We have investigated the acute and sustained hemodynamic effects of
octreotide on hepatic
metastases of midgut
carcinoids using contrast-enhanced dynamic magnetic resonance imaging (MRI). Seven patients with the
carcinoid syndrome and metastasized midgut
carcinoid tumors underwent functional dynamic multi-phase
gadolinium-enhanced MRI of selected liver
metastases at baseline and 60 min after the subcutaneous (s.c.) administration of 100 microg
octreotide, and also after 3 months with three times daily (t.i.d.) 100 microg
octreotide s.c. Baseline MRIs showed the typical aspect of
carcinoid liver
metastases with a very bright signal on the T2-weighted sequences and intense enhancement in the arterial phase after injection of
gadolinium-diethylenetriaminepentaacetate. MRIs 60 min after the s.c. administration of 100 microg
octreotide showed a 34.9 +/- 6.2% (mean +/- SD) reduction in relative enhancement in the selected liver
metastases as compared to baseline. In 2 patients, however, there was no (significant) reduction in the relative enhancement in the selected liver
metastases 60 min after the s.c. administration of 100 microg
octreotide as compared to baseline. Only in 2 patients did the MRIs at 3 months show a decrease in relative enhancement in one of the selected liver
metastases. At 3 months, with 100 microg
octreotide s.c. t.i.d., there was no correlation between the change in relative enhancement on MRI and the change in 24-hour
5-HIAA excretion. There is thus only an acute effect of
octreotide on the perfusion of liver
metastases. This study further shows that contrast-enhanced dynamic MRI can be a very useful tool for studying hemodynamic effects of medical
therapies on liver
metastases in patients with metastatic midgut
carcinoids.