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calculated after conventional diagnostic ultrasound exam was performed by a fellowship-trained musculoskeletal radiologist. Statistical analysis was performed comparing normal versus abnormal tendons, and comparing partial tear versus tendinopathy, using the final diagnosis from the conventional diagnostic ultrasound as the standard. Results: Statistical analysis comparing normal and abnormal tendons showed that AE achieved 90% sensitivity, 100% specificity, and 93% accuracy. Statistical analysis comparing partial tear versus chronic tendinopathy within the abnormal tendons showed that AE achieved 80% sensitivity, 100% specificity and 90% accuracy. Conclusion: Acoustoelastography is a new tissue characterization method that has promising clinical potential for diagnostic musculoskeletal ultrasound. 0531 Central Hypoechogenic Line on the Ultrasonographic Image of the Meniscus: Does It Represent a Meniscal Tear? Sang Y Lee, Chonbuk National University Hospital, Department of Radiology, Korea Chun A Lee, Chonbuk National University Hospital, Department of Radiology, China Joo H Lee, Chonbuk National University Hospital, Department of Orthopedics, Korea Young J Yim, Chonbuk National University Hospital, Department of Orthopedics, Korea Chong S Kim, Chonbuk National University Hospital, Department of Radiology, Korea Objective: A central hypoechogenic line, which is perpendicular to the meniscocapsular junction, is a common ultrasonographic finding of the meniscus. The purpose of this study was to determine the histological basis of the central hypoechogenic line of the meniscus. Methods: A total of 13 menisci were collected from 10 patients who underwent total knee replacement. All menisci appeared grossly normal were selected. Ultrasonographic images of each meniscus were obtained using 17MHz probe on coronal plane of the knee joint. Multiple histological slides were made from the imaged portion of each meniscus. Region-by-region correlation between the ultrasonographic images and histological slides was performed. Results: Ten out of 13 menisci showed central hypoechogenic lines on ultrasonographic images. Those lines extended from the peripheral to central portion. The number of lines on US image was one (n ⫽ 8), two (n ⫽ 1) or three (n ⫽ 1). The line in the peripheral portion was more clearly demarcated than that in the central portion on US images. On histological slides hypoechogenic lines corresponded central core structure, which was normal dense fibrous tissue. Four menisci showed no line on ultrasonographic images. Histological examination of those menisci showed diffuse mucinous or fibrinous degeneration in both peripheral and central portions of menisci. Conclusions: Central hypoechogenic line detected on ultrasonographic images of menisci could be a normal dense fibrous structure of the meniscus. The interpretation of central hypoechogenic line as the true meniscal tear should be made with caution. 0532 Sonoelastographic Evaluation of Achilles Tendon in Amateur Symptomatic Runners Luca M Sconfienza, IRCCS Policlinico San Donato, San Donato Milanese, Italy Enzo Silvestri, Ospedale Evangelico Internazionale, Genova, Italy Stefano Longo, Laboratory of Sport Analysis, University of Milano, Italy Marco A Cimmino, Department of Internal Medicine, University of Genova, Italy
Volume 35, Number 8S, 2009 Purpose: Sonoelastography is a recently developed ultrasound (US) technique that allows in vivo assessment of tissue mechanical properties. Up to now, this technique has been mainly used to investigate prostatic tumours and breast masses. The aim of our paper is to use sonoelastography to evaluate Achilles tendon in amateurs symptomatic runners. Materials and Methods: Sixteen patients referred for unilateral Achilles tendon pain due to overuse associated with amateur sporting activities and 24 healthy controls were studied. US and sonoelastography were performed on 16 symptomatic tendons and 48 control tendons with a system equipped with a 10-6 MHz broadband linear array. The array was positioned at the calcaneal enthesis, retrocalcaneal bursa and in 3 different areas of the tendon body. The elastogram colour range was translated in a numeric score. Results were compared by the Kruskall Wallis test. Results: At grey scale US, symptomatic tendons showed a variety of basic changes in fibrillar pattern (2): increased tendon thickness (12), interruption (5), fragmentation (5), and disappearance of fibrillar echotexture (5). In the control group, we observed 1 case of increased tendon thickness and 5 cases of disappearance of fibrillar echotexture. By sonoelastography, no difference was observed between symptomatic and control tendons at the enthesis and bursa. Symptomatic tendons bodies were significantly harder than control ones, showing a prevalence of blue to green colour (p⬍0.0001). Conclusion: Sonoelastography shows increased stiffness in symptomatic enlarged Achilles tendons in comparison to normal ones. Long-term studies are needed to evaluate if these findings have a prognostic value. 