Role of scintigraphy in establishing optimal perfusion in hepatic arterial infusion pump chemotherapy

Optimal injection protocol for CT evaluation during hepatic arterial infusion chemotherapy

OBJECTIVE

As an imaging modality for follow-up during continuous or repeated hepatic arterial infusion chemotherapy using a hepatic intra-arterial indwelling catheter, the usefulness of CT while infusing contrast through the indwelling catheter (reservoir port) was examined.

METHODS

Using reservoir ports implanted in eight patients with hepatic metastasis from colon cancer, radioisotope perfusion scintigraphy (RI), CT (three rates of infusion of contrast were used), and digital subtraction angiography (AG) were performed to compare the modalities' ability to visualize the intrahepatic and abnormal extrahepatic distributions.

RESULTS

CT (infusion rate 0.1 mL/sec) was superior to AG and RI in terms of the ability to visualize intrahepatic distribution, particularly in small areas, and facilitated 3D delineation of the distribution. In evaluating extrahepatic distribution, CT also outperformed the other modalities.

CONCLUSIONS

For imaging study follow-up during hepatic arterial infusion chemotherapy, CT proved to be more useful than conventional RI and AG.

Perfusion of colorectal liver metastases and uptake of fluorouracil assessed by H2(15)O and [18F]uracil positron emission tomography (PET)

Perfusion and fluorouracil (FU) accumulation were assessed using positron emission tomography (PET) with H2(15)O and 18FU in 36 patients with colorectal liver metastases. The tracers were injected intravenously and via the hepatic artery. Standard uptake values (SUV) were calculated using a region of interest (ROI) technique. The perfusion of non-tumorous liver tissue was similar after intravenous (i.v.) and intra-arterial (i.a.) assessment [mean of 2.67 (s = 0.61) and 2.2 (s = 0.45)]. Metastases were found to be hypoperfused compared to normal liver tissue after i.v. examinations [mean 1.73 (s = 0.77)]; i.a. injections revealed greater perfusion in metastases [mean 6.41 (s = 5.47)]. Single metastases showed up to 10 times greater perfusion with the i.a. injection route than with the i.v. one. However, lesions with no change or lower perfusion were also observed. Generally, accumulation of 18FU in metastases after i.v. infusion was less than after i.a.. Correlation of i.v. perfusion and uptake was moderate (r = 0.54, P = 0.0001); i.a. correlation was only slightly better (r = 0.61, P = 0.008). Perfusion as measured by H2(15)O-PET does not generally predict uptake of 18FU in colorectal liver metastases. To measure FU uptake using PET and 18F seems to be the most accurate method. It would allow one to identify individual patients with considerably greater accumulation of 18FU following i.a. administration who should profit from a cross-over to intrahepatic chemotherapy.