IEEE Trans Ultrason Ferroelectr Freq Control. 2018 Oct;65(10):1743-1755. doi: 10.1109/TUFFC.2018.2847599. Epub 2018 Jun 14.
Feasibility of controlling bulk ultrasound (US) thermal ablation using echo decorrelation imaging was investigated in ex vivo bovine liver. The first of two ablation and control procedures used a sequence of constant-intensity sonication cycles, ceased when the minimum echo decorrelation within a control region of interest (ROI) exceeded a predetermined threshold. The second procedure used a variable-intensity sonication sequence, with spatially averaged decorrelation as the stopping criterion. US exposures and echo decorrelation imaging were performed by a linear image-ablate array. Based on preliminary experiments, control ROIs and thresholds for the minimum-decorrelation and average-decorrelation criteria were specified. Controlled trials for the minimum-decorrelation and average-decorrelation criteria were compared with uncontrolled trials employing 9 or 18 cycles of matching sonication sequences. Lesion dimensions, treatment times, ablation rates, and areas under receiver operating characteristic curves were statistically compared. Successfully controlled trials using both criteria required significantly shorter treatment times than corresponding 18-cycle treatments, with better ablation prediction performance than uncontrolled 9-cycle and 18-cycle treatments. Either control approach resulted in greater ablation rate than corresponding 9-cycle or 18-cycle uncontrolled approaches. A post hoc analysis studied the effect of exchanging control criteria between the two series of controlled experiments. For either group, the average time needed to exceed the alternative decorrelation threshold approximately matched the average duration of successfully controlled experimental trials. These results indicate that either approach, using minimum-decorrelation or average-decorrelation criteria, is feasible for control of bulk US ablation. In addition, use of a variable-intensity sonication sequence for bulk US thermal ablation can result in larger ablated regions compared to constant-intensity sonication sequences.
应用回声去相关成像来控制体超声（US）热消融的可行性已在离体牛肝中进行了研究。两个消融和控制程序中的第一个程序使用一系列恒定强度的超声循环，当控制感兴趣区域（ROI）内的最小回声去相关超过预定阈值时停止。第二个程序使用可变强度的超声序列，以空间平均去相关作为停止标准。US 暴露和回声去相关成像由线性图像消融阵列完成。基于初步实验，指定了控制 ROI 和最小去相关和平均去相关标准的阈值。与使用匹配的超声序列的 9 或 18 个循环的未控制试验相比，对最小去相关和平均去相关标准进行了受控试验。比较了病变尺寸、治疗时间、消融率和受试者工作特征曲线下面积的统计学差异。使用两种标准成功控制的试验所需的治疗时间明显短于相应的 18 个周期治疗，且比未控制的 9 个周期和 18 个周期治疗具有更好的消融预测性能。两种控制方法的消融率均大于相应的 9 个周期或 18 个周期未控制方法。事后分析研究了两种系列控制实验之间控制标准的交换效果。对于任一小组，超过替代去相关阈值所需的平均时间大约与成功控制的实验试验的平均持续时间相匹配。这些结果表明，两种方法，使用最小去相关或平均去相关标准，都可以用于控制体超声消融。此外，与恒定强度超声序列相比，使用可变强度超声序列进行体超声热消融可导致更大的消融区域。
