Can distinction between the renalcortex and outer medulla onultrasonography predict estimatedglomerular filtration rate in caninechronic kidney diseases?

Background@#Quantitative evaluation of renal cortical echogenicity (RCE) has been tried anddeveloped in human and veterinary medicine. @*Objectives@#The objective of this study was to propose a method for evaluating RCEquantitatively and intuitively, and to determine associations between ultrasonographic renalstructural distinction and estimated glomerular filtration rate (eGFR) in canine chronickidney disease (CKD). @*Methods@#Data were collected on 63 dogs, including 27 with normal kidney function and 36CKD patients. Symmetric dimethylarginine and creatinine concentrations were measuredfor calculating eGFR. RCE was evaluated as 3 grades on ultrasonography images accordingto the distinction between the renal cortex and outer medulla. The RCE grade of each kidneywas measured. @*Results@#There was a significant difference in eGFR between the group normal and CKD (p< 0.001). As mean of RCE grades (the mean values of each right and left kidney's RCE grade)increases, the proportion of group CKD among the patients in each grade increases (p <0.001). Also, severity of RCE (classified as "high" if any right or left kidney evaluated as RCEgrade 3, "low" otherwise) and eGFR is good indicator for predicting group CKD (p < 0.001). @*Conclusions@#The degree of distinction between the renal cortex and the outer medulla isclosely related to renal function including eGFR and the RCE grade defined in this study canbe used as a method of objectively evaluating RCE.

Usefulness of a saline chaser to reduce contrast material dose in abdominal CT of normal dogs

Use of a saline chaser has been reported to allow reduction of contrast dose and artifacts during computed tomography (CT) examination in humans. This study assesses the extent of contrast dose by using a saline chaser in abdominal CT scans of normal dogs. Five beagles underwent abdominal CT scans. Three protocols were applied: 600 mg I/kg iohexol without saline chaser (protocol 1), 30% lower dose of iohexol (420 mg I/kg) followed by a 10 mL saline chaser (protocol 2), and 40% lower dose of iohexol (360 mg I/kg) followed by a 10 mL saline chaser (protocol 3). Attenuation values were obtained from aorta, portal vein, and liver parenchyma. The maximum enhancement values (MEVs) in protocol 2 were significantly higher than those in protocols 1 and 3 in the aorta; no difference was seen in the portal vein in all protocols. The liver parenchymal MEVs in protocols 1 and 2 were significantly higher than those obtained in protocol 3. In this study, the use of a saline chaser and a reduced dose of contrast material did not affect vessel enhancement. In conclusion, use of a saline chaser for abdominal CT of dogs is recommended because it allows a 30% reduction of contrast dose without decreasing vascular and hepatic parenchymal enhancement.