Radiomics Evaluation of Multimodal (X-ray CT/SPECT/PET/MRI) in Vivo Imaging Results in Animal Models

Abstract

Multimodal in vivo (X-ray CT/SPECT/PET/MRI) fusion hybrid imaging provides quantitative, comparable, sensitive, longitudinal and robust data, revealing important anatomical and functional information, respectively. Radiomics data handling and evaluation is an approach to increase further the biological value of information obtained by in vivo imaging. These data can be either morphologic, results of biochemical reactions, as well as positions of moving organ’s time-related information. The purpose of radiomics is to increase reliability, precision, accuracy or robustness of data, or decrease sample number, respectively. The main goal of this study, was to examine and present a spectrum of radiomics-based imaging in animal experiments, with the opportunity to adapt it to individual clinical imaging or monitoring of environmental systems, respectively. In developed countries the diseases of locomotor- and the respiratory- system are among the major public health problems. The latter is exacerbated by air pollution. Apart from that, environmental pollution is continuously growing and it exerts harmful effects on mankind in multifarious ways. According to the estimations in 2004 in the US leading to approximately 1.5 million fractures, which required bone grafting in ca. 500.000 cases. According to the WHO in 2012 around 7 million people died as a result of air pollution, including 3.1 million premature deaths caused by indoor and urban outdoor air pollution. In 2016 the air pollution is estimated to reduce the average global life expectancy with 1 year. According to the EPA sulfur dioxide and ground-level ozone precursors (nitrogen oxides and volatile organic compounds) derived mainly from fuel combustion are among the most frequent health hazards. Mineral oil and heavy metals are waste products mostly of municipal, industrial and commercial sectors and they represent 60% of soil pollution. Among them Cd has the ability to accumulate with biomagnification process, the excretion of Cd is very slow but its deleterious effects are severe and multifarious. Therefore possible contamination with Cd requires to be minimized. Our research group has established in vivo animal models utilizing radiomicsbased evaluation to elucidate details of bone formation (bone graft healing) and airpollution related lung diseases. Also a novel in vivo imaging approach to detect the effect of soil pollutant Cd in earthworm (Eisenia hortensis and Lumbricus terrestris) was developed. Utilizing X-ray CT and MDP SPECT with radiomics-based evaluation enabled the statistically significant discerning of poly (methyl methacrylate)-based bone cement graft (PMMA) and albumin coated, sterilized, antigen-extracted freezedried human bone grafts (HLBC). With X-ray CT reconstructed attenuation corresponding specific voxel's fractal dimension distribution profile, abstracted their quantity with histograms, separated to Gaussian-curves with calculated descriptive parameters, the discerning from each other of a sulfur dioxide gas exposed, of an airdiluted fresh mainstream cigarette smoke mixed with ozone-air gas mixture treated, and also of a control group was enabled. Using in vivo earthworms, after proper immobilization, the early effect of Cd pollution was revealed with FDG PET/MRI modalities. Multiple testing with the same animal, combined with radiomics-based evaluation methods increased cost-effectivity and decreased the necessary sample number of animals, in coherence with the European Union (EU) directive 2010/63/EU on the protection of animals. The health hazards and diseases investigated in the present work are prime examples of high individual and societal costs both in quality of life and in financial sense. The combination of screening, imaging and radiomics-based monitoring offers and effective opportunity to diagnose early and treat properly the lung or bone diseases and also to minimize the exposure of environmental pollutions. Moreover the bone formation evaluation method as well as the attenuation value correlated FD distribution pattern analysis of the chest X-ray CT may be even adapted into clinical practice to monitor surgical, pharmaceutical, and physical therapies. The developed earthworm test system may enhance the required strict environmental monitoring. This can even underpin decisions to decrease Cd concentration with the extensive and costly soil replacement intervention, if it is necessary. The thesis also leads the way to further more widespread studies both in clinical prevention and environmental protection enhanced by radiomics evaluation methods of image data.