Thoracic duct (TD) ligation has long been the treatment of choice for canine idiopathic chylothorax. Clear identification of all the TD branches at the surgical site is critical to facilitate complete ligation, and this can be difficult due to the highly variable nature of the TD system in number, location and patency of TD branches. Failure to ligate all of the TD branches may result in persistent flow of chyle into the pleural cavity through any missed ducts, and this is the single most common cause of failure with TD ligation. Performing direct positive contrast lymphography with a water soluble contrast medium, administered through a surgically implanted mesenteric lymphatic vessel catheter has been the conventional method used to identify TD branches. This procedure involves invasive surgery to both implant and remove the mesenteric lymphatic catheter, which increases patient risk and discomfort, as well as the diagnostic time and cost. Ultrasound (US) guided percutaneous administration of contrast medium into either a popliteal or mesenteric lymph node (LN) have been proposed as alternatives to mesenteric lymphatic vessel catheterisation, however their comparability with the conventional approach has not been assessed. Computed tomographic (CT) lymphography of the caudal canine TD was performed in seven beagles with contrast medium administered through a mesenteric lymphatic catheter, and by US guided percutaneous injection into a popliteal LN. Images of the TD system were collected using both helical and sequential CT modalities for each contrast medium administration technique. It was found that percutaneous popliteal lymphography had a total diagnostic procedure time just 46% of that found with mesenteric lymphatic vessel administration, and resulted in a time saving of 52 minutes. It also incurred only 29% of the total costs, and patients were assessed to have significantly less discomfort compared to mesenteric lymphatic vessel lymphography. There was no significant difference in the number of TD branches identified by the two contrast medium administration techniques (P = 0.256). However administration of contrast medium into a mesenteric lymphatic vessel did result in the largest TD branch having a significantly greater widest diameter (P < 0.001), cross-sectional area (P < 0.001) and mean Hounsfield unit (HU) value (P < 0.001) than popliteal administration. The significant difference in TD size and contrast medium concentration may help to explain the trend for popliteal administration of contrast medium to detect slightly fewer TD branches (CR = 0.830), however this study could not confirm this trend nor its possible causes. There was no significant difference in the number of TD branches identified by the two CT modalities (P = 0.417). However helical CT did result in the largest TD branch having a significantly greater widest diameter (P < 0.001), cross-sectional area (P < 0.001) and higher mean HU value (P < 0.001). It should be noted however that in this study sequential CT was consistently performed after the helical CT was completed, which could explain the differences seen between the two CT modalities in TD branch size and contrast medium concentration. Despite helical CT having the apparent advantage of a larger TD branch which contained a higher concentration of contrast medium, it was actually found that there was a trend for helical CT to detect slightly fewer TD branches (CR = 0.876). This is possibly due to the positive pressure breath hold that was used to minimise thoracic respiratory movement for the helical CT; while the sequential CT was performed during normal respiration and was therefore not subject to abnormally elevated intrapleural pressure. This study could not confirm the slight superiority of sequential CT in detecting TD branches nor the possible reasons for this apparent difference. / Dissertation (MMedVet)--University of Pretoria, 2010. / Companion Animal Clinical Studies / unrestricted

The purpose of this literature review is to investigate the most effective forms of self-care that patients can perform to reduce swelling caused by lymphedema. Lymphedema may occur secondary to lymph node trauma, which makes it difficult for lymph fluid to leave an extremity. Even though lymphedema is more recognized as a side effect of breast cancer treatment, it can also be the result of many other ailments or treatments and can be present in any part of the body. By knowing which therapies are most effective, nurses and other health care professionals can educate patients to help ease the burden caused by this debilitating condition. This thesis discusses the results of clinical trials that studied different methods of self-care including exercises, bandaging, compression garments, sequential compression devices, and performing manual lymphatic drainage. The conclusion derived from the review of multiple studies is that participating in a combination of multiple therapies is the most effective means of lymphedema management and should be considered the ideal standard of care.

