A Computed Tomographic Study of Volume and X‐ray Attenuation of the Lungs of Beagles in Various Body Positions

Abstract

The influence of body position on volume and x-ray attenuation of the lungs of three Beagles was investigated with computed tomography. In left and-right lateral recumbency, the dependent lung had decreased volume and increased x-ray attenuation compared with ventral recumbency. Volume and x-ray attenuation of the nondependent lung, however, were unchanged. In dorsal recumbency, there was a vertical gradient of x-ray attenuation being increased dorsally and decreased ventrally compared with ventral recumbency where regional differences in x-ray attenuation were not found. Result's indicate a risk of overlooking a mass in the dependent pulmonary parenchyma of dogs in lateral and dorsal recumbency. Regional differences in x-ray attenuation of the lungs of dogs can be avoided if the radiographs are obtained with the dog in ventral recumbency.

Qualitative and quantitative interpretation of computed tomography of the lungs in healthy neonatal foals

“…This finding is similar to that observed in dogs that undergo CT scanning in sternal recumbency and may represent compression of the lungs by the heart. 39,40 The older group of study foals had lower quantitative lung attenuation values than did the younger group. A similar difference has also been noted in pediatric humans over a much larger age range.…”

“…[36][37][38][39][40] Atelectasis can interfere with accurate evaluation of CT images and characterization of disease distribution and severity. A primary reason for the development of atelectasis in patients undergoing CT imaging 21 is the use of sedation or anesthesia in spontaneously breathing or ventilated subjects.…”

Effects of body position and extension of the neck and extremities on lung volume measured via computed tomography in red-eared slider turtles (Trachemys scripta elegans)

“…[14][15][16] For example, compression of the dependent lung tissue and loss of ventilation, with subsequent image contrast reduction, have been reported as an underlying cause for obscuring of focal pulmonary lesions because of border effacement (silhouette effect) in dogs and humans. A similar phenomenon has been shown in other animals positioned in vertical lateral recumbency for thoracic radiographic imaging.…”

“…2,3,10 Standard radiography and CT of the lungs are important and frequently performed techniques used for determination of the presence and severity as well as localization of lower respiratory tract disease. [12][13][14][15][16] In chelonians, 3 standard projections of a complete radiographic series include dorsoventral and laterolateral and craniocaudal projections. It is important to optimize the yield of radiographic examinations by allowing for maximal pulmonary inflation, which can aid in the diagnosis of pathological changes in the lungs.…”

Tomografia computadorizada do tórax de cadelas portadoras de neoplasias malignas: II - Avaliação dos campos pulmonares

“…Observou-se com grande freqüência a presença de quadro alveolar (Figura 1) identificado como atelectasia e/ou estase (60% dos animais -Quadro 1) e atribuiu-se à ocorrência desse fato à realização do exame sob anestesia geral com utilização de oxigênio a 100%, como fluxo diluente 33,34,35 , e ao tempo de duração do exame com o animal permanecendo sobre o mesmo decúbito 3,21,43 . A presença dessas densificações, visibilizadas em regiões ventrais dos lobos pulmonares, visto que o exame foi realizado em decúbito ventral, podem causar prejuízos na avaliação do parênquima …”