Correlation between caudal pulmonary artery diameter to body surface area ratio and echocardiography-estimated systolic pulmonary arterial pressure in dogs

Caudal pulmonary artery diameter (CPAD) to body surface area (BSA) ratios were measured in ventrodorsal thoracic radiographs to assess the correlation between CPAD to BSA ratios and systolic pulmonary arterial pressure (PAP) in dogs. Thoracic radiographs of 44 dogs with systolic pulmonary arterial hypertension (PAH) and 55 normal dogs were evaluated. Systolic PAP was estimated by Doppler echocardiography. CPADs were measured at their largest point at the level of tracheal bifurcation on ventrodorsal radiographs. Both right and left CPAD to BSA ratios were significantly higher in the PAH group than in the normal group (p < 0.0001). Linear regression analysis showed positive associations between PAP and right and left CPAD to BSA ratio (right, p = 0.0230; left, p = 0.0012). The receiver operating characteristic curve analysis revealed that the CPAD to BSA ratio had moderate diagnostic accuracy for detecting PAH. The operating point, sensitivity, specificity, and area under the curve were 28.35, 81.40%, 81.82%, and 0.870; respectively, for the right side and 26.92, 80.00%, 66.67%, and 0.822, respectively, for the left. The significant correlation of CPAD to BSA ratio with echocardiography-estimated systolic PAP supports its use in identifying PAH on survey thoracic radiographs in dogs.

Quantitative CT assessment of bone mineral density in dogs with hyperadrenocorticism

Canine hyperadrenocorticism (HAC) is one of the most common causes of general osteopenia. In this study, quantitative computed tomography (QCT) was used to compare the bone mineral densities (BMD) between 39 normal dogs and 8 dogs with HAC (6 pituitary-dependent hyperadrenocorticism [PDH]; pituitary dependent hyperadrenocorticism, 2 adrenal hyperadrenocorticism [ADH]; adrenal dependent hyperadrenocorticism) diagnosed through hormonal assay. A computed tomogaraphy scan of the 12th thoracic to 7th lumbar vertebra was performed and the region of interest was drawn in each trabecular and cortical bone. Mean Hounsfield unit values were converted to equivalent BMD with bone-density phantom by linear regression analysis. The converted mean trabecular BMDs were significantly lower than those of normal dogs. ADH dogs showed significantly lower BMDs at cortical bone than normal dogs. Mean trabecular BMDs of dogs with PDH using QCT were significantly lower than those of normal dogs, and both mean trabecular and cortical BMDs in dogs with ADH were significantly lower than those of normal dogs. Taken together, these findings indicate that QCT is useful to assess BMD in dogs with HAC.