Division of Thoracic Imaging and Intervention, Department of Radiological Sciences, UCLA Medical Center, 757 Westwood Plaza, Suite 1621, Los Angeles, CA 90095, USA.
Radiographics. 2012 Jul-Aug;32(4):947-69. doi: 10.1148/rg.324105181.
Radiofrequency ablation (RFA) is used to treat pulmonary malignancies. Although preliminary results are suggestive of a survival benefit, local progression rates are appreciable. Because a patient can undergo repeat treatment if recurrence is detected early, reliable post-RFA imaging follow-up is critical. The purpose of this article is to describe (a) an algorithm for post-RFA imaging surveillance; (b) the computed tomographic (CT) appearance, size, enhancement, and positron emission tomographic (PET) metabolic activity of the ablation zone; and (c) CT, PET, and dual-modality imaging with PET and CT (PET/CT) features suggestive of partial ablation or tumor recurrence and progression. CT is routinely used for post-RFA follow-up. PET and PET/CT have emerged as auxiliary follow-up techniques. CT with nodule densitometry may be used to supplement standard CT. Post-RFA follow-up was divided into three phases: early (immediately after to 1 week after RFA), intermediate (>1 week to 2 months), and late (>2 months). CT and PET imaging features suggestive of residual or recurrent disease include (a) increasing contrast material uptake in the ablation zone (>180 seconds on dynamic images), nodular enhancement measuring more than 10 mm, any central enhancement greater than 15 HU, and enhancement greater than baseline anytime after ablation; (b) growth of the RFA zone after 3 months (compared with baseline) and definitely after 6 months, peripheral nodular growth and change from ground-glass opacity to solid opacity, regional or distant lymph node enlargement, and new intrathoracic or extrathoracic disease; and (c) increased metabolic activity beyond 2 months, residual activity centrally or at the ablated tumor, and development of nodular activity.
射频消融 (RFA) 用于治疗肺部恶性肿瘤。尽管初步结果表明有生存获益，但局部进展率仍相当可观。因为如果早期发现复发，患者可以接受重复治疗，因此可靠的 RFA 后影像学随访至关重要。本文的目的是描述：(a)RFA 后影像学监测的算法；(b)消融区的 CT 表现、大小、增强和正电子发射断层扫描 (PET) 代谢活性；以及(c)提示部分消融或肿瘤复发和进展的 CT、PET 和 PET/CT 双重模态成像的特征。CT 常规用于 RFA 后随访。PET 和 PET/CT 已成为辅助随访技术。CT 结节密度测定可能用于补充标准 CT。RFA 后随访分为三个阶段：早期（RFA 后立即至 1 周）、中期（>1 周至 2 个月）和晚期（>2 个月）。提示残留或复发疾病的 CT 和 PET 成像特征包括：(a) 消融区对比剂摄取增加（动态图像上>180 秒），结节增强大于 10mm，任何中央增强大于 15HU，消融后任何时间增强大于基线；(b)RFA 区在 3 个月（与基线相比）后且在 6 个月后肯定增大，周围结节增大且从磨玻璃密度变为实变密度，区域性或远处淋巴结肿大以及新的胸内或胸外疾病；以及(c)2 个月后代谢活性增加，中央或消融肿瘤处仍有活性，以及结节活性的发展。
