Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
STIMULATE-Solution Centre for Image Guided Local Therapies, Magdeburg, Germany.
Int J Hyperthermia. 2022;39(1):1387-1396. doi: 10.1080/02656736.2022.2138987.
To develop and evaluate susceptibility corrected 2D proton resonance frequency (PRF)-based magnetic resonance (MR)-thermometry for the accurate assessment of the ablation zone of hepatic microwave ablation (MWA).
Twelve hepatic MWA were performed in five LEWE minipigs with human-like fissure-free liver. Temperature maps during ablation of PRF-based MR-thermometry were corrected by modeling heat induced susceptibility changes. Ablation zones were determined using cumulative equivalent minutes at 43 °C (CEM43) as tissue damage model. T1 weighted (w) post-ablation contrast-enhanced (CE) MR-imaging and manually segmented postmortem histology were used for validation. The agreement of uncorrected (raw) and susceptibility corrected (corr) MR-thermometry with T1w post-ablation CE MR-imaging and histology was evaluated. The Wilcoxon-signed rank test and Bland-Altman analysis were applied.
With the susceptibility corrected MR-thermometry a significantly increased dice coefficient (raw: 77% vs. corr: 83%, < 0.01) and sensitivity (raw: 72% vs. corr: 82%, < 0.01) was found for the comparison to T1w-CE imaging as well as histopathology (dice coefficients: raw: 76% vs. corr: 79%, < 0.001; sensitivity: raw: 72% vs. corr: 74%, < 0.001). While major axis length was significantly increased (7.1 mm, < 0.001) and minor axis length significantly decreased (2.2 mm, < 0.001) in uncorrected MR-thermometry compared to T1w-CE MR-imaging, no significant bias was found after susceptibility correction.
Using susceptibility corrected 2D PRF-based MR-thermometry to predict the ablation zones of hepatic MWA provided a good agreement in comparison to T1w post-ablation CE MR-imaging and histopathology.
开发并评估基于二维质子共振频率（PRF）的磁化率校正磁共振（MR）测温技术，以准确评估肝部微波消融（MWA）的消融区域。
在 5 只具有无裂隙人肝脏的 LEWE 小型猪中进行了 12 次肝部 MWA。通过建模热诱导磁化率变化来校正 PRF 基于 MR 测温过程中的温度图。使用累积等效 43°C 分钟数（CEM43）作为组织损伤模型来确定消融区域。T1 加权（w）消融后对比增强（CE）MR 成像和手动分割的离体组织学用于验证。评估未校正（原始）和磁化率校正（校正）MR 测温与 T1w 消融后 CE MR 成像和组织学的一致性。应用 Wilcoxon 符号秩检验和 Bland-Altman 分析。
使用磁化率校正的 MR 测温技术，与 T1w-CE 成像和组织病理学相比，显著提高了 Dice 系数（原始：77%比校正：83%，<0.01）和敏感性（原始：72%比校正：82%，<0.01）（Dice 系数：原始：76%比校正：79%，<0.001；敏感性：原始：72%比校正：74%，<0.001）。虽然与 T1w-CE MR 成像相比，未校正的 MR 测温中主要轴长度显著增加（7.1mm，<0.001），次要轴长度显著减小（2.2mm，<0.001），但在磁化率校正后未发现明显偏差。
使用基于二维 PRF 的磁化率校正磁共振测温技术来预测肝部 MWA 的消融区域，与 T1w 消融后 CE MR 成像和组织病理学相比，具有较好的一致性。
