Real-time Ultrasonic Monitoring of Tumor Ablation

描述（由申请人提供）：微创治疗对于化疗无效的肝肿瘤患者和无法手术的肝癌患者至关重要。射频（RF）和微波（MW）消融技术是间质性局灶性治疗，在这些病例中使用频率越来越高。射频或微波探头放置的图像引导以及治疗体积的初步评估对于这些手术的成功至关重要。我们和其他人已经证明，基于超声的应变和模量成像是有希望的，准确地描绘消融手术中的治疗体积。浅表结构的初步评估表明消融区域的图像对比度较高。 我们的研究将开发和评估一种新的应变成像方法，称为“电极位移弹性成像”，或EDE，以监测微创消融治疗和划定坏死区，无论治疗的深度。我们将首先测试的有效性EDE使用回波数据采集与传统的曲线 和相控阵。这将通过使用与肝脏组织等效的杨氏模量值对定制组织模拟体模进行成像来完成，以确定针对各种EDE采集参数标测消融和部分消融区域的可靠性。将对RF/微波位移引起的模型变形进行有限元分析（FEA），以更好地理解这些实验结果。然后，我们将评估人类患者的2D EDE，在典型成像深度和各种肝脏状态下采集数据，即肝细胞癌（HCC）的硬化肝脏和转移瘤的较软肝脏。EDE应变和后续X线CT图像之间的比较将提供关键信息的有效性EDE应变图像，以划定坏死区。 然后，我们将开发和测试双平面和三维（3D）体积EDE应变和模量成像使用2D矩阵相控阵换能器。将使用组织模拟体模确定不同回波数据采集条件下消融边界描绘的准确性。然后将进行体内研究，以在土拨鼠HCC模型和兔VX 2转移模型上测试双平面和3D EDE的应变和模量成像，以评价消融治疗前后癌症的描述和描绘。将使用消融组织的光学显微镜对应变和模量图像与组织病理学进行比较。最后，将使用经皮双平面和3D EDE对人类患者进行初步研究。这些研究的成功完成将为使用EDE监测微创消融治疗的临床试验铺平道路。 HCC的发病率在过去十年中翻了一番，未经治疗的死亡率为3-6个月。在降低患者发病率和降低治疗成本方面，精确的基于超声的消融治疗引导的临床意义将是很高的。

DESCRIPTION (provided by applicant): Minimally invasive treatments are essential for patients with liver tumors that do not respond to chemotherapy and for patients with inoperable liver cancers. Radiofrequency (RF) and microwave (MW) ablation techniques are interstitial, focal therapies that are being used with increasing frequency for these cases. Image guidance for placement of RF or MW probes and for initial assessments of treated volumes is essential for the success of these procedures. We and others have demonstrated that ultrasound based strain and modulus imaging are promising for accurately depicting the treated volumes in ablation procedures. Initial assessments for superficial structures demonstrate high image contrast of ablated regions. Our research will develop and evaluate a novel strain imaging method termed "electrode displacement elastography," or EDE, to monitor minimally invasive ablative treatments and delineate the zone of necrosis regardless of the depth of treatment. We will initially test the effectiveness of EDE using echo data acquired with conventional curvilinear and phased arrays. This will be done by imaging custom tissue-mimicking phantoms with Young's Modulus values equivalent to that of liver tissue to determine reliability of mapping out ablated and partially ablated regions for various EDE acquisition parameters. Finite element analysis (FEA) to model deformations induced by RF/microwave displacements will be performed to better understand these experimental results. We then will evaluate 2D EDE on human patients, acquiring data at typical imaging depths and for various liver states, i.e. cirrhotic liver for hepatocellular carcinoma (HCC) and softer livers with stiffer tumors for metastases. Comparisons between EDE strain and follow-up X-ray CT images will provide crucial information on the effectiveness of EDE strain images to delineate the zone of necrosis. We will then develop and test bi-plane and three-dimensional (3D) volumetric EDE strain and modulus imaging using a 2D matrix phased array transducer. Accuracy of ablation boundary delineation for different echo data acquisition conditions will be determined using tissue-mimicking phantoms. In-vivo studies will then be conducted to test bi-plane and 3D EDE for strain and modulus imaging both on a wood-chuck HCC model and a rabbit VX2 metastases model to evaluate depiction and delineation of cancers before and after ablation therapy. Comparisons of the strain and modulus images with histopathology using light microscopy of ablated tissue will be performed. Finally, a pilot study will be performed using percutaneous bi-plane and 3D EDE on human patients. Successful completion of these studies will pave the way for clinical trials using EDE for monitoring minimally invasive ablative therapies. Incidence of HCC has doubled in the last decade, with a mortality rate of 3-6 months without treatment. The clinical significance of accurate ultrasound-based guidance for ablation treatments will be high, both in terms of reducing patient morbidity and of lowering treatment costs.