0533 Breast Cancer Staging with Sonography Gary Whitman, Unviversity of Texas MD Anderson Cancer Ctr, United States This presentation will discuss the use of sonography for staging in breast cancer. This presentation will focus on staging the breasts and the regional (axillary, infraclavicular, supraclavicular, and internal mammary) lymph nodes. Staging intramammary lymph nodes will also be covered. Ultrasound has been shown to be useful in demonstrating bilateral, multicentric, and multifocal disease in the breasts that was not identified on mammography and/or clinical examination. Likewise, sonography has been shown to be helpful in demonstrating metastatic lymph nodes that were not identified on mammography and/or clinical examination. In addition to identifying additional foci of disease in the breasts and the regional lymph nodes, sonography plays a major role in guiding biopsies in order to document disseminated disease. Ultrasound-guided fine needle aspiration and core needle biopsy have been shown to be efficacious in sampling breast lesions and regional lymph nodes. A successful ultrasound-guided fine needle aspiration program is dependent on appropriate cytology support. If strong cytology support is not available, then core needle biopsy should be performed. In addition to guiding breast biopsies and biopsies of the regional lymph nodes, sonography plays an important role in guiding placement of marker clips (usually in breast lesions and rarely in lymph nodes). Accurate staging is important as appropriate staging leads to appropriate treatment and treatment sequencing with chemotherapy, radiation therapy, and surgery. 0534 Ultrasound Guided Biopsy of the Breast Woo Kyung Moon, Seoul National University Hospital, Korea The use of ultrasound (US) in breast interventional procedures has several advantages over stereotactic guidance. It is a lack of ionizing radiation, real-time visualization of the needle, use of non-dedicated
Abstracts equipment, a shorter procedure time, low in cost, and improved patient comfort. For US-guided needle biopsy, the lesion must be sonographically evident. It is difficult to detect and biopsy small clusters of calcifications and small solid masses particularly in large, fatty breasts. Tissue-acquisition devices for percutaneous biopsy include fine needles, spring-loaded guns and automated needles, and directional vacuum-assisted biopsy devices. The decision as to which biopsy instrument to use depends on various factors including accuracy, complication rates, time required for the biopsy, and cost. In SNUH, we use 14 g gun for the biopsy of palpable masses and well-defined solid masses regardless of size. This constitutes about 95% of our biopsy cases. Vacuum-assisted biopsy devices are preferred at our institution, however, when the acquisition of greater amounts of material is encouraged by more subtle sonographic findings, such as, small ill-defined nodules less than 1.5 cm, intraductal or intracystic masses, and microcalcifications with or without associated masses. Digital mammography-guided skin marking and 11-gauge vacuum-assisted device can improve the visualization and targeting of suspicious calcifications for US-guided biopsy. To reduce false negative diagnoses, an immediate repeat biopsy should be recommended if there is any imaging-histologic discordance, or if targeting is in question in addition to the presence of atypical lesions on core specimen. 0535 Sentinel Lymph Node Mapping Gary Whitman, Unviversity of Texas MD Anderson Cancer Ctr, United States In this presentation, sentinel lymph node mapping in breast cancer will be discussed, with an emphasis on sonographic techniques. In addition, nuclear medicine techniques and mammographic techniques will be presented. The sentinel lymph node concept is based on the notion that the sentinel lymph node, the first draining lymph node in a nodal basin, is reflective of that entire nodal basin. For example, a negative sentinel lymph node would indicate that the lymph node basin was negative, and a positive sentinel lymph node would indicate that there was evidence of metastatic disease in that lymph node basin. Sentinel lymph node mapping has resulted in fewer complications (such as lymphedema, nerve