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.

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.
Abdomen ; Animals ; Aorta ; Artifacts ; Dogs ; Humans ; Iohexol ; Liver ; Portal Vein ; Tomography, X-Ray Computed