Computed tomographic quantitative evaluation of common bile duct size in normal dogs: A reference range study considering body weight

Abstract

IntroductionCommon bile duct (CBD) measurements are important for the evaluation of biliary systemic disorders. However, in veterinary medicine, reference ranges for specific body weights (BW) and correlation between CBD diameter and BW have not been studied. This study aimed to establish normal reference ranges of CBD diameter for different BW groups and to analyse correlation between CBD diameter and BW in dogs without hepatobiliary disease. Additionally, normal reference ranges of CBD to aorta ratio (CBD: Ao ratio) were established which is not affected by BW.MethodsCBD diameter was measured at three different sites: porta hepatis (PH), duodenal papilla (DP) level and mid-portion (Mid) between these points using computed tomography (CT) in 283 dogs without hepatobiliary disease.ResultsThe reference range of CBD diameter at PH level: 1.69 ± 0.29 mm (Class 1; 1 kg ≤ BW < 5 kg), 1.92 ± 0.35 mm (Class 2; 5 kg ≤ BW < 10 kg), 2.20 ± 0.43 mm (Class 3; 10 kg ≤ BW < 15 kg), 2.79 ± 0.49 mm (Class 4; 15 kg ≤ BW < 30 kg); Mid-level: 2.06 ± 0.25 mm (Class 1), 2.43 ± 0.37 mm (Class 2), 2.74 ± 0.52 mm (Class 3), 3.14 ± 0.44 mm (Class 4); DP level: 2.33 ± 0.34 mm (Class 1), 2.90 ± 0.36 mm (Class 2), 3.35 ± 0.49 mm (Class 3), and 3.83 ± 0.50 mm (Class 4). There was a significant difference in CBD diameter at each level among all BW groups. Furthermore, BW and CBD diameter showed positive linear correlation at each level. We devised CBD: Ao ratio at each level that showed no significant difference between the different BW groups; PH level: 0.34 ± 0.05; Mid-level: 0.42 ± 0.06; DP level: 0.47 ± 0.06.ConclusionIn conclusion, since the CBD diameter for each BW is significantly different, different normal reference ranges of CBD diameter should be applied for each BW, and the CBD: Ao ratio can be used regardless of the BW.

Feasibility of Magnetic Resonance Cholangiopancreatography in Dogs—A Post-Mortem Study

“…The age of the dogs in that study varied between 0.5 and 17 years (mean 8.8 years). No correlation was found between CBD diameter and dog age, but there was a significant difference in the CBD diameter at each measurement point between body weight groups [35]. Furthermore, the body weight and CBD diameter showed a positive linear correlation at each point.…”

“…The discrepancy between the diameter measurements of the CBD obtained in our study and the previously reported measurements is likely due to the fact that the measurements were performed by different imaging modalities in dogs with varying body weights. Even though age of the dog has not been found to be related to the CBD diameter [35], the effect of old age on the measurements remains unknown. The youngest dog in our study was 9 years old.…”

“…The CBD diameter in seven healthy beagle dogs with a mean body weight of 14.1 ± 3 kg was earlier measured in ERCP with a measurement of 3.04 ± 1.89 mm at the duodenal papilla [16]. Recently, the CBD diameter at the porta hepatis, duodenal papilla level, and mid-portion was assessed using computed tomography in 283 healthy dogs weighing 1.5 to 29.5 kg [35]. The age of the dogs in that study varied between 0.5 and 17 years (mean 8.8 years).…”