Abstract: Purpose This research aimed at developing a software tool for the purposes of quantifying and visualizing HIV-associated lipodystrophy from full body magnetic resonance imaging (MRI) datasets. The primary goal for developing the software tool was to create and compare the results gathered from MRI to those from the current …
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Abstract: Purpose This research aimed at developing a software tool for the purposes of quantifying and visualizing HIV-associated lipodystrophy from full body magnetic resonance imaging (MRI) datasets. The primary goal for developing the software tool was to create and compare the results gathered from MRI to those from the current gold standard, dualenergy X-ray absorptiometry (DEXA). A software based solution for this purpose is proposed and a full evaluation with the intention of future clinical use is presented. The additional aim of volume visualization in order to assess the external morphological effects of HIV-associated lipodystrophy is also presented. Methods The data gathered for this study involved a cohort of HIV positive cases (n = 8) which were 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 was identified as one the key components of this piece of research. A fully automatic segmentation algorithm was implemented for this purpose. Quantification of segmented adipose 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 and performance. In order to evaluate the clinical relevance of the results of segmentation, a comparison 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 also presented. Visualization of adipose distribution and external morphology from full body data were also identified as an important component of this project. A surface based volume visualization technique was implemented in order to allow users to view a patient’s external morphology. Application of a heat map to the surface in order to intuitively visualize the distribution of adipose tissue was also implemented. Results The findings of this study indicate that the results gathered by the software tool developed compared well to those of the current gold standard. A strong correlation between the results of the two modalities was found with a correlation coefficient r of 0.68 and significance level of p < 0.0001 with a very small 95% confidence interval. A reasonable level of agreement between the modalities was also recorded, the mean difference 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 Imaging MRI 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. Conclusions In this study the segmentation, quantification and visualization of adipose tissue from full body 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 for accuracy 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.
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