Abstract

Chest X-ray (CXR), computed tomography (CT), and positron emission tomography–computed tomography (PET-CT) are noninvasive imaging techniques widely used in human and veterinary pulmonary research and medicine. These techniques have recently been applied in studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-exposed non-human primates (NHPs) to complement virological assessments with meaningful translational readouts of lung disease. Our review of the literature indicates that medical imaging of SARS-CoV-2-exposed NHPs enables high-resolution qualitative and quantitative characterization of disease otherwise clinically invisible and potentially provides user-independent and unbiased evaluation of medical countermeasures (MCMs). However, we also found high variability in image acquisition and analysis protocols among studies. These findings uncover an urgent need to improve standardization and ensure direct comparability across studies.

Results from MultiScan™ LFER PET/CT

• Desease detection and characterization

Figure 1 Comparison of chest X-ray (CXR), computed tomography (CT), and positron emission tomography–computed tomography (PET-CT) imaging.

To compare results in non-human primate (NHP) lungs after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure, images on the same row originate from the same animal and were obtained on the same day (day 4 post-exposure). For the animal in the upper row, the lesion located in the middle part of the left lung (marked by the crosshairs and arrows) is clearly visible using all three imaging modalities. By contrast, alterations in lung density for the animal shown in the bottom row could only be clearly distinguished from healthy lung using CT (marked by the crosshairs and arrows) but are hardly visible on CXR and PET-CT.

• Qualitative and quantitative analysis

Lung abnormalities detected by computed tomography (CT) matched with gross pathology.

Figure 3 Obtained just before euthanasia (day 7 post-exposure), these images were matched to gross pathology photographs. Lesions found reflecting the same location are marked with similarly colored circles.

more details in the original review article