Background: Renal cystic disease arising from various etiologies results in fluid-filled cavities within the kidneys. Moreover, preexisting renal dysfunction has been shown to exacerbate multiple pathologies. While swine bred for biomedical research are often clinically inspected for illness/parasites, more advanced diagnostics may aid in uncovering underlying renal abnormalities. Methods: Computed tomography was performed in 54 female prepubertal Yorkshire swine to characterize renal cysts; urine and blood chemistry, and histology of cysts were also performed. Results: Digital reconstruction of right and left kidneys demonstrated that roughly one-third of the animals (17/54; 31%) had one or more renal cyst. Circulating biomarkers of renal function were not different between animals that had cysts and those that did not. Alternatively, urinary glucose (P = .03) was higher and sodium (P = .07) tended to be lower in animals with cysts compared to animals without, with no differences in protein (P = .14) or potassium (P = .20). Aspiration of cystic fluid was feasible in two animals, which revealed that the cystic fluid urea nitrogen (97.6 ± 28.7 vs 911.3 ± 468.2 mg/dL), potassium (29.8 ± 14.4 vs 148.2 ± 24.85 mmol/L), uric acid (2.55 ± 1.35 vs 11.4 ± 5.65 mg/dL), and creatinine (60.34 ± 17.26 vs 268.99 ± 95.79 mg/dL) were much lower than in the urine. Histology demonstrated a cyst that markedly compresses the adjacent cortex and is lined by a single layer of flattened epithelium, bounded by fibrous connective tissue which extends into the parenchyma. There is tubular atrophy and loss in these areas. Conclusion: This study provides valuable insight for future studies focusing on kidney function in swine bred for biomedical research.

IntroductionAcute Respiratory Distress Syndrome (ARDS) is characterized by impairment of gas exchange, lung edema and diffuse density changes on computed tomography (CT). We sought to measure lung weight through a simplified, semi‐automated method of quantitative CT scan analysis (qCT) in order to quantify lung edema.MethodsChest CT scans were performed in 6 pigs (46±2 kg). Five pigs had ARDS due to smoke inhalation and 40% total body surface area cutaneous burn; 1 was a healthy control. CT images were reconstructed at 2 mm thickness with a step of 20 mm, yielding 15±2 images per series. Lung weight was estimated with image‐analysis software (Maluna, Goettingen, Germany) assuming 1.06 as lung‐specific weight. After necropsy, lungs were weighed on a balance to assess agreement between qCT and post‐mortem lung weight via Bland‐Altman analysis.ResultsLung weights ranged from 237 to 1463 g (mean 1003 g) at necropsy and from 356 to 1411 g (mean 1066 g) at qCT. A high correlation (r2=0.98, p=0.0001) was observed between the two methods. Bland‐Altman analysis showed a bias of −63.5 g with limits of agreement of 60 and −186.ConclusionsLung weight can be accurately measured in vivo via qCT. Quantitative CT analysis may be a useful tool to evaluate and monitor the time course of lung edema in ARDS.Source of research support: Institute of Surgical Research, Fort Sam Houston, TX

Computed tomographic myocardial perfusion (CTP) imaging is a tool that shows promise in emergent settings for defining the hemodynamic significance of coronary artery disease. In this study, we examined the accuracy with which the transmural perfusion ratio (TPR) derived through semiautomated CTP analysis reflected segmental perfusion defects associated with intermediate coronary artery lesions in swine. Lesions (diameter stenosis, 65% ± 11%) of the left anterior descending coronary artery (LAD) were created in 10 anesthetized female swine (weight, 47.5 ± 1.9 kg) by using a pneumatic occlusion device implanted on the LAD. Occluder inflation pressures were adjusted to maintain fractional flow reserve (FFR, 74.3 ± 1.7) during adenosine infusion (140ug/kg/min). Static CTP imaging using a stress-rest protocol and segmental TPR derived from semiautomated CT perfusion software was compared with microsphere-derived TPR (mTPR) by using a 16-segment model and polar mapping. Intermediate LAD stenosis was verified through multiplanar coronary CT angiography. Receiver operating characteristic analysis identified an optimal threshold for segmental perfusion defects for intermediate lesions (TPR threshold, ≤0.80); however, the area under the receiver operating characteristic curve was 0.58, and the overall accuracy was 63%. At this threshold, the sensitivity and specificity were 65% and 61%, and the positive and negative predictive values were 61% and 65%, respectively. Although CTP–TPR illustrated segmental perfusion defects with intermediate lesions, the disparity between CTP–TPR and mTPR measures of segmental perfusion suggests that further advances in analysis software may be necessary to improve the localization of segmental defects for intermediated lesions.