Time-related changes of radiofrequency ablation lesion in the normal rabbit liver: Findings of magnetic resonance imaging and histopathology
Time-related changes of radiofrequency ablation lesion in the normal rabbit liver: Findings of magnetic resonance imaging and histopathology
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DOI：
10.1097/01.rli.0000073447.32361.b3
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发表时间：
2003-08-01
影响因子：
6.7
通讯作者：
Yamada, S
中科院分区：
文献类型：
--
作者：
Tsuda, M;Rikimaru, H;Yamada, S
基本原理和目标：目的：研究正常肝脏射频消融（RFA）后时间相关的磁共振成像（MRI）和组织病理学改变。方法：在超声引导下，对22只家兔进行射频消融（RFA）。最初以10 W施加射频功率，每分钟增加5 W，直到射频功率“滚降”发生。在RFA后5周（n = 6）、2周（n = 6）、4周（n = 6）和12周（n = 4）对家兔进行死后MRI检查。采用自旋回波（SE）T1加权像（WI）（TR/TE=500/12）和快速SE T2加权像（TR/TE = 3500/99）。切除肝脏标本并进行常规组织学研究。结果：MRI测量的病灶直径与肝组织病理学检查结果具有良好的相关性（P < 0.05）。RFA后3天T1/T2-WI上凝固区呈4个层状结构中的2个，2 ~ 4周T1/T2-WI上凝固区呈3个层状结构中的2个。术后12周，凝固区T1-WI信号增强，T2-WI仍呈2层片状，与术后2 ~ 4周相同。结论：兔肝RFA病灶的MRI表现为层状改变，其病理改变与时间相关，肝内血窦扩大、边缘纤维组织增生、肝细胞变性等病理改变可能与MRI的层状改变和信号强度变化有关。了解病变的区域结构有助于对随访MRI的评价。
Rationale and Objectives: To study time-related magnetic resonance imaging (MRI) and histopathological findings after radiofrequency ablation (RFA) in the normal liver.Methods: Under ultrasound guidance, REA was performed in 22 rabbits with a 15-gauge expandable probe inserted into the liver. The RF power was applied at 10 W initially with a 5-W increment every minute until RF power "roll-off" occurred. The rabbits subjected to postmortem MRI at Mays (n = 6), 2 weeks (n = 6), 4 weeks (n = 6), and 12 weeks (n = 4) after RFA. Spin-echo (SE) T-1-weighted image (WI) (TR/TE=500/12) and fast SE T2-WI (TR/TE = 3500/99) were obtained. The liver specimens were excised and processed for conventional histologic study. The MRI and pathologic findings were compared qualitatively and quantitatively.Results: The lesion diameters measured with MRI and liver specimen were well correlated (P < 0.05). The coagulated regions presented 2 of 4 laminar patterns on T1/T2-WI 3 days after RFA, and 2 of 3 laminar patterns on T1/T2-WI 2 to 4 weeks after RFA. 12 weeks after REA, the signal intensity in coagulated regions increased on T1-WI with a 2-laminar pattern still visible on T2-WI, the same as that of 2 to 4 weeks. The observed pathologic changes (enlarged sinusoids, marginal fibrous tissue and hepatocyte degeneration) could be responsible for the MRI laminar patterns and signal intensity changes.Conclusion: The time-related pathologic changes of RFA lesions in rabbit livers can be reflected as laminar patterns on MR images. Understanding of the zone structure of the lesions is useful for the evaluation of follow-up MRI.