兔VX-2肝肿瘤MRI表现和病理对照研究

目的:评价MRI对兔VX-2肝癌存活肿瘤、肿瘤坏死和出血的显示能力。方法:10只兔肝内接种VX-2肝癌后14 d行MRI扫描。检查后处死动物行病理检查。MRI表现与病理结果对照。结果:(1)MRI表现:10只兔共有病灶18个。病灶在SE T1WI上为低信号,T2WI上为不均匀高信号。动态增强早期病灶有不均匀强化,以环状强化为主,增强晚期仍见强化。(2)病理:所有标本均有不同程度的凝固性坏死。6个直径大于1．5 cm的病灶内见凝固性坏死伴出血。(3)MRI与病理对照,T1WI低信号为肿瘤组织、坏死; T2WI高信号为肿瘤组织、坏死伴出血,低信号为凝固性坏死。动态增强有强化区为肿瘤组织,无强化为坏死、出血。结论:(1)兔VX- 2肝癌可发生自发性凝固性坏死和出血等改变。(2)MRI,尤其是动态增强能准确显示兔VX-2肝癌的肿瘤组织、坏死和出血。

Comparative Study of MRI Manifestations and Pathology of VX-2 Rabbit Carcinoma

Objective: To evaluate the ability of MRI in the assessment of the tumor tissue, intra-tumoral necrosis and hemorrhage of the VX-2 rabbit tumor through the imaging-pathologic correlation. Methods: 10 rabbits were implanted in the liver with VX-2 tumor cells. MRI was performed at 14 days after implantation. All animals were sacrificed and the pathological examination was performed. MRI findings were compared with those of pathological examination. Results: (1) MRI manifestations:10 rabbits with 18 lesions were found on MRI images. All lesions were hypo-intensity on T1 WI images, and inhomogeneous hyper-intensity on T2WI. Inhomogeneous enhancement, prominently with ring enhancement was showed on the early-phase dynamic contrast scanning, and persisted on the delay-phase contrast scanning. (2) Pathologically, various degree of coagulation necrosis was found in all resected specimens. The area of necrosis located in the central of tumor or mixed with tumor tissue. Coagulation necrosis with hemorrhage was also found in 6 lesions with diameter more than 1. 5cm. (3) Radiologic-Pathologic correlation: Area of hypo-intense on T1 WI images corresponded to viable tumor tissue, coagulation necrosis or hemorrhage; area of hyper-intensity on T2 WI was viable tumor tissue and necrosis with hemorrhage, while area of hypo-intensity was coagulation necrosis. Area of enhancement on contrast scanning corresponded to viable tumor tissue, and area of no enhancement was coagulation necrosis and hemorrhage. Conclusion: (1) Spontaneous coagulation necrosis and hemorrhage usually occur in the rabbit VX-2 tumor. (2) MRI, especially the dynamic contrast scanning, can demonstrate accurately the viable tumor tissue, necrosis and hemorrhage.