Variable patterns of technetium-99m MAA perfusion in the therapeutically embolized liver

Hepatic perfusion studies using 99mTc macroaggregate albumin (MAA) particles have been utilized to document arterial catheter position and flow distribution in patients who are to undergo hepatic arterial chemotherapy infusion (HAI). We have recently been treating nonresectable hepatic neoplasms with transcatheter hepatic arterial chemoembolization (HAE) followed by HAI. The MAA perfusion studies in these patients show variable patterns. For this reason, we have reviewed our recent experience with 15 patients who underwent 21 HAEs and HAIs. The arteriograms and the MAA perfusion studies were reviewed and correlated. Early (within 4 hr of embolization) perfusion studies revealed flow reversal, or MAA reflux into an undesirable location in 11 cases. Two selected follow-up scans in 24 hr revealed restoration of flow to the embolized lobe, confirming the proper position of the catheter for HAI. Knowledge of both the hepatic arterial anatomy, and of the specific embolization procedure will allow accurate interpretation of the MAA perfusion study. Initial flow reversal, or MAA reflux, should not be interpretated as a malpositioned catheter, but prompt reevaluation after a period of 24 hr to document restoration of antegrade flow is suggested.