Preclinical In-Ovo Imaging Using Ostrich Eggs – Which Problems Have To Be Resolved And How?

Ziel/Aim A conceptual preclinical imaging method using ostrich (Struthio camelus) eggs and human imaging modalities (e.g. PET/CT) has been introduced in 2019; however, methodological problems were identified and announced to be subject of further studies.

Methodik/Methods We analyzed the major problems of 1) egg availability throughout the year, 2) optimization of incubation, 3) surveillance of correct embryonal development, 4) motion artifacts and 5) reproducibility of organ uptake. 20 ostrich eggs were used to test different methods.

Ergebnisse/Results 1) Literature research and contact to local expert veterinarians was established to investigate the egg availability. In Germany, ostrich eggs are available from April to September, thus, eggs of another large ratite bird, emu (Dromaius novohollandiae) were considered to ‘fill the gap’ as these birds breed from December until April. 2) Commercially available incubators automatically turn the eggs regularly, monitor air humidity and have a capacity of up to 80 ostrich eggs, enabling large numbers of experiments. 3) Regular CT scans are useful to differ between non-fertilized, fertilized and dead-in-shell eggs. 4) Motion artifacts on PET/CT scans can be reduced using inhalative narcotic gases available in clinical routine (e.g. isoflurane). 5) A PET/CT scan immediately followed by an autopsy is suited to ensure correct uptake measurements of ostrich organs.

Schlussfolgerungen/Conclusions Several methods were tested and identified to be suitable to solve methodological issues regarding preclinical imaging using ostrich eggs. Systematical evaluation of these methods is necessary to identify a robust protocol which can be used in different questions.