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

• Published in: Veterinary radiology & ultrasound 2018-07, Vol.59 (4), p.405-411
• Main Authors: Woods, Sarah J., Spriet, Mathieu, Safra, Noa, Cissell, Derek D., Borjesson, Dori L.
• Format: Article
• Language: English
• Subjects: Animals; Cat Diseases - diagnostic imaging; Cats; chyle; computed tomography; Cross-Sectional Studies; Dog Diseases - diagnostic imaging; Dogs; exudate; Exudates and Transudates - diagnostic imaging; hemorrhage; Pleural Effusion - diagnostic imaging; Pleural Effusion - veterinary; Radiography, Thoracic - methods; Radiography, Thoracic - veterinary; Retrospective Studies; Sensitivity and Specificity; Species Specificity; Tomography, X-Ray Computed - methods; Tomography, X-Ray Computed - veterinary; transudate
• ISSN: 1058-8183; 1740-8261
• DOI: 10.1111/vru.12618

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