Characterization of acute and subacute radiofrequency ablation lesions with nonenhanced magnetic resonance imaging
Characterization of acute and subacute radiofrequency ablation lesions with nonenhanced magnetic resonance imaging
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DOI：
10.1016/j.hrthm.2006.10.019
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发表时间：
2007-02-01
期刊：
影响因子：
5.5
通讯作者：
Halperin, Henry
中科院分区：
文献类型：
--
作者：
Dickfeld, Timm;Kato, Ritsushi;Halperin, Henry
背景磁共振成像（MRI）具有可视化射频（RF）消融的潜力，射频消融已成为治疗许多心律失常的首选策略。然而，射频消融后的MRI模式还没有得到很好的investigated. ObjectiveThe本研究的目的是定义的特征性外观和时间和能量的影响，对noncontrast-enhanced MRI的RF ablation.METHODS使用功率控制，冷尖消融系统，RF消融病变（5-50 W，45秒）在10只杂种犬的右心室心外膜。结果消融后30 min ~ 12 h，T2、T1加权成像均能显示病灶，且与大体解剖和组织病理学结果相对照。T2图像更加一致，显示了特征性的椭圆形高信号核心（对比度噪声比[CNR] = 18.9 +/- 18.4），周围有0.5 mm的低强度边缘，在组织病理学上分别对应于中央组织坏死和过渡区。T1图像显示信号强度增加不太明显（CNR = 9.6 +/- 7.4），无周围边缘。病变大小和外观定义明确，在12小时随访期间无变化（方差分析）。CNR与施加的射频能量无关，并允许在所有时间点准确评估射频消融（T2和T1图像分别为r = 0.87和r = 0.83）。结论MRI平扫可准确评价射频消融术后12 h内的病灶形态和病理变化，对射频消融术后12 h内的病理变化有较好的预测价值。这一发现证实了MRI在电生理消融术期间引导和评价射频应用的可能机制。
BACKGROUND Magnetic resonance imaging (MRI) has the potential to visualize radiofrequency (RF) ablations, which have become the preferred strategy for treatment of many arrhythmias. However, MRI patterns after RF ablation have not been well investigated.OBJECTIVE The purpose of this study was to define the characteristic appearance and the effect of time and energy on noncontrast-enhanced MRI of RF ablation.METHODS Using a power-controlled, cooled-tip ablation system, RF ablation Lesions (5-50 W for 45 seconds) were created on the right ventricular epicardium in 10 mongrel dogs. T1- and T2-weighted MR images were obtained during 12-hour follow-up and compared with gross anatomy and histopathology.RESULTS Lesions were successfully visualized with T2- and T1-weighted images 30 minutes to 12 hours after RF ablation. T2 images were more consistent and displayed a characteristic elliptical, high-signal core (contrast-to-noise-ratio [CNR] = 18.9 +/- 18.4) with a surrounding 0.5-mm tow-intensity rim that on histopathology corresponded to the central tissue necrosis and the transition zone, respectively. T1 images showed a less remarked increase in signal intensity (CNR = 9.6 +/- 7.4) without a surrounding rim. Lesion size and appearance were well defined and unchanged during the 12-hour follow-up (analysis of variance). CNR was independent of applied RF energy and allowed accurate assessment of RF ablation at all time points (r = 0.87 and r = 0.83 for T2 and T1 images, respectively). Transmural Lesions, interlesional gaps, and intralesional pathology could be reliably predicted in >90%.CONCLUSION Noncontrast-enhanced MRI allows accurate assessment of RF ablation and its intratesional pathology during 12-hour follow-up. This finding confirms a possible rote of MRI in guiding and evaluating RF application during electrophysiologic ablation procedures.