Fig. 5

Two typical case demonstrations of perihilar cholangiocarcinoma. A–D Images from a 47-year-old male patient with pCCA. A, B The signal enhancement ratio (SER) before the initiation of hepatic arterial infusion chemotherapy (HAIC) was 1.39 [(709–297)/297]. C, D After two cycles of HAIC, the tumor shrank significantly in size, which corresponded to partial response according to RECIST 1.1. SER of the tumor decreased [SER = (498–221)/221 = 1.25; ΔSER = 1.39–1.25 = 0.14 > 0]. This patient was still alive, and the tumor did not progress by the time of last follow-up, with a survival time more than 83 months. E–H Images from a 60-year-old male patient with pCCA. E, F The SER before the initiation of HAIC was 0.59 [(148–93)/93]. G, H After two cycles of HAIC, the tumor did not change significantly in size, which corresponded to stable disease according to RECIST 1.1. SER of the tumor increased [SER = (168–102)/102 = 0.65; ΔSER = 0.59–0.65 = − 0.06 < 0]. The tumor progressed after 2 months following the initiation of HAIC. Although the subsequent HAIC with another regimen was performed, the patient died 5.4 months after the initiation of HAIC