Acoustic Radiation Force Imaging of Colorectal Tissues

描述（由申请人提供）： 我们开发了一种基于短持续时间（<1 ms）、声辐射力的局部应用和使用超声方法对组织的响应进行成像的新方法。该技术的初步结果表明，它能够成像的食管，胃和直肠离体的粘膜和肌肉层的机械性能，以及在体内淋巴结提供临床相关的建筑信息。我们已经标记这种方法的声辐射力脉冲（ARFI）成像，并已开发出一种实时ARFI成像系统，利用Beowulf集群结合修改后的商业超声扫描仪和换能器的经皮成像。我们提出了体外和体内研究，以评估ARFI成像的能力，以确定肠壁浸润程度的结直肠癌（T-阶段），并评估相关的局部淋巴结（N-阶段）的恶性参与术前分期的目的，以指导治疗决策。穿透固有肌层进入直肠周围组织的直肠癌（uT 3-uT 4）和表现出局部淋巴结受累的直肠癌（N+）通常用新辅助化疗和放疗治疗，以便在根治性切除之前减小肿瘤大小。包含在直肠层（粘膜、粘膜下层和固有肌层，uT 0-uT 2）内而不涉及淋巴结（N-）的肿瘤通常仅需要局部经肛门切除，并且不需要新辅助治疗。后一种方法比前一种方法耐受性更好，并发症更少，费用也更低。目前用于结直肠癌术前分期的方法报道T分期的准确性仅为69-90%，N分期的准确性低于65%。过度分期最常发生在uT 2和uT 3之间的关键区别处。ARFI图像根据组织的力学特性和几何结构来区分组织，这正是T分期所需的信息。我们提出有限元建模研究和幻影试验，以指导信号采集和处理方法，探索分辨率和对比度的基本问题，并优化分层器官的ARFI成像性能。我们建议评估结直肠组织对ARFI激发的反应与其组织学之间的关系，包括评估与恶性肿瘤相关的结缔组织增生和细胞性增加，并将ARFI位移图像与机械压头试验相关联。我们建议评估ARFI成像在离体组织样本中对结直肠肿瘤和淋巴结进行分期的能力，并将其与传统超声和组织学作为金标准进行比较。最后，我们提出了一个试点临床研究比较ARFI和超声分期结直肠癌在体内。

DESCRIPTION (provided by applicant): We have developed a new method of imaging the mechanical properties of tissues based on short duration (<1 ms), localized applications of acoustic radiation force and imaging the tissues' response using ultrasonic methods. Initial results with this technique demonstrate its ability to image mechanical properties of the mucosal and muscular layers of the esophagus, stomach, and rectum ex vivo, as well as providing clinically relevant architectural information in lymph nodes in vivo. We have labeled this method Acoustic Radiation Force Impulse (ARFI) imaging, and have developed a real-time ARFI imaging system utilizing a Beowulf cluster combined with modified commercial ultrasonic scanners and transducers for transcutaneous imaging. We propose both ex vivo and in vivo studies to evaluate the ability of ARFI imaging to determine the degree of bowel wall invasion of colorectal cancers (T-stage) and to evaluate the malignant involvement of the associated local lymph nodes (N-stage) for the purpose of preoperative staging in order to guide treatment decisions. Rectal cancers that have penetrated through the muscularis propria into the peri-rectal tissue (uT3-uT4) and those exhibiting local lymph node involvement (N+) are generally treated with neoadjuvant chemotherapy and radiation in order to reduce tumor size prior to radical resection. Tumors contained within the rectal layers (mucosa, submucosa and muscularis propria, uTO-uT2) without nodal involvement (N-) generally require only local transanal excision, and no neoadjuvant treatment. The latter approach is better tolerated, with fewer complications and appreciably less cost than the former. Current methods for preoperative staging of colorectal cancers report accuracies of only 69-90% for T-staging, and less than 65% for N-staging. Overstaging occurs most often at the critical distinction between uT2 and uT3. ARFI images distinguish tissues based upon their mechanical properties and geometric structure, which is exactly the information required for T-staging. We propose finite element modeling studies and phantom trials to guide signal acquisition and processing methods, to explore the fundamental issues of resolution and contrast, and to optimize the performance of ARFI imaging of layered organs. We propose to evaluate the relationship between colorectal tissues' response to ARFI excitation and their histology, including the assessment of desmoplasia and increased cellularity which are associated with malignancy, and to correlate ARFI displacement images with mechanical indenter tests. We propose to evaluate the ability of ARFI imaging to stage colorectal tumors and nodes in ex vivo tissue samples, comparing it with conventional ultrasound and histology as the gold standard. Finally, we propose a pilot clinical study comparing ARFI and ultrasonic staging of colorectal cancers in vivo.