The importance of routine quality control for reproducible pulmonary measurements by in vivo micro-CT

Abstract

Micro-computed tomography (CT) imaging provides densitometric and functional assessment of lung diseases in animal models, playing a key role either in understanding disease progression or in drug discovery studies. The generation of reliable and reproducible experimental data is strictly dependent on a system’s stability. Quality controls (QC) are essential to monitor micro-CT performance but, although QC procedures are standardized and routinely employed in clinical practice, detailed guidelines for preclinical imaging are lacking. In this work, we propose a routine QC protocol for in vivo micro-CT, based on three commercial phantoms. To investigate the impact of a detected scanner drift on image post-processing, a retrospective analysis using twenty-two healthy mice was performed and lung density histograms used to compare the area under curve (AUC), the skewness and the kurtosis before and after the drift. As expected, statistically significant differences were found for all the selected parameters [AUC 532 ± 31 vs. 420 ± 38 (p < 0.001); skewness 2.3 ± 0.1 vs. 2.5 ± 0.1 (p < 0.001) and kurtosis 4.2 ± 0.3 vs. 5.1 ± 0.5 (p < 0.001)], confirming the importance of the designed QC procedure to obtain a reliable longitudinal quantification of disease progression and drug efficacy evaluation.

Micro-CT-assisted identification of the optimal time-window for antifibrotic treatment in a bleomycin mouse model of long-lasting pulmonary fibrosis

“…All experiments were carried out in accordance with the intramural animal welfare practices for animal experimentation of Chiesi Farmaceutici S.p.A. and complied with the European Directive 2010/63/UE, Italian D.Lgs 26/2014, the revised “Guide for the Care and Use of Laboratory Animals” (National Research Council Committee, US, 2011) 12 and in accordance with ARRIVE guidelines 13 . The study was conducted in an AAALAC (Association for Assessment and Accreditation for Laboratory Animal Care) certified facility at Chiesi Farmaceutici; all the experimental animal procedures used in the study were approved by the Italian Ministry of Health (protocol number n° 809/2020-PR) and by the internal AWB (Animal Welfare Body).…”

“…For each acquisition, two stacks of 512 cross-sectional images were automatically reconstructed into two 3D datasets corresponding to the inspiratory and expiratory breathing phases (i.e., end-inspiration, P01, and end-expiration, P02) with a 50 µm isotropic reconstructed voxel size, using a filtered back-projection algorithm with a Ram-Lak filter. The micro-CT scanner was calibrated monthly, using standard phantoms for noise, homogeneity, low contrast, and resolution 13 .…”

A fully automated micro‑CT deep learning approach for precision preclinical investigation of lung fibrosis progression and response to therapy

“…end-inspiration, P01, and end-expiration, P02), with 50 μm isotropic reconstructed voxel size. The CT scanner is calibrated monthly with standard phantoms for noise, uniformity, low contrast, and resolution [ 24 ].…”

Single, Double and Triple-hit Strategies to Establish a Long-term Premature Rabbit Model of Bronchopulmonary Dysplasia

“…V T, Minute Ventilation (MV), and BR were determined as previously described [30]. The CT scanner is calibrated monthly with standard phantoms for noise, uniformity, low contrast, and resolution [32].…”