Evaluation of the diagnostic usefulness of the T-1-effect of Resovist(R) (SPIO) for dynamic MRI of the liver. Method: In-vitro meas urements of a dilution series with T-1-weighted FIASH and SE sequences and investigation of 25 patients with known focal liver lesions with a T-2-weighted TSE sequence and a dynamic T-1-FLASH sequence. Results: T-1-weighted MRI with Resovist(R) in vitro showed a positive enhancem ent at low concentrations and a negative enhancement at higher concent rations. In-vivo T-1-weighted dynamic MRI liver parenchyma demonstrate d a positive enhancement 30 s post contrast, followed by a continuous slope of signal intensity and a negative enhancement (greater than or equal to 60 s). Spleen, portal venous vessels and haemangiomas showed an early increase in signal intensity followed by a decreasing positiv e enhancement, but without negative enhancement. During the perfusion phase metastases showed a small but not significant increase in signal intensity. In 80% a positive ring enhancement could be observed aroun d metastases. Conclusion: Resovist(R) exhibits a diagnostically useful T-1-effect. An evaluation of the perfusion of focal liver lesions dur ing the distribution phase is possible with dynamic T-1-weighted MRI. This approach may further improve characterisation of focal liver lesi ons.