Background and Aim: Ultrasound (US) imaging is increasingly preferred over other more invasive modalities in preclinical studies using animal models. However, this technique has some limitations, mainly related to operator dependence. To overcome some of the current drawbacks, sophisticated data processing models are proposed, in particular artificial intelligence models based on deep learning (DL) networks. This systematic review aims to overview the application of DL algorithms in assisting US analysis of images acquired in in vivo preclinical studies on animal models. Methods: A literature search was conducted using the Scopus and PubMed databases. Studies published from January 2012 to November 2022 that developed DL models on US images acquired in preclinical/animal experimental scenarios were eligible for inclusion. This review was conducted according to PRISMA guidelines. Results: Fifty-six studies were enrolled and classified into five groups based on the anatomical district in which the DL models were used. Sixteen studies focused on the cardiovascular system and fourteen on the abdominal organs. Five studies applied DL networks to images of the musculoskeletal system and eight investigations involved the brain. Thirteen papers, grouped under a miscellaneous category, proposed heterogeneous applications adopting DL systems. Our analysis also highlighted that murine models were the most common animals used in in vivo studies applying DL to US imaging. Conclusion: DL techniques show great potential in terms of US images acquired in preclinical studies using animal models. However, in this scenario, these techniques are still in their early stages, and there is room for improvement, such as sample sizes, data preprocessing, and model interpretability.

Lithium (Li) salts are commonly used as medications for bipolar disorders. In addition to its therapeutic value, Li is also being increasingly used as a battery component in modern electronic devices. Concerns about its toxicity and negative impact on the heart have recently been raised. We investigated the effects of long-term Li treatment on the heart, liver, and kidney in mice. Sixteen C57BL/6J mice were randomly assigned to receive oral administration of Li carbonate (n = 8) or act as a control group (n = 8) for 12 weeks. We evaluated the cardiac electrical activity, morphology and function, and pathways contributing to remodelling. We assessed the multi-organ toxicity using histopathology techniques in the heart, liver, and kidney. Our findings suggest that mice receiving Li had impaired systolic function and ventricular repolarisation and were more susceptible to arrhythmias under adrenergic stimulation. The Li treatment caused an increase in the cardiomyocytes’ size, the modulation of the extracellular signal-regulated kinase (ERK) pathway, along with some minor tissue damage. Our findings revealed a cardiotoxic effect of Li at therapeutic dosage, along with some histopathological alterations in the liver and kidney. In addition, our study suggests that our model could be used to test potential treatments for Li-induced cardiotoxicity.