Does streaming affect the cerebral distribution of infraophthalmic intracarotid chemotherapy?

BACKGROUND AND PURPOSE: The development of new non-ocular-toxic drugs has enabled infraophthalmic chemotherapeutic infusion. We assessed whether streaming occurs with infraophthalmic, high cervical internal carotid artery (ICA) delivery of chemotherapeutic agents by means of conventional angiographic catheters. METHODS: Six patients with high-grade gliomas treated with monthly carotid intraarterial chemotherapy were studied. Chemotherapy delivery and distribution was modeled by technetium 99m hexylmethyl-propyleneamine oxine (HMPAO), a first-pass agent. Each patient received 0.5 mCi (18.5 MBq) of ^99mTc-HMPAO in 50-mL of saline intraarterially in the ICA at the C1-C2 level. Injections were given twice, at two different injection rates: 0.08 mL/s at one therapeutic session and 6 mL/s a month later. The slow injection rate modeled the slowest rate used in the delivery of chemotherapy into the ICA. The higher rate was selected to avoid any possibility of uneven mixing, by replacing intracarotid blood completely and by using a turbulent injection rate that destroys laminar flow and intraarterial streaming. Single photon emission CT (SPECT) was performed 2 hours after injection. For each patient, the corresponding SPECT sections at the two injection rates were compared. RESULTS:No differences were noted in ^99mTc-HMPAO distribution between the two injection rates in any of the patients. However, some of the rapid injection rate SPECT scans showed extension of the ^99mTc-HMPAO uptake into adjacent watershed territories. CONCLUSION: There was no evidence, in humans, of substantial streaming during slow infraophthalmic intracarotid injections. Slow rates of infusion are as good as high rates for infraophthalmic intracarotid drug delivery. This is of special importance for drugs that are not tolerated at high injection rates. Moreover, infraophthalmic intracarotid chemotherapeutic infusion does not require special injectors or catheters.