a Interventional Oncology Service , University College Hospital , London , UK.
b Hepatopancreatobiliary and Liver Transplant Surgery Unit, University Department of Surgery , Royal Free London NHS Foundation Trust and University College London , London , UK.
Int J Hyperthermia. 2018 Nov;34(7):1114-1120. doi: 10.1080/02656736.2017.1400119. Epub 2017 Nov 21.
Microwave ablation (MWA) has been proposed to suffer less from the heat sink effect compared to radiofrequency ablation but has been reported to cause extension of the ablation zone along intrahepatic vessels in clinical practice. To study this effect in detail, eight fresh porcine livers were perfused in an ex vivo organ perfusion system. Livers were perfused with oxygenated, O-positive human blood at 37 °C. Perfusion was discontinued immediately before ablation in the non-perfused group (n = 4) whilst in the perfused group (n = 4) perfusion was maintained during MWA (140 W X 2 min). Large intrahepatic vessels (> 6 mm) were avoided using ultrasound. MWA zones were bisected within 30 min of perfusion termination and sections were fixed in formalin and stained with H&E and NADH to assess cell viability. Magnetic resonance imaging (MRI) was performed on two livers (one perfused, one non-perfused) to provide imaging correlation before sectioning. Twenty-one out of a total of 30 MW ablation zones (70%) showed extension of the ablation zone along a vessel. There was no statistically significant difference (p = 1) in the incidence of ablation zone extension between perfused (9/13, 69%) and non-perfused organs (12/17, 71%). MRI also demonstrated ablation zone extension along blood vessels correlating with macroscopy in two livers. NADH staining also confirmed extension of the ablation zone. Liver MWA appears to be commonly associated with propagated thermal injury along adjacent vessels and occurs independent of active blood flow. In order to avoid possible complications through non-target tissue injury, this effect requires further investigation.
微波消融（MWA）相较于射频消融而言，热沉降效应较小，但据报道在临床实践中会导致消融区域沿着肝内血管延伸。为了详细研究这种效应，我们将 8 个新鲜猪的肝脏在离体器官灌注系统中进行灌注。肝脏在 37°C 下用充氧的 O 型阳性人血进行灌注。在未灌注组（n=4）中，在消融前立即停止灌注，而在灌注组（n=4）中，在 MWA（140W X 2 分钟）期间保持灌注。使用超声避开大的肝内血管（>6mm）。在灌注停止后 30 分钟内将 MWA 区域切成两半，并将切片固定在福尔马林中，用 H&E 和 NADH 染色以评估细胞活力。对两个肝脏（一个灌注，一个未灌注）进行磁共振成像（MRI），在切片前提供成像相关性。在总共 30 个 MWA 消融区域中，有 21 个（70%）显示出沿着血管延伸的消融区域。灌注（9/13，69%）和未灌注器官（12/17，71%）之间消融区域延伸的发生率没有统计学上的显著差异（p=1）。MRI 还显示在两个肝脏中，消融区域沿着血管延伸与大体观察结果相吻合。NADH 染色也证实了消融区域的延伸。肝脏 MWA 似乎经常与相邻血管的传播性热损伤有关，并且与活跃的血流无关。为了避免通过非靶组织损伤引起的可能并发症，需要进一步研究这种效应。
