Weaver Wfu 0248D 10499.Pdf
Total Page:16
File Type:pdf, Size:1020Kb
MORPHOLOGICAL ANALYSIS OF CHANGES IN THE THORACIC SKELETON WITH AGE AND GENDER BY ASHLEY ANNE WEAVER A Dissertation Submitted to the Graduate Faculty of VIRGINIA TECH – WAKE FOREST UNIVERSITY SCHOOL OF BIOMEDICAL ENGINEERING & SCIENCES In Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Biomedical Engineering December 2013 Winston-Salem, North Carolina Approved by: Joel D. Stitzel, PhD, Advisor, Chair Stefan M. Duma, PhD Warren N. Hardy, PhD Leon Lenchik, MD R. Shayn Martin, MD Dedication I dedicate this dissertation work to the millions of people injured in motor vehicle crashes each year. Especially, I dedicate this to my friend, Brooke, who lost her eyesight from a motor vehicle crash in September. May the personal tragedies of those injured in crashes empower researchers, engineers, and policy makers to enhance automotive safety in the future. ii Acknowledgements To my advisor, Dr. Joel Stitzel, I thank you for the opportunity to conduct research with the Center for Injury Biomechanics (CIB). Your guidance on this project as well as other projects I’ve worked on has been invaluable. I appreciate the many opportunities you’ve afforded me during graduate school to grow academically and professionally. Thank you for being so accommodating and willing to help when I’ve needed it the most. To the remainder of my committee, thank you for your time spent reviewing this dissertation research. Thanks to the many people of the CIB that have assisted me with either this project or other research. Special thanks to Sam Schoell, Calli Nguyen, and Sarah Lynch who substantially contributed to this project. I could always depend on each of you and am truly grateful for all your hard work. Thanks also to Dr. Joseph Maldjian, Ben Wagner, and Lizz Davenport of the ANSIR lab for their contribution to the image processing aspects of this project. I thank the following people also that contributed to various portions of this research: Dr. Leon Lenchik, Dr. Chris Wyatt, AJ Allen, Elizabeth Armstrong, Nathan Croswell, John Keller, Hannah Kim, Lauren Moody, Chelsea Price, Hannah Reynolds, Will Torres, Colby White, and Haiyong Xu. To my husband, Neel, I could not have done this without your loving support. You bring me joy and comfort daily and I appreciate the countless things you have done to help me throughout graduate school. I am very fortunate to have wonderful parents and I thank you both for your unconditional love and for always letting me know how much you care. Thanks also to Lindsay, Brooke, Pat, Steve, as well as other family and friends not mentioned here that have supported me over the years. iii Table of Contents Dedication ........................................................................................................................... ii Acknowledgements ............................................................................................................ iii Table of Contents ............................................................................................................... iv List of Tables ...................................................................................................................... v List of Figures .................................................................................................................... vi Abstract .............................................................................................................................. ix Chapter 1: Introduction ....................................................................................................... 1 Thoracic Injury and Aging .............................................................................................. 1 Relevant Anatomy .......................................................................................................... 3 Medical Imaging ............................................................................................................. 5 Research Objectives ........................................................................................................ 6 References ....................................................................................................................... 7 Chapter 2: Image segmentation and registration algorithm to collect thoracic skeleton landmarks for age and gender characterization ................................................................ 10 Chapter 3: Morphometric analysis of variation in the ribs with age and gender .............. 37 Chapter 4: Morphometric analysis of variation in the sternum with age and gender ....... 81 Summary of Research ..................................................................................................... 118 Scholastic Vita ................................................................................................................ 119 iv List of Tables Table 1. Age of the appearance and the fusion of the sternal ossification centers in normal sternal development (Stark and Jaramillo 1986). ............................................................... 4 Table 2. Summary of subjects, ribs, and sternums included in the study. Registration and homologous landmark collection completion totals by age group are provided for the ribs and the sternum. ................................................................................................................ 24 Table 3. Deviation analysis results: The percentage of deviations greater than 1.5mm between the landmarks and the STL model was computed and quantiles summarizing these percentages for all 7,077 ribs and 187 sternums are reported. ................................ 26 Table 4. Regression coefficients and R2 values for the right male ribs (R1M-R12M) describing the posterior landmark location relative to the global SAE J211 coordinate system and Euler angles about the local rib coordinate system axes. Similar magnitudes and trends were observed for the left ribs (not reported). ................................................. 79 Table 5. Regression coefficients and R2 values for the right female ribs (R1F-R12F) describing the posterior landmark location relative to the global SAE J211 coordinate system and Euler angles about the local rib coordinate system axes. Similar magnitudes and trends were observed for the left ribs (not reported). ................................................. 80 Table 6. Publication plan for research outlined in this dissertation. ............................... 118 v List of Figures Figure 1. Thoracic skeleton anatomy including the ribs, sternum, costal cartilage, and the thoracic spine (Gayzik, Moreno et al. 2011). ...................................................................... 4 Figure 2. Segmentations of pediatric sternums with ossification center patterns characteristic of Type I, II, and III sternums (Ashley 1956). From left to right: Type I sternum of a 6 month female. Type II sternum of an 8 month female. Type III sternum of a 1 year old female. ............................................................................................................. 5 Figure 3. 3D CT reconstructions (left to right): 6, 29, and 73 year old subjects. Morphological thoracic skeletal differences of the pediatric, young adult, and elderly subjects are evident. ............................................................................................................ 6 Figure 4. 3D CT reconstructions (top to bottom): 6, 29, and 73 year old subjects. Morphological thoracic skeletal differences of the pediatric, young adult, and elderly subjects are evident. .......................................................................................................... 16 Figure 5. A) Thoracic skeleton anatomy including the ribs, sternum, costal cartilage, and the thoracic spine (Gayzik et al., 2011). B) 3D models of the 24 ribs and sternum obtained from the segmentation of a chest CT of a 23 year old male subject. ................. 18 Figure 6. The surface areas and number of landmarks placed for the rib and sternum atlases. Grids of landmarks were placed at an even spacing of 1.7 mm such that more landmarks were placed on structures with larger surface areas. ....................................... 19 Figure 7. Rigid, affine, and nonlinear transforms (TFMs) applied to the right sixth rib of a 23 year old subject to register the atlas rib landmarks to the subject rib. Only 1,000 landmarks are visualized in this example. ........................................................................ 21 Figure 8. The number of unique subjects that were used to register and collect homologous landmarks for each rib. The x-axis indicates the rib (right ribs 1-12: R1-R12; left ribs 1-12: L1-L12). ..................................................................................................... 25 Figure 9. Deviation analysis results for a 23 year old male subject with color bar indicating differences in millimeters. The average of all the deviations was 0.044 mm (0.378 mm average for the positive deviations and -0.319 mm for the negative deviations) with a standard deviation of 0.561 mm. ............................................................................ 27 Figure 10. a) Example of the initial difference in coordinate systems for one subject and the atlas. b) Posterior view of the right and left sixth ribs (R6 and L6) and the right seventh rib (R7) of the atlas. The landmarks selected on the posterior head of the three ribs to define the global coordinate basis are