Variation in fat content between liver lobes and comparison with histopathological scores in dairy cows with fatty liver

BACKGROUND: The assessment of a liver biopsy remains the gold standard for diagnosing and staging fatty liver in dairy cows, which is often necessary for diagnostic and research purposes. Accuracy of the diagnosis relays on the quality of the biopsy, the assumed representativeness of a small tissue sample for a disease process throughout the liver and accurate human evaluation of histologic specimens. The objective of the present study was to assess the distribution of triacylglycerol (TAG) infiltration throughout the parenchyma of livers with different degrees of fatty liver in dairy cows. In addition, histopathological scores from the corresponding specimens were compared to a quantitative measurement of TAG, as well as the agreement between two observers. METHODS: Thirty livers with different degrees of lipid infiltration were selected and 10 different locations throughout the liver were assessed. The TAG content was measured enzymatically, calculated in % or mg/g wet weight, and assigned to a scoring system. Corresponding tissue specimens were stained with hematoxylin-eosin (H&E) and Oil red O (ORO) for histopathological evaluation, using a scoring system. RESULTS: The difference in TAG content between any locations was less than 2%. Based on the scoring system the TAG concentration was even distributed in 79.3% of the livers. Based on kappa statistics the agreement between two pathologists and staining technique in scoring histological specimens was moderate to fair. CONCLUSIONS: Overall the distribution of TAG throughout the liver and the accuracy of human evaluation of liver biopsies may lead to acceptable diagnoses for clinical purposes. Within the liver lobules a common pattern of lipid distribution depending on severity could be observed. For the staging of lipid infiltration for research projects, some degree of variation needs to be considered

Effects of contrast medium injection technique on attenuation values of adrenal glands in healthy dogs during contrast-enhanced computed tomography

Abstract OBJECTIVE To assess the effects of 3 contrast medium injection techniques on attenuation values for canine adrenal glands during contrast-enhanced CT. ANIMALS 9 healthy Beagles. PROCEDURES 3 protocols were evaluated in a randomized cross-over design study: 700 mg of iodine/kg at a constant injection rate over 20 seconds (full-dose constant rate), the same dose at a rate following an exponential decay curve over 20 seconds (full-dose decelerated rate), and 350 mg of iodine/kg at a constant injection rate over 10 seconds (half-dose constant rate). Multislice CT images were obtained before and at predetermined time points after the start of contrast medium injection. RESULTS Median peak attenuation values were 129, 133, and 87 Hounsfield units with the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injection protocols, respectively. Peak attenuation differed significantly between the full-dose constant rate and half-dose constant rate injection protocols and between the full-dose decelerated rate and half-dose constant rate injection protocols. Median time to peak attenuation did not differ significantly among injection methods and was 30, 23, and 15 seconds for the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injections, respectively. CONCLUSIONS AND CLINICAL RELEVANCE The dose of contrast medium and the timing of postinjection CT scanning were main determinants of peak attenuation for adrenal glands in healthy dogs; effects of the 3 injection protocols on attenuation were minor. The exponentially decelerated injection method was subjectively complex. A constant injection protocol delivering 700 mg of iodine/kg over 20 seconds, with scans obtained approximately 30 seconds after starting contrast medium injection, provided images with maximum adrenal gland attenuation values. (Am J Vet Res 2016;77:144–150)</jats:p

Effects of contrast medium injection technique on attenuation values of adrenal glands in healthy dogs during contrast-enhanced computed tomography

OBJECTIVE: To assess the effects of 3 contrast medium injection techniques on attenuation values for canine adrenal glands during contrast-enhanced CT. ANIMALS 9 healthy Beagles. PROCEDURES: 3 protocols were evaluated in a randomized cross-over design study: 700 mg of iodine/kg at a constant injection rate over 20 seconds (full-dose constant rate), the same dose at a rate following an exponential decay curve over 20 seconds (full-dose decelerated rate), and 350 mg of iodine/kg at a constant injection rate over 10 seconds (half-dose constant rate). Multislice CT images were obtained before and at predetermined time points after the start of contrast medium injection. RESULTS: Median peak attenuation values were 129, 133, and 87 Hounsfield units with the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injection protocols, respectively. Peak attenuation differed significantly between the full-dose constant rate and half-dose constant rate injection protocols and between the full-dose decelerated rate and half-dose constant rate injection protocols. Median time to peak attenuation did not differ significantly among injection methods and was 30, 23, and 15 seconds for the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injections, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The dose of contrast medium and the timing of postinjection CT scanning were main determinants of peak attenuation for adrenal glands in healthy dogs; effects of the 3 injection protocols on attenuation were minor. The exponentially decelerated injection method was subjectively complex. A constant injection protocol delivering 700 mg of iodine/kg over 20 seconds, with scans obtained approximately 30 seconds after starting contrast medium injection, provided images with maximum adrenal gland attenuation values