冷热交替消融正常兔肝的影像学与病理学研究

Imaging findings and pathological changes of rabbit liver after alternated cooling and heating ablation

目的 探讨正常兔肝冷热交替消融后消融灶的动态影像学和病理学变化。方法 对20只正常兔肝进行冷热交替消融。消融后1、3、7、14天行CT和CEUS，之后各处死5只兔，观察消融灶的病理学改变。结果 消融灶中心呈凝固性坏死。消融后7天内，坏死灶周围组织充血水肿和急性炎细胞浸润，CT平扫为低或等密度灶，常规超声为低回声为主的混合回声区；增强后均表现为无强化坏死灶和动脉期周边环状增强。消融后7~14天，坏死灶周围组织充血水肿好转，有纤维组织增生、慢性炎细胞浸润及钙化形成，表现为环形强化逐渐减轻消失，消融灶缩小。结论 冷热交替消融可在正常兔肝中产生凝固坏死灶；CT增强扫描和CEUS能有效反映不同时期肝脏消融灶的病理学变化，准确显示消融灶范围。

Objective To explore the dynamic changes of imaging and pathology after alternated cooling and heating ablation in normal rabbit livers. Methods Twenty normal rabbits underwent alternated cooling and heating ablation in livers and were monitored with CEUS and CT at 1, 3, 7 and 14 days after ablation. Five rabbits were sacrificed to observe the pathological changes of ablation lesions after imaging examination on each time points. Results Within 7 days after ablation, congestion and edema of tissue and acute inflammatory cells infiltration were found surrounding the central coagulation necrosis. Plain CT showed hypodense or isodense area, while routine ultrasound showed mainly hypoechoic mixed echo area. Enhanced CT and CEUS showed filling defect of contrast media in the ablated areas which were surrounded by ring enhancement on arterial phase. Seven to 14 days after ablation, congestion and edema around necrotic tissue decreased, and the ablation lesions also showed as extensive coagulative necrosis and surrounded infiltration by chronic inflammatory cells, fibroplasia and calcification. Follow-up imaging displayed that ablation areas shrunk correlating with time and fibrous repair. Conclusion Alternated cooling and heating ablation can produce coagulation necrosis in normal rabbit liver. Enhanced CT and CEUS can well reflect pathological changes of liver lesions of different periods and accurately demonstrate the range of lesions.