先进的 CT 技术在肝微波消融区域监测和随访中的应用。

Advanced CT techniques for hepatic microwave ablation zone monitoring and follow-up.

机构信息

Department of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792, USA.

Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.

出版信息

Abdom Radiol (NY). 2022 Aug;47(8):2658-2668. doi: 10.1007/s00261-021-03333-z. Epub 2021 Nov 3.

DOI:10.1007/s00261-021-03333-z

PMID:34731282

Abstract

PURPOSE

To evaluate utility of advanced CT techniques including HighlY constrained back-projection and dual-energy CT for intra- and post-procedure hepatic microwave ablation zone monitoring.

METHODS

8 hepatic microwave ablations were performed in 4 adult swine (5 min/65 W). Low-dose routine CECT and dual-energy CT images were obtained every 1 min during ablation. Images were reconstructed ± HYPR. Image quality and dose metrics were collected. 21 MWA were performed in 4 adult swine. Immediate post-procedure CECT was performed in the arterial, portal venous, and delayed phases using both routine and DECT imaging with full-dose weight-based IV contrast dosing. An additional 16 MWA were subsequently performed in 2 adult swine. Immediate post-procedure CT was performed with half-dose IV contrast using routine and DECT. 12 patients (10 M/2F, mean age 62.4 yrs) with 14 hepatic tumors (4 HCC, 10 metastatic lesions) treated with MWA were prospectively imaged with DECT 1 month post-procedure. 120 kV equivalent images were compared to DECT [51 keV, iodine material density]. Image quality and dose metrics were collected.

RESULTS

Gas created during MWA led to high CNR in all intraprocedural CT datasets. Optimal CNRs were noted at 4 min with CNR 6.7, 15.5,15.9, and 21.5 on LD-CECT, LD-CECT + HYPR, DECT, and DECT + HYPR, respectively (p < 0.001). Image quality scores at 4 min were 1.8, 2.8, 2.4, and 3, respectively (p < 0.001). Mean radiation dose (CTDI) was eightfold higher for the DECT series. For swine, post-procedural DECT images (IMD/51 keV) showed improved CNR compared to routine CT at all time points with full and with reduced dose contrast (CNR 4.6, 3.2, and 1.5, respectively, at half-contrast dose, p < 0.001). For human subjects, the 51 keV and IMD images showed higher CNRs (5.8, 4.8 vs 4.0, p < 0.001) and SNRs (3.7, 5.9 vs 2.8). Ablation zone sharpness was improved with DECT (routine 3.0 ± 0.7, DECT 3.5 ± 0.5). Diagnostic confidence was higher with DECT (routine 2.3 ± 0.9, DECT 2.6 ± 0.8). Mean DLP for DECT was 905.7 ± 606 mGy-cm, CTDI 37.5 ± 21.2 mGy, and effective dose 13.6 ± 9.1 mSv, slightly higher than conventional CT series.

CONCLUSION

Advanced CT techniques can improve CT image quality in peri-procedural hepatic microwave ablation zone evaluation.

摘要

目的

评估高级 CT 技术在肝微波消融术（MWA）治疗过程中和治疗后的监测中的应用价值，这些技术包括高约束反向投影（HYPR）和双能 CT。

方法

在 4 只成年猪中进行了 8 次 MWA（5 分钟/65 瓦）。在消融过程中，每 1 分钟进行一次低剂量常规 CT 增强扫描和双能 CT 扫描。图像分别进行常规重建和 HYPR 重建。收集图像质量和剂量指标。在 4 只成年猪中进行了 21 次 MWA。在动脉期、门静脉期和延迟期，使用常规和双能 CT 成像，对所有 MWA 均进行全剂量基于体重的静脉造影剂注射。随后，在 2 只成年猪中进行了 16 次 MWA，仅使用常规和双能 CT 成像，采用半剂量静脉造影剂。12 名（10 名男性/2 名女性，平均年龄 62.4 岁）患有 14 个肝肿瘤（4 个 HCC，10 个转移性病变）的患者，在 MWA 治疗后 1 个月接受前瞻性双能 CT 检查。120kV 等效图像与双能 CT [51keV，碘物质密度]进行比较。收集图像质量和剂量指标。

结果

MWA 过程中产生的气体导致所有术中 CT 数据集的 CNR 均很高。在 LD-CECT、LD-CECT+HYPR、DECT 和 DECT+HYPR 上，分别在 4 分钟时观察到最佳 CNR（分别为 6.7、15.5、15.9 和 21.5）（p<0.001）。在 4 分钟时，图像质量评分分别为 1.8、2.8、2.4 和 3（p<0.001）。DECT 系列的平均辐射剂量（CTDI）高 8 倍。对于猪，在所有时间点，使用全剂量和半剂量对比剂后，DECT 图像（IMD/51keV）显示出比常规 CT 更好的 CNR（分别为 4.6、3.2 和 1.5，p<0.001）。对于人类受试者，51keV 和 IMD 图像显示出更高的 CNR（5.8、4.8 比 4.0，p<0.001）和 SNR（3.7、5.9 比 2.8）。DECT 可提高消融区的清晰度（常规 CT 为 3.0±0.7，DECT 为 3.5±0.5）。DECT 可提高诊断信心（常规 CT 为 2.3±0.9，DECT 为 2.6±0.8）。DECT 的平均 DLP 为 905.7±606mGy-cm，CTDI 为 37.5±21.2mGy，有效剂量为 13.6±9.1mSv，略高于常规 CT 系列。