Real-time Ultrasonic Monitoring of Tumor Ablation

描述(申请人提供)：对于化疗无效的肝肿瘤患者和不能手术的肝癌患者，微创治疗是必不可少的。射频(RF)和微波(MW)消融技术是间质内的局部治疗方法，在这些病例中使用的频率越来越高。对于射频或微波探头的放置和治疗体积的初步评估的图像指导对于这些程序的成功至关重要。我们和其他人已经证明，基于超声的应变和模数成像在准确描述消融过程中的治疗体积方面很有希望。对表面结构的初步评估显示消融区域的高图像对比度。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，用于监测微创消融治疗并描绘坏死区，而不考虑治疗的深度。我们将使用常规曲线采集的回波数据初步测试EDE的有效性 和相控阵。这将通过成像具有与肝组织相等的杨氏模量值的定制组织模拟体模来完成，以确定为各种EDE采集参数绘制消融和部分消融区域的可靠性。为了更好地理解这些实验结果，将进行有限元分析(FEA)来模拟射频/微波位移引起的变形。然后，我们将在人类患者身上评估2D EDE，收集典型成像深度和各种肝脏状态的数据，例如肝细胞癌(HCC)的肝硬变和肿瘤较硬的转移性较软的肝脏。EDE应变图像与后续X光CT图像的比较将为EDE应变图像描绘坏死区的有效性提供关键信息。然后，我们将使用2D矩阵相控阵换能器开发和测试双平面和三维(3D)体积EDE应变和模数成像。不同回波数据采集条件下消融边界描绘的准确性将使用模拟组织的模体来确定。然后，将进行体内研究，在木卡盘肝癌模型和兔VX2转移模型上测试双平面和3DEDE的应变和模数成像，以评估消融治疗前后肿瘤的描绘和描绘。使用光学显微镜对消融组织的应变和模数图像与组织病理学进行比较。最后，将在人类患者身上进行一项先导性研究，使用经皮双平面和3D EDE。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。在过去的十年中，肝癌的发病率翻了一番，未经治疗的死亡率为3-6个月。准确的超声引导消融治疗的临床意义将是很高的，无论是在减少患者发病率和降低治疗成本方面。

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.