Smith, NicolasDunbar, RodReynolds, Hayley Maria2010-05-112010-05-112008http://hdl.handle.net/2292/5792This thesis aimed to improve visualisation and analysis of potential patterns of melanoma spread from the skin to lymph nodes. For this purpose, anatomically based geometric models of the skin and lymph nodes have been created. A three-dimensional (3D) finite element (FE) skin model has been constructed using the Visible Human (VH) male dataset and a Sawbones head and neck model. A discrete lymph node model was also created using the VH dataset. This study has been conducted in collaboration with the SydneyMelanoma Unit (SMU), in Sydney, Australia. Clinicians at the SMU have recorded an extensive lymphoscintigraphy (LS) database, accurately mapping skin lymphatic drainage from over 5000 patients with cutaneous melanoma. The SMU’s entire LS database was mapped from two-dimensional LS images onto the 3D anatomical model. Melanoma sites were mapped onto the skin model using free-form deformation and projection techniques, while draining node fields were mapped onto a reduced lymph node model. Spatial heat maps were created using field fitting to visualise the likelihood that any area of skin would drain to a particular node field, or a specified number of node fields. An interactive skin selection tool was also developed to provide dynamic predictions of the draining node fields from any region of skin. The heat maps and interactive skin selection tool quantified that lymphatic drainage of the torso was highly complex, where the most unpredictable regions were located near Sappey’s lines. Drainage from skin on the upper and lower limbs was the most predictable, almost always draining to ipsilateral axillary and groin node fields respectively. Skin on the head and neck were shown to usually drain to two or more node fields, where the most common node fields were the cervical level II and preauricular node fields. Detailed statistical analysis was then conducted to investigate widely accepted assumptions about lymphatic drainage. Sappey’s lines were shown to be highly inaccurate at predicting lymphatic drainage from the skin of the torso. At least 12.5% of all melanoma sites located on the torso showed drainage across Sappey’s lines, and nearly the entire torso demonstrated ambiguous lymphatic drainage. A multinomial statistical model was fitted to the LS data to investigate whether lymphatic drainage was symmetric about the body’s vertical midline. Results showed that a significant proportion of the skin was likely to have symmetric lymphatic drainage patterns. Asymmetry that was shown within specific regions was likely due to an asymmetric distribution of melanoma sites within that region and/or a sparsity of data. Regions that indicated symmetry were reflected, providing a larger LS dataset to improve the statistical accuracy of drainage predictions. A cluster analysis was conducted using this reflected LS dataset to group regions of skin that drained in a similar manner. Results indicated that the dominant axillary, groin, cervical level II and preauricular node fields drained significant areas of skin. Clustering resulted in division of the torso into regions similar to Sappey’s lines, although an additional cluster formed in the middle of the anterior and posterior torso where predominantly ambiguous lymphatic drainage occurred. Confidence intervals were calculated using non-parametric bootstrapping to further determine the statistical accuracy of drainage predictions from each of these clusters. This body of research has been presented as four papers, which have either been published or will be submitted to international peer-reviewed journals: 1. Reynolds, H. M., Dunbar, P. R., Uren, R. F., Thompson, J. F. & Smith, N. P. (2007), ‘Mapping melanoma lymphoscintigraphy data onto a 3D anatomically based model’, Annals of Biomedical Engineering, 35:(8),1444-1457. 2. Reynolds, H. M., Dunbar, P. R., Uren, R. F., Blackett, S. A., Thompson, J. F. & Smith, N. P. (2007), ‘Three-dimensional visualisation of lymphatic drainage patterns in patients with cutaneous melanoma’, The Lancet Oncology, 8:(9),806-12. 3. Reynolds, H. M., Smith, N. P., Uren, R. F., Thompson, J. F., & Dunbar, P. R. (2008), ‘Threedimensional visualization of skin lymphatic drainage patterns from the head and neck’, Head & Neck, accepted. 4. Reynolds, H. M., Walker, C. G., Dunbar, P. R., O’Sullivan M. J., Uren, R. F., Thompson, J. F. & Smith, N. P. (2008), ‘Redefining the understanding of skin lymphatic drainage through statistical analysis’, submitted. This work has also been presented at the following three international conferences: 1. 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, New York, USA. Aug 30-Sep 3, 2006. 2. Biomedical Engineering Society 2007 Annual Fall Meeting, Los Angeles, California. Sep 26-29, 2007. 3. 6th International Sentinel Node Society Meeting. Sydney, Australia. Feb 18-20, 2008.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmhttp://creativecommons.org/licenses/by-nc-sa/3.0/nz/Thesis2010-05-11Copyright: The authorQ112878119