Department of Urology, Radboud University Medical Center, P.O. box 9101, 6500 HB, Nijmegen, The Netherlands.
Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
Cardiovasc Intervent Radiol. 2020 Nov;43(11):1661-1670. doi: 10.1007/s00270-020-02634-y. Epub 2020 Sep 15.
To validate a simulation environment for virtual planning of percutaneous cryoablation of renal tumors.
Prospectively collected data from 19 MR-guided procedures were used for validation of the simulation model. Volumetric overlap of the simulated ablation zone volume (Σ) and the segmented ablation zone volume (S; assessed on 1-month follow-up scan) was quantified. Validation metrics were DICE Similarity Coefficient (DSC; the ratio between twice the overlapping volume of both ablation zones divided by the sum of both ablation zone volumes), target overlap (the ratio between the overlapping volume of both ablation zones to the volume of S; low ratio means S is underestimated), and positive predictive value (the ratio between the overlapping volume of both ablation zones to the volume of Σ; low ratio means S is overestimated). Values were between 0 (no alignment) and 1 (perfect alignment), a value > 0.7 is considered good.
Mean volumes of S and Σ were 14.8 cm (± 9.9) and 26.7 cm (± 15.0), respectively. Mean DSC value was 0.63 (± 0.2), and ≥ 0.7 in 9 cases (47%). Mean target overlap and positive predictive value were 0.88 (± 0.11) and 0.53 (± 0.24), respectively. In 17 cases (89%), target overlap was ≥ 0.7; positive predictive value was ≥ 0.7 in 4 cases (21%) and < 0.6 in 13 cases (68%). This indicates S is overestimated in the majority of cases.
The validation results showed a tendency of the simulation model to overestimate the ablation effect. Model adjustments are necessary to make it suitable for clinical use.
验证用于经皮冷冻消融肾肿瘤虚拟规划的模拟环境。
前瞻性收集了 19 例 MR 引导下手术的资料，用于验证模拟模型。对模拟消融区域体积（Σ）和分割的消融区域体积（S；在 1 个月的随访扫描中评估）进行了容积重叠量化。验证指标包括 DICE 相似系数（DSC；两个消融区域重叠体积的两倍与两个消融区域体积之和的比值）、靶区重叠（两个消融区域重叠体积与 S 体积之比；比值较低意味着 S 被低估）和阳性预测值（两个消融区域重叠体积与 Σ 体积之比；比值较低意味着 S 被高估）。值在 0（无对齐）和 1（完美对齐）之间，大于 0.7 被认为是良好的。
S 和 Σ 的平均体积分别为 14.8 ± 9.9 cm 和 26.7 ± 15.0 cm。平均 DSC 值为 0.63（± 0.2），9 例（47%）大于 0.7。平均靶区重叠和阳性预测值分别为 0.88（± 0.11）和 0.53（± 0.24）。在 17 例（89%）中，靶区重叠大于 0.7；阳性预测值在 4 例（21%）中大于 0.7，在 13 例（68%）中小于 0.6。这表明 S 在大多数情况下被高估。
验证结果表明模拟模型有高估消融效果的趋势。需要进行模型调整使其适用于临床应用。
