Shear wave elastography is a novel technique enabling real-time measurement of the elasticity of liver tissue. The color map is superimposed on the classic ultrasound image of the assessed tissue, which enables a precise evaluation of the stiffness of the liver tissue. The aim of the study was to assess the stiffness of normal liver tissue in the guinea pig using shear wave elastography. The study was carried out on 36 guinea pigs using the SuperSonic Imagine Aixplorer scanner, and a 1 to 6 MH convex SC6-1 transducer. An ultrasound guided Try-Cut liver core needle biopsy was carried out in all the studied animals and the collected samples were examined to exclude pathological lesions. The mean liver tissue stiffness ranged from 0.89 to 5.40 kPa. We found that shear wave elastography is an easy, non-invasive technique that can be used to assess the stiffness of liver tissue. The obtained results can be used in future studies to assess the types and changes of liver tissue in the course of various types of liver disease.

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Background Magnetic resonance imaging using gadoxetic acid, a hepatocyte-specific contrast agent, is one of the most useful MRI techniques used to diagnose liver tumours in humans. During the hepato-biliary phase, there is uptake of gadoxetic acid by normal hepatocytes, leading to hepatic parenchymal enhancement. This feature is used in human medicine to diagnose hepatic parenchymal metastatic disease, to differentiate primary liver tumours, to diagnose liver cirrhosis and focal nodular hyperplasia. This study presents the preliminary results of magnetic resonance imaging of focal lesions localised in the liver parenchyma in dogs following the administration of gadoxetic acid. Results The lesion enhancement ratio (ER lesion ) in the tumour metastasis was 0.05; the liver enhancement ratio (ER liver ) – 0.49 and the post-contrast lesion-to-liver contrast ratio (CR) was 0.17. In dogs with hepatocellular hyperplasia, these values were 0.54; 0.51; and 1.18, respectively. In two dogs with a hepatic adenoma, the ER lesion was 0.26 and 0.17, respectively; the ER liver was 0.47 and 0.47, respectively and the CR was 0.33 and 0.31, respectively. In the dog with a neuroendocrine tumour, the ER lesion was 0.03; the ER liver amounted to 0.58 and the CR was 0.35. In the case of a hepatocellular carcinoma, these coefficients were 0.2, 0.6 and 0.3, respectively. Conclusion Based on the results, it may be assumed that the MR images of the proliferative hepatic parenchymal lesions in dogs using gadoxetic acid are similar to those obtained in humans. This suggests that the contrast enhancement patterns used in human medicine may be useful in differentiating hepatic parenchymal lesions in dogs.

The aim of the study was to assess pH, pO 2 and pCO 2 in peritoneal fluid. The study was conducted on a group of 22 dogs with symptoms of ascites. Group 1 consisted of 4 dogs with adenocarcinoma, group 2 -of 6 dogs with glomerulonephritis, group 3 of 8 dogs with hepatic cirrhosis and group 4 of 4 dogs with bacterial peritonitis. An abdominal cavity puncture was performed in all dogs and the fluid was drawn into a heparinized syringe in order to assess pH, pO 2 and pCO 2 . The analysis of pH in the peritoneal fluid revealed statistically significant differences between group 4 and groups 1 (p=0.01), 2 (p=0.01), and 3 (p=0.01). The lowest pH value compared to the other studied groups was recorded in group 4. In group 4, the pO 2 was the lowest compared to the other groups (group 1 p=0.01, group 2 p=0.01, group 3 p=0.01). The value of pCO 2 was the highest in group 4 compared to groups 1, 2, and 3. The study found statistically significant differences in pH, pO 2 and pCO 2 between group 4 (the group of dogs with bacterial peritonitis) and the other groups of dogs. This was probably linked to the pathogenesis of peritonitis. As a result of an inflammatory reaction within the peritoneal cavity, there is an increase in fibrin accumulations leading to a decreased oxygen supply causing the oxidative glucose metabolism to change into a non-oxidative glucose metabolism. This, in turn, causes a decrease in pH, acidosis, and a low oxidoreduction potential. It also impairs phagocytosis and activates proteolytic enzymes which create ideal conditions for the growth of anaerobic bacteria. The obtained results indicate that the pH, pO 2 and pCO 2 may be used to differentiate bacterial peritonitis from ascites of other etiologies.

The aim of this study was to describe a core needle biopsy technique in the guinea pig ( Cavia porcellus ) and to assess the incidence of complications when applying this method. Biopsies were taken from the right hepatic lobe of 36 healthy guinea pigs under ultrasound guidance using a Tru-Cut needle. There were no immediate complications in 35 animals but ultrasound images showed a haemorrhage from the biopsy site in one guinea pig. The haemorrhage stopped after administering a sterile cooling dressing. One guinea pig died 13 days after the biopsy due to late complications. The procedure is in some animals associated with severe, potential life-threatening, complications. Assessment of the biopsy site by ultrasonography for 30 min after the procedure is recommended to allow timely handling of haemorrhage. The procedure is not recommended in animals with a suspected coagulopathy. Due to the risk of severe complications, this procedure should be restricted to guinea pigs where the result of the biopsy examination is expected to be valuable for the choice of treatment or prognosis. Owners should be made aware of the risks associated with the procedure. Electronic supplementary material The online version of this article (10.1186/s13028-019-0462-4) contains supplementary material, which is available to authorized users.