Radiografia simples e compressiva na avaliação da traqueia em cães de pequeno porte

Abstract

Although tracheal illnesses feature high incidence rates among small-breed dogs, conventional diagnostic techniques based on radiographic examination frequently fail to detect such illnesses, due to the dynamic behavior of the animal’s tracheal lumen and to the static nature of the examination itself. Therefore, the purpose of this study is to initially assess the behavior of the tracheal lumen while being subjected to varying degrees of external pressure (i.e., compression-driven examinations involving lateral cervical thoracic radiographs at 5, 10, 15, and 20mmHg pressure levels), and to further compare the resulting analytical data against screenings achieved via conventional (simple) radiographic techniques. A total of 50 small-breed dogs were subjected to a five-step cervical thoracic radiographic routine which included five RX screenings (one for pressure-free imagery, and four for pressure-driven imagery at the aforementioned pressure levels). Two individuals failed to complete the study and were excluded from it, so a total of 48 dogs were finally assessed. Of those 48 individuals, 25 were diagnosed as suffering from total obstruction of the tracheal lumen (lumen collapse) at a certain point of the radiographic progression (CC Group), ranging from those displaying collapse at the lowest level of pressure (5 mmHg) (n=14) to those reaching collapsing levels at the highest level of pressure (20mmHg) (n=25). The other 23 individuals showed no signs of tracheal lumen collapse (CN Group). Individuals that according to radiographic analysis suffered from tracheal collapse (CC Group) also displayed coughing as a concurrent clinical sign whenever the pressure exerted by the cervical collar rose to 20mmHg. Likewise, in all radiographic screenings included in the evaluation, the trachea’s internal diameter in both, the area between the fourth and fifth cervical vertebrae (D4) and the thoracic inlet (DET), was smaller among individuals from the CC-Group than among those from the CN-Group. Also, within the CC Group, compression-based tracheal diameter measurements were smaller than simple radiographic figures. Hence, the outcomes from this study suggest that the compression technique can and should be applied as part of the tracheal radiographic assessment, while its accuracy rates exceed those of simple radiographic examinations. The effective application of the compression radiographic technique – especially at the 20mmHg pressure level, where radiographic data is concurrent with clinical signs of tracheal collapse – promotes the detection of tracheal disorders and lowers the incidence of D4 and DET variables in dogs suffering from tracheal weaknesses (CC Group).