Background:The diagnosis and treatment of small hepatocellular carcinoma (HCC) play a vital role in the prognosis of patients with HCC.The purpose of our study was to evaluate angio-computed tomography (angio-CT)-guided immediate lipiodol CT (a CT scan performed immediately after transarterial chemoembolization [TACE]) in the diagnosis of potential HCCs ≤1 cm in diameter.Methods:This study retrospectively analyzed 31 patients diagnosed with HCCs after routine imaging (contrast-enhanced CT or magnetic resonance imaging) or pathologic examinations with undefined or undetermined tumor lesions (diameter ≤1 cm) from February 2016 to September 2016.After TACE guided by digital subtraction angiography of the angio-CT system,potential HCC lesions with a diameter ≤1 cm were diagnosed by immediate lipiodol CT.The number of well-demarcated lesions was recorded to calculate the true positive rate.The correlation between the number of small HCCs detected by immediate lipiodol CT and the size of HCC lesions (diameter ＞1 cm) diagnosed preoperatively was analyzed 1 month after TACE.A paired t-test was used to analyze differences in liver function.Pearson analysis was used to analyze correlation.Chi-square test was used to compare the rates.Results:Fifty-eight lesions were detected on preoperative routine imaging examinations in 31 patients including 15 lesions with a diameter ≤ 1 cm.Ninety-one lesions were detected on immediate lipiodol CT,of which 48 had a diameter≤ 1 cm.After 1 month,CT showed that 45 lesions had lipiodol deposition and three lesions had lipiodol clearance.Correlation analysis showed that the number of small HCCs detected by lipiodol CT was positively correlated with the size of HCC lesions diagnosed by conventional imaging examination (R2 =0.54,P ＜ 0.05).Conclusion:Immediate lipiodol CT may be a useful tool in the diagnosis of potential HCC lesions with a diameter of≤1 cm.