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Vascular and Interventional Radiology

E2257. Diagnosis and Clinical Implications of Hepatic Arterial Variants in 90Y Therapy

Shah J,  Meiers C,  Toskich B,  Lazarowicz M. University of Florida, Gainesville, FL

Address correspondence to L. Thornton (thorlm@radiology.ufl.edu)

Background Information: Yttrium-90 is an intraarterial radiation therapy, which has been increasingly administered over the past decade for the treatment of primary and metastatic liver neoplasms. Yttrium-90 can carry risk of significant toxicity if not appropriately administered to the tumor tissue of interest. All eligible patients undergo angiographic mapping and macroaggregated albumin administration. Because 45% of patients have variant anatomy, this procedural planning decreases toxicity to unintended hepatic arteries. The interventionalist and diagnostic radiologist must be able to recognize vascular variants that may exist in order to avoid unneeded toxicity, which may increase the chances of morbidity and decrease total tumor dose.

Educational Goals/Teaching Points: Participants will become familiar with the cross-sectional and angiographic appearances of the most common variants of the left hepatic circulation and the most common variants of the right hepatic circulation. Common pearls and pitfalls of identifying variant anatomy are presented. We demonstrate the benefits of cone beam CT to understand the potential complications that can arise from embolization of unrecognized variants.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: Variants can arise from either the right or left hepatic circulation. Nontarget radioembolization of these arteries increase rates of complications including duodenal ulcers, gastritis, cystitis, and dermatitis. Common variants include the gastroduodenal artery, cystic artery, falciform artery, left and right gastric artery, and left and right inferior phrenic among others. Angiographic evaluation may not always be sufficient to diagnose variants because of distortion of expected anatomy secondary to tumor neovascularity and cirrhosis. Therefore, familiarity with the course of these vessels on diagnostic cross-sectional imaging and intraprocedural investigation with cone beam CT is imperative. After review of this exhibit, the radiologist will feel more confident in distinguishing normal segmental arterial anatomy and those variants which should be excluded from therapy.

Conclusion: Recognizing hepatic arterial variants on diagnostic cross-sectional imaging as well as angiographically is critical to decreasing complication rates in in 90Y candidates. Familiarization with common variants and knowledge of useful tools such as cone beam CT may avoid potentially devastating side effects and ineffectual tumor dosing.