Portal venous or late (equilibrium) phase washout is one of the well-known major imaging features of hepatocellular carcinoma (HCC). However, these two washouts stand for distinct intratumoral pathophysiological states and should be considered separately. Positive portal venous phase (PVP) washout has been shown to be related to high grade HCC, poor post operative survival rate, and positive PD-L1 or VETC. In contrast, there is indirect evidence that negative washout at equilibrium or late phase (EqP) may be related to biliary/stem cell subtype, which is biologically aggressive, and associated with an immune hot tumor microenvironment. Thus, although these two washouts represent different intratumoral pathophysiological conditions, both are closely related to biological aggressiveness or tumor microenvironment, which may be associated with the response to systemic therapies or post-surgical survival. In contemporary practice, gadoxetate-enhanced MRI restricts washout assessment in the PVP, whereas extracellular agent CT permits assessment in both the PVP and EqP; accordingly, this review addresses PVP washout on CT or extracellular agent MRI, PVP washout on gadoxetate-enhanced MRI, and EqP washout on CT. When washout information is integrated with other clinico-radiological features, more precise prediction of patient survival or response to systemic therapies would become possible in the future.
门静脉期或延迟（平衡）期廓清是肝细胞癌（HCC）公认的主要影像学特征之一。然而，这两种廓清代表不同的瘤内病理生理状态，应予以区分考量。门静脉期（PVP）阳性廓清已被证实与高级别HCC、术后低生存率及PD-L1或VETC阳性相关。相反，间接证据表明平衡期或延迟期（EqP）无廓清可能与胆管/干细胞亚型相关，该亚型具有生物学侵袭性，并与免疫热肿瘤微环境相关。因此，尽管这两种廓清反映不同的瘤内病理生理状态，但均与生物学侵袭性或肿瘤微环境密切相关，这可能影响系统治疗反应或术后生存。在当前临床实践中，钆塞酸增强MRI仅能评估PVP期廓清，而细胞外对比剂CT可同时评估PVP和EqP期廓清；据此，本综述将分别探讨CT或细胞外对比剂MRI的PVP廓清、钆塞酸增强MRI的PVP廓清以及CT的EqP廓清。未来若将廓清信息与其他临床放射学特征整合，将有望更精准预测患者生存期及系统治疗反应。
肿瘤(癌症)患者之家