Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10, P.O. Box 9101, 6525, Nijmegen, GA, Netherlands.
Department of Urology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, Nijmegen, GA, Netherlands.
Cancer Imaging. 2023 Mar 30;23(1):31. doi: 10.1186/s40644-023-00546-x.
To assess volumetric ablation margins derived from intraoperative pre- and post-ablation MRI after magnetic resonance imaging (MRI)-guided percutaneous cryoablation of renal tumors and explore its correlation with local treatment success.
Retrospective analysis was performed on 30 patients (mean age 69y) who underwent percutaneous MRI-guided cryoablation between May 2014 and May 2020 for 32 renal tumors (size: 1.6-5.1 cm). Tumor and ice-ball volumes were segmented on intraprocedural pre- and post-ablation MR images using Software Assistant for Interventional Radiology (SAFIR) software. After MRI-MRI co-registration, the software automatically quantified the minimal treatment margin (MTM),defined as the smallest 3D distance between the tumor and ice-ball surface. Local tumor progression (LTP) after cryoablation was assessed on follow-up imaging.
Median follow-up was 16 months (range: 1-58). Local control after cryoablation was achieved in 26 cases (81%) while LTP occurred in 6 (19%). The intended MTM of ≥5 mm was achieved in 3/32 (9%) cases. Median MTM was significantly smaller for cases with (- 7 mm; IQR:-10 to - 5) vs. without LTP (3 mm; IQR:2 to 4) (P < .001). All cases of LTP had a negative MTM. All negative treatment margins occurred in tumors > 3 cm.
Determination of volumetric ablation margins from intraoperative MRI was feasible and may be useful in predicting local outcome after MRI-guided renal cryoablation. In our preliminary data, an intraoperative MRI-derived minimal margin extending at least 1 mm beyond the MRI-visible tumor led to local control and this was more difficult to achieve in tumors > 3 cm. Ultimately, online margin analysis may be a valuable tool to intraoperatively assess therapy success, but larger prospective studies are needed to establish a reliable threshold for clinical use.
评估磁共振成像（MRI）引导下经皮冷冻消融治疗肾肿瘤后术中术前和术后 MRI 得出的容积消融边缘，并探讨其与局部治疗成功的关系。
回顾性分析了 2014 年 5 月至 2020 年 5 月期间接受经皮 MRI 引导下冷冻消融治疗的 30 例（平均年龄 69 岁）32 个肾肿瘤（大小：1.6-5.1cm）患者。使用 Software Assistant for Interventional Radiology（SAFIR）软件在术中术前和术后 MRI 上对肿瘤和冰球体积进行分割。MRI-MRI 配准后，软件自动量化最小治疗边缘（MTM），定义为肿瘤和冰球表面之间的最小 3D 距离。在随访影像学上评估冷冻消融后的局部肿瘤进展（LTP）。
中位随访时间为 16 个月（范围：1-58）。26 例（81%）冷冻消融后局部控制，6 例（19%）发生 LTP。32 例中，仅 3 例（9%）达到≥5mm 的预期 MTM。与无 LTP 相比，有 LTP 的 MTM 中位数明显较小（-7mm；IQR：-10 至-5）（P<.001）。所有 LTP 病例均有负 MTM。所有负治疗边缘均发生在>3cm 的肿瘤中。
从术中 MRI 确定容积消融边缘是可行的，可能有助于预测 MRI 引导下肾冷冻消融后的局部结果。在我们的初步数据中，术中 MRI 得出的最小边缘至少超出 MRI 可见肿瘤 1mm 可导致局部控制，而在>3cm 的肿瘤中更难实现。最终，在线边缘分析可能是术中评估治疗成功的有价值工具，但需要更大的前瞻性研究来建立用于临床的可靠阈值。
