EVALUATION OF HYDROXYETHYL-STARCH-FERRIOXAMINE AS AN INTRAVASCULAR MRCONTRAST AGENT FOR ASSESSMENT OF MYOCARDIAL PERFUSION

Purpose: The present study was carried out to evaluate a new intravasc ular contrast agent hydroxyethyl-starch-ferrioxamine (HES-FO) for asse ssment of myocardial perfusion. Material and Methods: Isolated pig hea rts were perfused with a crystalloid cardioplegic solution in a Langen dorff apparatus. MR images were acquired along the short cardiac axis using T1- and T2-weighted methods. Gd-DTPA and HES-FO were used as th e standard extracellular and test contrast agents, respectively.Result s: We found that T1-weighted signal intensity was not significantly af fected by HES-FO, but increased significantly in presence of Gd-DTPA. On the other hand, HES-FO resulted in a rapid, transient but significa nt decrease in T2-weighted signal intensity. Although Gd-DTPA also de creased T2-weighted signal intensity considerably, it took much longe r for the T2-weighted signal intensity to return to its initial stead y-state with Gd-DTPA than with HES-FO. Moreover, increasing the dose o f HES-FO (from 0.0023-0.0138 mmol/kg b.w.) had no effect on the time a t which the T2 effect reached its maximum or on the duration of the T 2 effect. However, these times and durations were affected significan tly by increasing the dose of Gd-DTPA (0.0023-0.027 mmol/kg b.w.). Con clusion: The results suggest that HES-FO provides information regardin g myocardial vascular flow which cannot be obtained using Gd-DTPA. It is expected that the combined use of intravascular and extracellular t ype contrast agents will allow more complete assessment of tissue perf usion.