Fusion imaging using a hybrid SPECT-CT camera improves port perfusion scintigraphy for control of hepatic arterial infusion of chemotherapy in colorectal cancer patients

Purpose: Exclusive and homogeneous perfusion of the liver is considered essential for the efficacy of hepatic arterial infusion of chemotherapy (HAI). The aim of this study was to evaluate port perfusion scintigraphy in colorectal cancer patients using a hybrid SPECT-CT system for control of minimally invasive intra-arterial port systems within the scope of a phase II trial. Methods: In 24 consecutive patients, the perfusion territories of intra-arterial hepatic port systems were assessed by port scintigraphy with Tc-99m-labelled macroaggregated albumin employing planar imaging, SPECT and SPECT-CT (acquired with a hybrid SPECT-CT camera). The results of blinded reading of the scintigraphic modalities concerning the intra- and extrahepatic perfusion pattern were compared with combined image analysis (angiography and contrast-enhanced dedicated CT) and patient history for validation. Results: Extrahepatic perfusion was correctly seen in three patients, while suspected extrahepatic perfusion could be excluded in one. In 46 liver lobes, perfusion patterns were correctly visualised by SPECT-CT in 100% of cases (planar, 67%; SPECT, 86%). Assessing the perfusion pattern inside the liver on a segmental basis (segments, n=138), SPECT-CT revealed correct segmental assignment of tracer distribution in 100% and was significantly superior to SPECT alone (accuracy, 84%; p < 0.001). The scintigraphic findings resulted in changes in therapeutic management in 8/24 patients (33%); in two of these the relevant findings were visualised only by SPECT-CT. Conclusion: In patients receiving HAI, port perfusion scintigraphy by fusion imaging with a hybrid SPECT-CT system provides important information for therapy optimisation and appears to be superior to SPECT alone.