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  • Publication
    Visualization and quantification of HIV associated lipodystrophy from magnetic resonance images
    (University College Dublin. School of Medicine and Medical Science, 2012) ;
    PurposeThis research aimed at developing a software tool for the purposes of quantifying andvisualizing HIV-associated lipodystrophy from full body magnetic resonance imaging(MRI) datasets. The primary goal for developing the software tool was to create andcompare the results gathered from MRI to those from the current gold standard, dualenergy X-ray absorptiometry (DEXA). A software based solution for this purpose isproposed and a full evaluation with the intention of future clinical use is presented. Theadditional aim of volume visualization in order to assess the external morphologicaleffects of HIV-associated lipodystrophy is also presented.MethodsThe data gathered for this study involved a cohort of HIV positive cases (n = 8) whichwere recruited in order to be scanned by both Dual Energy X-ray Absorptiometry(DEXA) and MRI techniques to facilitate comparison between the two modalities.The accurate identification and segmentation of adipose tissue from MRI datasets wasidentified as one the key components of this piece of research. A fully automaticsegmentation algorithm was implemented for this purpose. Quantification of segmentedadipose tissue and surface based volume visualization were implemented as the primary features of the software tool.The fully automatic segmentation algorithm was investigated in regards to accuracy andperformance. In order to evaluate the clinical relevance of the results of segmentation, acomparison of the results to those of the current gold standard (DEXA) was performed.Clinical feedback regarding the usefulness of the software tool in a clinical setting is alsopresented.Visualization of adipose distribution and external morphology from full body data werealso identified as an important component of this project. A surface based volumevisualization technique was implemented in order to allow users to view a patient’sexternal morphology. Application of a heat map to the surface in order to intuitivelyvisualize the distribution of adipose tissue was also implemented.ResultsThe findings of this study indicate that the results gathered by the software tooldeveloped compared well to those of the current gold standard. A strong correlationbetween the results of the two modalities was found with a correlation coefficient r of0.68 and significance level of p < 0.0001 with a very small 95% confidence interval. Areasonable level of agreement between the modalities was also recorded, the meandifference in fat measurements between the two was 5.62%. A panel of MR experts,Radiology (n = 2), MSc MRI Radiography Specialists (n = 3), PhD Medical ImagingMRI Specialists (n = 2) evaluated the segmentation technique used and it was found to be accurate and, due to the fact it was automatic, its results were 100% reproducible.ConclusionsIn this study the segmentation, quantification and visualization of adipose tissue from fullbody MRI dataset in place of the current gold standards was targeted and investigated.A proof of concept software tool was developed for this purpose and was evaluated foraccuracy and clinical relevance. The findings presented provide the evidence base that an appropriate tool was developed and could be used with MRI as an alternative to DEXA examination.
  • Publication
    Current Challenges and Future Research Areas for Digital Forensic Investigation
    Given the ever-increasing prevalence of technology in modern life, there is a corresponding increase in the likelihood of digital devices being pertinent to a criminal investigation or civil litigation. As a direct consequence, the number of investigations requiring digital forensic expertise is resulting in huge digital evidence backlogs being encountered by law enforcement agencies throughout the world. It can be anticipated that the number of cases requiring digital forensic analysis will greatly increase in the future. It is also likely that each case will require the analysis of an increasing number of devices including computers, smartphones, tablets, cloud-based services, Internet of Things devices, wearables, etc. The variety of new digital evidence sources poses new and challenging problems for the digital investigator from an identification, acquisition, storage and analysis perspective. This paper explores the current challenges contributing to the backlog in digital forensics from a technical standpoint and outlines a number of future research topics that could greatly contribute to a more efficient digital forensic process.