A Patient-Adaptive, High MI Abdominal Scanner

一种患者自适应的高MI腹部扫描仪 我们建议构建一种快速、自动的自适应超声扫描仪并进行临床评估 调整系统控制以优化图像质量，并帮助超声医师选择良好的声学效果 窗户。我们假设，自适应优化和引导窗口选择图像的质量将 超过在常规扫描条件下采集的数据。我们将在修改后的 商业扫描仪在现实临床条件下对肝细胞癌的筛查。 优化的图像将具有快速和自适应地选择的发射功率、频率、焦深(S)、成像 模式(基波或谐波)和其他成像参数，并将在两个机械指数采集 (制造商的默认设置(MI=1.2)，“患者优化的”MI最高可达2.5)。在一个重要的 在患者子集中，我们之前的工作显示出显著的图像质量改善和深度增加 与MI水平增加相关的渗透率。我们在这份申请中展示的初步研究表明， 自动选择MI和其他成像参数的潜在临床益处。自动选择 如提议的那样，MI将实现声暴露的ALARA(尽可能低)原则。 目前，超声医生在肝细胞癌筛查过程中采集了数十个单独的图像，以供医生审查和 文件。一些已发表的研究和我们的经验表明，超声波医师使用的是 控制相当节制，特别是发射功率电平控制。自动选择成像 声学窗口的参数和指导选择不仅应该改善图像质量和深度 穿透性，但也应该提高扫描程序的效率，并减少超声波检查员的 符合人体工程学的挑战。我们的初步结果和临床文献也证明了声学的重要性。 改善图像质量的窗口选择以及这项任务面临的物理挑战 超音波医生使用目前的方法，特别是在超重和肥胖患者。 我们建议使用后向散射回波信号的空间相干性作为图像质量反馈 参数。时间相干性反映了电子信噪比，可以用来测量有效成像 肝脏的深度。我们新开发的图像质量度量，滞后一相干(LOC)，量化了 混响、离轴散射体、位相像差和有限信噪比的综合图像降级效应。我们的 初始模型和活体数据证明了LOC图像质量度量的健壮性 确定发射功率、谐波与基波成像、焦距的最佳患者特定设置 深度和频率。我们的初始数据也支持LOC在实时评估 各种声学窗的质量。我们建议进一步探索这些和其他成像的优化 参数，并开发脉冲序列和算法以有效地估计它们的优选设置。

A Patient-Adaptive, High MI Abdominal Scanner We propose to construct and clinically evaluate an adaptive ultrasonic scanner that quickly and automatically adjusts system controls to optimize image quality and assists the sonographer in selecting a favorable acoustic window. We hypothesize that the quality of adaptively-optimized and guided window-selection images will exceed those acquired under conventional scanning conditions. We will test these hypotheses on a modified commercial scanner under the realistic clinical condition of Hepatocellular Carcinoma (HCC) screening. Optimized images will have rapidly- and adaptively-selected transmit power, frequency, focal depth(s), imaging mode (fundamental or harmonic) and other imaging parameters and will be acquired at two Mechanical Indices (the manufacturer’s default setting (MI=1.2), and the “patient-optimized” MI up to a limit of 2.5). On a significant subset of patients, our previous work has shown significant image quality improvements and increased depths of penetration associated with increased MI levels. Our initial studies, presented in this application, show the potential clinical benefits of automated selection of MI and other imaging parameters. Automated selection of MI, as proposed, will realize the ALARA (As Low as Reasonably Achievable) principle for acoustic exposure. Currently, sonographers acquire dozens of individual images during HCC screening for physician review and documentation. A number of published studies and our experience indicate that sonographers use system controls quite sparingly, especially the transmit power level control. Automated selection of imaging parameters and guided selection of acoustic windows should not only improve image quality and depth of penetration, but should also improve the efficiency of scanning procedures and reduce sonographers’ ergonomic challenges. Our initial results and the clinical literature also demonstrate the importance of acoustic window selection in improving image quality and the physical challenges that this task presents to sonographers using current methods, especially in overweight and obese patients. We propose to use the spatial coherence of backscattered echo signals as an image quality feedback parameter. Temporal coherence reflects the electronic SNR and can be used to measure the effective imaging depth in the liver. Our newly developed image quality metric, Lag One Coherence (LOC), quantifies the combined image-degrading effects of reverberation, off-axis scatterers, phase aberration and limited SNR. Our initial phantom and in vivo data demonstrate the robustness of the LOC image quality metric in rapidly determining the optimum patient-specific settings for transmit power, harmonic vs. fundamental imaging, focal depth, and frequency. Our initial data also supports the utility of the LOC in the real-time assessment of the quality of various acoustic windows. We propose to further explore the optimization of these and other imaging parameters and to develop pulse sequences and algorithms to efficiently estimate their preferred settings.