Background: Before making any treatment decisions for patients with non-small cell lung cancer (NSCLC), it is crucial to determine whether the cancer has spread to the mediastinal lymph nodes (LNs). The preferred method for mediastinal staging is Endobronchial Ultrasound Transbronchial Needle Aspiration (EBUS-TBNA). However, EBUS-TBNA has been reported to generate inconclusive results as much as 40% of the time. Since this jeopardizes good patient care, there is near-universal consensus on the need to develop and study a novel method for LN staging. Recent research has shown that AI and deep learning are used to accurately interpret images with comparisons to clinicians in radiology, pathology, and cardiology. Additionally, EBUS-Elastography is a novel modality which could be used as an adjunct to EBUS-TBNA for LN staging. This technology uses impedance ultrasonography to measure tissue stiffness. Methods: There are three parts to this thesis. The first part involved the training, validating, and testing NeuralSeg, a deep neural network, to predict LN malignancy based on B-mode EBUS-TBNA images. The second part of this thesis involves EBUS-Elastography, defining the blue colour threshold and the optimal SAR cut-off value based on the blue threshold that most accurately distinguished benign and malignant LN. Finally, this thesis's third part involves validating part II's findings. Results: Part I resulted in an overall accuracy of 80.63% (76.93% to 83.97%), a sensitivity of 43.23% (35.30% to 51.41%), a specificity of 96.91% (94.54% to 98.45%), a positive predictive value of 85.90% (76.81% to 91.80%), a negative predictive value of 79.68% (77.34% to 81.83%), and an AUC of 0.701 (0.646 to 0.755). Part II Level 60 was chosen as the blue threshold with an AUC of 0.89 (95% CI: 0.77-1.00), and the optimal SAR cut off was found to be 0.4959 with a sensitivity of 92.30% (95% CI: 62.10% to 99.60%) and a specificity of 76.50% (95% CI: 49.80% to 92.20%). Using the blue threshold and SAR cut-off, the results of part III resulted in an overall accuracy of 70.59% (95% (CI) 63.50% to 77.01%), the sensitivity of 43.04% (CI: 31.94% to 54.67%), and a specificity of 90.74% (CI: 83.63% to 95.47%). Conclusion: It was observed that both AI and AI-powered EBUS-Elastography achieved high specificities on larger sample sizes, indicative that these methods may be helpful in identifying LN malignancy. However, due to the novelty of these technologies, more extensive multi-centre studies must be conducted before these processes can be standardized. / Thesis / Master of Health Sciences (MSc) / Non-Small Cell Lung Cancer (NSCLC) treatment decisions are made using vital information by performing biopsies to collect tissue from the lymph nodes near the lungs. The current method is called Endobronchial Ultrasound Transbronchial Needle Aspiration (EBUS-TBNA), which involves a scope with a fine needle attached to it. This scope is led down the airway and guided by ultrasound to obtain the tissue needed to determine whether the lymph nodes have cancerous tissue. If the lymph nodes contain cancerous tissue, the patient may need chemotherapy; however, lung surgery may be the best treatment option if they do not. Many factors impact how successfully these tissue samples can be obtained, such as the skill and experience of the surgeon. These factors often lead to inconclusive results, making it difficult to make correct treatment decisions. Novel technologies such as Artificial Intelligence and Elastography are being used to diagnose lung cancer by interpreting images and providing information on tissue stiffness. We trained an Artificial Intelligence program to predict malignancy based on EBUS-TBNA images. Additionally, we trained the AI program to analyze Elastography images to aid us in understanding the relationship between the colour pattern of the elastography images and cancerous tissue. This thesis assesses how these novel technologies contribute to lung cancer diagnosis.

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Background: At the time of endobronchial ultrasound (EBUS) staging, ultrasonographic features can be used to predict mediastinal lymph node (LN) malignancy. Predictive tools have been developed, however they have not gained widespread use due to lack of research demonstrating validity and reliability. We sought to develop a novel predictive tool, the Canada Score, capable of predicting malignancy and potentially guide LN biopsy decision making. Methods: We prospectively analyzed the ultrasonographic features of LNs from patients with NSCLC. Ultrasonographic features were identified by a single experienced endoscopist, this data was used to develop the Canada Score. Pathological specimens were used as the gold standard for determination of malignancy. Videos were then circulated to endoscopists across Canada, who were also asked to identify ultrasonographic features for each LN. Hosmer- Lemeshow test, logistic regression, receiver operator characteristic (ROC) curve, and Gwet’s AC1 analyses were used to test the performance, discriminatory capacity, and inter-rater reliability of the Canada Score. Results: A total of 300 LNs from 140 patients were analyzed by 12 endoscopists across 7 Canadian centres. Backwards elimination was used to create a multivariate model. Hosmer-Lemeshow test and ROC curves indicated the model was well-calibrated (chi2=11.86, p=0.1567) with good discriminatory power (c- statistic= 0.72 ±0.042, 95%CI: 0.64-0.80). Beta-coefficients were used to create a simplified score out of four. Evaluation of the tool showed that LNs scoring 3 or 4 had odds ratios of 15.17 (p<0.0001) and 50.56 (p=0.001), respectively for predicting malignancy. A score of 4/4 was associated with 99.59% specificity and a positive likelihood ratio of 22.78. Inter-rater reliability for a score ≥ 3 was 0.81 ± 0.02 (95%CI: 0.77-0.85). Conclusions: The Canada Score shows excellent performance in identifying malignant LN at the time of EBUS. A cut-off of ≥ 3 has the potential to inform decision-making regarding biopsy or repeat/mediastinoscopy if the initial results are inconclusive. / Thesis / Master of Science (MSc) / During lymph node staging for lung and esophageal cancer, specific features of lymph nodes can be seen. Using diagnostic tools these features can be used to predict whether a lymph node is cancerous or benign. However, many of these diagnostic tools are inaccurate or unreliable. To address this, this thesis aimed to develop a novel diagnostic tool based on lymph node features seen during staging procedures and determine its clinical usefulness and application to the wider lung and esophageal cancer population. This thesis also aimed to use improved methods to develop this diagnostic tool such that patient and clinician experiences would be significantly improved. The results of this thesis may contribute to a reduction in the number of repeat procedures required for patients undergoing staging prior to their treatment for lung and esophageal cancers.

