Hounsfield units are a useful predictor of pleural effusion cytological type in dogs but not in cats.

All categories of pleural effusion subjectively display as soft tissue opacity on computed tomography (CT). Quantitative measurement using Hounsfield units (HU) has the potential to bring additional information regarding the nature of the fluid in a noninvasive way. The purposes of this retrospective cross-sectional analytical study were to compare Hounsfield units of different pleural effusion categories in dogs and cats, assess association between specific cytologic parameters and Hounsfield units, and evaluate the effect of dependent vs. nondependent aspect of the effusion pool on Hounsfield unit. A total of 111 patients (74 dogs and 37 cats) with pleural effusion, that underwent thoracic CT and diagnostic thoracocentesis, were included in the study. Effusions were cytologically categorized as exudate, transudate, modified transudate, hemorrhage, or chyle. Significant differences existed in Hounsfield units between categories in dogs (P < 0.0001) but not in cats (P = 0.334). Canine chylous effusion (6.1 ± 4.7 HU (mean ± standard deviation)) and transudate (5.6 ± 2.0) were significantly lower than exudate (20.3 ± 9.5) and hemorrhage (21.4 ± 9.2). No significant differences were found between modified transudate (13.6 ± 10.3) and other categories. Significant, weak linear correlation was identified in dogs between Hounsfield units and total protein (P = 0.018, R2  = 0.089), red blood cells (P = 0.021, R2  = 0.077), and total nucleated cells (P = 0.013, R2  = 0.089). The Hounsfield units of dependent effusion was not significantly higher than the nondependent effusion, except for canine chylous effusion (P = 0.008). Fourteen Hounsfield units was identified as the most clinically useful threshold: <14 HU identified transudate or chylous effusion with a sensitivity of 100% and a specificity of 69%. A threshold >14 HU had a specificity of 100% and a sensitivity of 69% for identifying exudate, modified transudate, or hemorrhage.

Ultrasonography does not consistently detect parathyroid glands in healthy cats.

Ultrasound is used to evaluate the parathyroid glands of several species but there are limited reports of its use in cats. With this prospective anatomic study, we hypothesized that ultrasound could identify two parathyroid glands as hypoechoic nodules associated with each thyroid lobe and that a normal size range could be established. Six cat cadavers were imaged with ultrasound and histopathology of the thyroid and parathyroid tissue was performed for comparison. In addition, clinically healthy adult cats were prospectively recruited and placed in Group 1 (2-6 years; n = 11) or Group 2 (7-13 years; n = 9). Ultrasound of the cervical region was performed using a 7-15 MHz linear transducer. Number, size, and location of all hypoechoic nodules within or immediately adjacent to the thyroid lobes were documented. Ultrasound identified between 0-6 hypoechoic nodules per thyroid lobe in cat cadavers and between 0-3 hypoechoic nodules per thyroid lobe in clinically healthy cats, which does not correlate with the normal anatomy. In conclusion, parathyroid glands were frequently not ultrasonographically observed or were not distinguishable from thyroid tissue and this problem was worse in older cats because of the prevalence of nodular thyroid lesions, which primarily included foci of adenomatous hyperplasia.

Presumptive keratoglobus in a great horned owl (Bubo virginianus).

A juvenile to young adult, male, great horned owl (Bubo virginianus,GHOW) was presented to the wildlife rehabilitation hospital at Lindsay Wildlife Museum (WRHLWM) due to trauma to the right patagium from barbed wire entanglement. On presentation, both corneas were irregular, dry, and no movement of the third eyelid was noted. A severe corneal enlargement/globoid appearance was the predominant ophthalmic feature. The fundus was normal in both eyes (OU). Over the course of several days, both corneas developed edema combined with further dessication at the ocular surface associated with diffuse dorsal fluorescein stain uptake. Repeated ophthalmic examinations found normal intraocular pressures and an inability to move the third eyelid over the enlarged corneas. The bird was deemed nonreleasable due to severe wing damage and poor prognosis associated with eye abnormalities and was humanely euthanized. Postmortem CT, enucleation, and histopathology were performed to evaluate the ocular anatomical abnormality and confirm the suspected diagnosis of keratoglobus. This GHOW represents the first reported case of presumptive keratoglobus in a raptor.