damage, and hematoma formation) when compared to axillary lymph node dissection. In addition, sentinel lymph node mapping has facilitated careful histopathologic inspection of a few lymph nodes with thin sectons, compared to axillary lymph node dissection, with more lymph nodes sampled, but with thicker sections. Mammography and ultrasound play important roles in guiding peritumoral radiopharmaceutical injections. While mammographicallyguided injections are often performed with more than one needle, nearly all ultrasound-guided injections are performed with one needle insertion. Currently, the sentinel lymph node is identified by visual inspection after blue dye injection and/or by demonstration of radiopharmaceutical uptake with a hand-held counter after the injection of technetium 99m sulfur colloid. In the future, ultrasound contrast agents may facilitate sonographic visualization of sentinel lymph nodes. 0536 Gray-Scale Contrast-Enhanced Utrasound in Detecting the Sentinel Lymph Nodes: An Animal Study Yuexiang Wang, Chinese PLA General Hospital, China Jie Tang, Chinese PLA General Hospital, China Junlai Li, Chinese PLA General Hospital, China Zhigang Cheng, Chinese PLA General Hospital, China
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Objective: To investigate the usefulness of gray-scale contrast-enhanced ultrasound in detecting the sentinel lymph nodes. Methods: Contrast-enhanced ultrasound was performed in five normal dogs (four female, 1 male) after subcutaneous administration of Sonovue (a sonographic contrast agent). Four regions in each animal were examined respectively. After the contrast-enhanced ultrasound, 0.8ml of blue dye was injected into the same location as Sonovue and the sentinel lymph nodes were detected by surgical dissection. The findings of contrast-enhanced ultrasound were compared with those of blue dye. Results: Twenty-one sentinel lymph nodes were detected by contrastenhanced ultrasound while 23 were identified by blue dye with surgical dissection. Compared with the blue dye, the detection rate of contrastenhanced ultrasound for the sentinel lymph nodes is 91.3% (21/23). Two patterns of enhancement in the sentinel lymph nodes were observed: complete enhancement (5 sentinel lymph nodes) and partial enhancement (16 sentinel lymph nodes). The lymphatic channels were demonstrated as hyperechogenic linear structures leading from the injection site and could be readily followed to their sentinel lymph nodes. Histopathologic examination showed proliferation of lymphatic follicles or lymphatic sinus in partial enhanced sentinel lymph nodes while normal lymphatic tissue was demonstrated in completely enhanced sentinel lymph nodes. Conclusions: Sonovue combined with gray-scale contrast-enhanced ultrasound may provide a feasible method for detecting the sentinel lymph nodes. 0537 Analysis of False-Negative Results After US-Guided 14-Gauge Core Needle Breast Biopsy Eun-Kyung Kim, Department of Diagnostic Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Korea Ji Hyun Youk, Korea Eun Ju Son, Korea Min Jung Kim, Korea Jin Young Kwak, Department of Diagnostic Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Korea Purpose: The purpose of this retrospective study was to determine the false-negative rate and to evaluate the clinical, radiologic, or histologic features of false-negative results at ultrasound -guided 14-gauge core needle biopsy (CNB). Methods: A total of 3724 masses from 3308 women who had undergone ultrasound -guided 14-gauge CNB and had at least a 2-year post-biopsy follow-up were included. The histology of CNB was reviewed and correlated with the excisional biopsy or long-term imaging follow-up. For the missed cancer, the time interval between CNB and excision, the reasons for rebiopsy, and the procedural or lesion characteristics were analyzed. Results: Of 1706 benign CNBs, 50 additional malignancies were found at excision (false-negative rate, 2.5% of 1982 with a final diagnosis of malignancy). 41 of 50 false negatives were found immediately of which 28 had rebiopsy because of imaging-histologic discordance. Regarding the frequency of malignancy by the reasons for rebiopsy, suspicious imaging findings (24%, 37 of 152; discordance in 34, progression at imaging follow-up in three) showed significantly higher frequency than suspicious clinical findings or request (1%, 13 of 977). Regarding the experience of radiologists, the number of core, palpable abnormality, and lesion size, no significant differences in false-negative rate were found. Conclusions: Most false negatives were found immediately and imaging-histologic discordance was the most important clue. Careful cor-