2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin is well known for its immunotoxic effects on the thymus, as well as on B and T lymphocyte functions. Previous studies suggested that TCDD exerted immunotoxic effects only on cells differentiating in response to antigenic challenge. To this date, no work has been done to characterize the long-term effects of TCDD on the activated cells. Additionally, no studies have been done to determine whether TCDD has any effect on resting T cells. In the current study, therefore, we investigated the effects of TCDD on activated and resting cells within the same animal. T cells in the popliteal lymph node cells were activated by rear footpad immunizations with anti-CD3 antibodies. Distally-located axillary lymph nodes were chosen as a source of naive and resting T cells. Our results demonstrate that TCDD acted at the time of cell differentiation to suppress the immune responses of activated T cells, but failed to suppress, and at times, enhanced the immune responses of resting T cells. The TCDD-induced immunomodulations were temporary; responsiveness of both activated and resting T cells from TCDD-treated animals returned to normal by two weeks post-treatment, suggesting that TCDD does not affect memory cells. Futhermore, we provide direct evidence that the TCDD-induced immunosuppression in activated cells is due to increased apoptosis of CD3+ T cells. TCDD also induced significant changes in cell surface markers expressed by naive and activated T cells. Together our data suggested that TCDD suppresses the proliferative responsiveness of only the activated, but not naive, T cells and that this is accomplished by induction of increased apoptosis of activated T cells. These studies shed new light on the mechanism through which TCDD induces increased susceptibility to infections and cancer in the vertebrate host. / Master of Science

In dogs with large primary tumors, regional lymph node involvement or evidence of distant metastasis can have worse prognoses and significantly decreased survival. Lymph node size alone has been shown to be insufficient as a predictor for the accurate clinical staging of some canine neoplasia, including oral malignant melanoma. However, regional lymph nodes of the oral cavity, such as the medial retropharyngeal lymph nodes, are difficult to access for routine sampling. Diffusion weighted magnetic resonance imaging (DWI) has demonstrated the ability to differentiate metastatic from inflammatory/benign lymph nodes in clinical studies with human cancer patients through the calculation of quantitative values of diffusion termed apparent diffusion coefficients (ADC). The objective of this exploratory study was to evaluate DWI and ADC as potential future methods for detecting malignant lymph nodes in dogs with naturally occurring disease. We hypothesized that DWI would identify significantly different ADC values between benign and metastatic lymph nodes in a group of canine patients with head or neck disease. Our results demonstrated that two of four observers identified a significant difference between the mean ADC values of the benign and metastatic lymph nodes. When data from all four observers were pooled, the difference between the mean ADC values of the benign and metastatic lymph nodes approached but did not reach significance (P-value: 0.0566). Therefore, our hypothesis was not supported. However, DWI does show promise in its ability to differentiate benign from metastatic lymph nodes, and further studies with increased patient numbers are warranted / Master of Science

Made available in DSpace on 2016-03-22T17:26:57Z (GMT). No. of bitstreams: 1 Neivo.pdf: 343535 bytes, checksum: e65c41380c8ceabe9bc780ffcc1c99f1 (MD5) Previous issue date: 2005-02-14 / Objective: The objective of this study is to describe the reproducibility of the sentinel lymph node technique in patients with prostate cancer and verify if there is improved accuracy over modified lymphadenectomy. Material and methods: Twenty-three patients with biopsy proven prostate cancer were enrolled in this study. Lymphoscintigraphy was performed after the transrectal administration of 99mTc-Sulphur Colloid guided by ultrasound, with one injection in each prostate lobe. Images were obtained 15 and 180 minutes after injection. Sentinel lymph node was harvested during surgery using a gamma probe, followed by extended lymphadenectomy. Results: The mean age of the patients in this study was 66 years old. An average of 3.36 sentinel lymph nodes was found for each patient. Radioactive lymph nodes were identified by the gamma probe in 21 out of 23 patients. In one of the patients there was no radiopharmaceutical migration from the injection site and in another the sentinel lymph node was visualized by lymphoscintigraphy but was not found during surgery. Three patients had lymph node metastasis; in one of these patients the sentinel lymph node was the only positive node and was found outside the modified lymphadenectomy region (dissection of the lymph nodes from the obturator fossa and the external iliac). Conclusion: Sentinel lymph node biopsy in prostate cancer adds important information to the staging of patients, not always attained through the lymphadenectomy restricted to the obturator fossa and external iliac. Such information is essencial for the choice of the best treatment to be applied. / n