Intratumoral vessel caliber and microvascular density in hepatocellular carcinoma

Abstract Purpose It is generally acknowledged that tumor vascularity, caliber, and quantity play a large role in effective locoregional treatment with particle embolization. To date, little has been documented in terms of actual measurements of arterial caliber and quantity (a.k.a. microvascular density) within hepatocellular carcinoma (HCC). The goal of this study was directly to measure intratumoral caliber and micro-vessel densities within HCCs. Methods 29 explanted HCCs were randomly retrieved from the pathology archives; 20 tumors (from 20 patients) with no-to-minimal necrosis on gross evaluation were selected and evaluated histopathologically. 1639 arteries were quantified and measured. Results Measurements, with corrective adjustments for the tissue attenuation secondary to pathology preparation, demonstrated the arterial caliber to vary between 6.4 and 281.86 µm, with 60.7% of vessels smaller than 20 µm, 80.29% smaller than 30 µm, and 88.95% smaller than 40 µm. The microvascular densities varied from 13 to 222 arteries per 13.5-mm 2 region of interest on a 4-µm-thick section. Conclusion Tumor vascularity plays a significant role in particle size selection in transarterial embolization for treatment of HCC. Appropriate particle size must be chosen to ensure maximal ischemia and decrease risk of adverse outcomes. The reported distribution of arterial caliber and density may serve as a guide for interventional radiologist performing particle embolization of HCC.