CONTRIBUTION OF SINEREM(R) USED AS BLOOD-POOL CONTRAST AGENT - DETECTION OF CEREBRAL BLOOD-VOLUME CHANGES DURING APNEA IN THE RABBIT

The authors suggest that ultra-small paramagnetic iron oxide (USPIO) p articles used as blood pool contrast agents may increase the sensitivi ty of midfield MRI (i.e., less than 1.5 Tesla) to physiological variat ions in cerebral blood volume, This hypothesis was tested on a rabbit model of apnea which increases pCO(2) and cerebral blood volume, Using Sinerem(R) as the USPIO at a blood concentration of 60 mu mol iron/kg body weight, an 8% T-2-weighted signal decrease could be observed at 1.0 T with 25-33% increase in pCO(2). Comparatively, in the absence o f USPIO, T-2-weighted signal dropped only 4% during apnea and after m ild hyperoxygenation beforehand, due to increased deoxyhemoglobin cont ent, These preliminary data suggest that USPIOs could play an importan t role in functional MRI at midfield strength, by sensitizing the sign al to cerebral blood volume changes.