Acoustic Radiation Force Imaging of Colorectal Tissues

描述(由申请人提供)： 我们发展了一种新的成像方法，基于短时间(&lt；1ms)、声辐射力的局部施加和使用超声方法成像组织的响应。这项技术的初步结果表明，它能够在体外成像食道、胃和直肠的粘膜和肌层的机械特性，并在体内提供临床上相关的淋巴结结构信息。我们将这种方法标记为声辐射力脉冲(ARFI)成像，并开发了一种实时ARFI成像系统，该系统利用Beowulf集群结合改进的商用超声扫描仪和换能器进行经皮成像。我们建议进行体外和体内研究，以评估ARFI成像确定结直肠癌肠壁侵犯程度(T期)的能力，并评估相关局部淋巴结(N期)的恶性受累程度，以达到术前分期的目的，以指导治疗决策。已穿过固有肌层进入直肠周围组织的直肠癌(UT3-UT4)和局部淋巴结受累(N+)的直肠癌通常在根治性切除前进行新辅助化疗和放射治疗，以缩小肿瘤大小。肿瘤位于直肠层(粘膜、粘膜下层和固有肌层，UTO-UT2)，无结节侵犯(N-)，一般只需要局部经肛门切除，不需要新的辅助治疗。后一种方法的耐受性更好，并发症更少，成本也明显低于前者。目前结直肠癌手术前分期的方法报告T分期的准确率只有69-90%，而N分期的准确率不到65%。过度估计最常发生在uT2和uT3之间的关键区别处。ARFI图像根据组织的机械特性和几何结构区分组织，这正是T分期所需的信息。我们提出了有限元建模研究和体模试验，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，并优化层状器官的ARFI成像性能。我们建议评估大肠组织对ARFI刺激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增多，并将ARFI移位图像与机械压痕试验相关联。我们建议评估ARFI成像在体外组织样本中分期结直肠肿瘤和结节的能力，并将其与常规超声和组织学进行比较，作为金标准。最后，我们提出了一项试验性临床研究，比较了ARFI和超声在体内对结直肠癌的分期。

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.