Mohamedkhan Shybi, Hindocha Sumeet, de Boisanger James, Millard Thomas, Welsh Liam, Rich Philip, MacKinnon Andrew D, Williams Nicholas, Sharma Bhupinder, Rosenfelder Nicola, Minchom Anna
Royal Marsden Hospital, Downs Rd., Sutton SM2 5PT, UK.
Royal Marsden Hospital, Fulham Rd., London SW3 6JJ, UK.
Cancers (Basel). 2024 Mar 20;16(6):1218. doi: 10.3390/cancers16061218.
Brain metastases are common in lung cancer and increasingly treated using targeted radiotherapy techniques such as stereotactic radiosurgery (SRS). Using MRI, post-SRS changes may be difficult to distinguish from progressive brain metastasis. Contrast clearance analysis (CCA) uses T1-weighted MRI images to assess the clearance of gadolinium and can be thus used to assess vascularity and active tumours.
We retrospectively assessed CCAs in 62 patients with non-small cell lung cancer (NSCLC) undergoing 104 CCA scans in a single centre.
The initial CCA suggested the aetiology of equivocal changes on standard MRI in 80.6% of patients. In all patients whose initial CCA showed post-SRS changes and who underwent serial CCAs, the initial diagnosis was upheld with the serial imaging. In only two cases of a presumed progressive tumour on the initial CCA, subsequent treatment for radionecrosis was instigated; a retrospective review and re-evaluation of the CCAs show that progression was reported where a thin rim of rapid contrast clearance was seen, and this finding has been subsequently recognised as a feature of post-treatment change on CCAs. The lack of concordance with CCA findings in those who underwent surgical resection was also found to be due to the over-reporting of the thin blue rim as disease in the early cases of CCA use and, in three cases, potentially related to timelines longer than 7 days prior to surgery, both factors being unknown during the early implementation phase of CCA at our centre but subsequently learned.
Our single-centre experience shows CCA to be feasible and useful in patients with NSCLC in cases of diagnostic uncertainty in MRI. It has helped guide treatment in the majority of patients, with subsequent outcomes following the implementation of the treatment based on the results, suggesting correct classification. Recommendations from our experience of the implementation include the careful consideration of the thin rim of the rapid contrast clearance and the timing of the CCA prior to surgery for suspected brain metastasis progression.
脑转移瘤在肺癌中很常见，越来越多地采用立体定向放射外科（SRS）等靶向放疗技术进行治疗。使用磁共振成像（MRI）时，SRS后的变化可能难以与进展性脑转移瘤区分开来。对比剂清除分析（CCA）利用T1加权MRI图像评估钆的清除情况，因此可用于评估血管情况和活性肿瘤。
我们回顾性评估了在单一中心接受104次CCA扫描的62例非小细胞肺癌（NSCLC）患者的CCA情况。
初始CCA提示80.6%的患者标准MRI上的模糊变化病因。在所有初始CCA显示SRS后变化且接受了系列CCA检查的患者中，初始诊断通过系列成像得以维持。仅在初始CCA显示为疑似进展性肿瘤的两例患者中，随后启动了放射性坏死治疗；对CCA的回顾性复查和重新评估显示，报告的进展情况是在可见快速对比剂清除的薄边缘处，而这一发现随后被确认为CCA上治疗后变化的一个特征。还发现，接受手术切除的患者中与CCA结果不一致是由于在早期使用CCA的病例中，薄蓝边被过度报告为疾病，以及在三例病例中，可能与手术前超过7天的时间线有关，这两个因素在我们中心CCA早期实施阶段均未知，但后来了解到了。
我们的单中心经验表明，在MRI诊断存在不确定性的NSCLC患者中，CCA是可行且有用的。它帮助指导了大多数患者的治疗，基于结果实施治疗后的后续结果表明分类正确。我们实施经验的建议包括，对于疑似脑转移瘤进展的情况，要仔细考虑快速对比剂清除的薄边缘以及手术前CCA的时间。
