Radiographic evaluation of tracheal collapse in dogs by compressive technique / Avaliação radiográfica do colapso de traqueia em cães pela técnica compressiva

The purpose of this study was to verify the applicability of the compressive radiographic technique (pressures of 5, 10, 15 and 20mmHg) in the diagnosis of tracheal collapse in small breed dogs, in lateral cervicothoracic radiography. Out of the 50 dogs evaluated, 25 presented tracheal collapse (TG group), 23 did not present tracheal collapse (CG) and two were excluded because they did not tolerate a pressure of 20 mmHg. The TG group presented a smaller internal diameter of the trachea in the region of the fourth cervical vertebra (D4) and at the entrance of the thorax (TDE) compared to the CG group, in all the radiographic projections performed, as well as within the TG group where the compressive technique differed from conventional. Furthermore, there was a correlation between the clinical sign of coughing during cervical collar use and the presence of radiographic tracheal collapse at a pressure of 20 mmHg. It was concluded that the compressive radiographic technique was feasible and efficient in confirming the diagnosis of tracheal collapse in dogs, especially in the pressure of 20 mmHg, where it was associated with clinical signs, and can be used in isolation or complementary to the conventional technique.(AU)

O objetivo deste trabalho foi verificar a aplicabilidade da técnica radiográfica compressiva no diagnóstico do colapso de traqueia em cães de raças pequenas, por meio da comparação do diâmetro da traqueia durante a radiografia cervicotorácica lateral convencional e sobre influência da compressão externa com pressões de 5, 10, 15 e 20mmHg (técnica compressiva). Dos 50 cães avaliados, 25 apresentaram colapso de traqueia (grupo TG), 23 não apresentaram o colabamento traqueal (grupo controle - CG) e dois foram excluídos por não tolerarem a pressão de 20mmHg. Os diâmetros internos da traqueia na região da quarta vértebra cervical (D4) e na entrada do tórax (DET) foram menores no grupo TG em relação ao CG, em todas as projeções radiográficas realizadas, bem como dentro do grupo TG, no qual a técnica compressiva diferiu da convencional. Houve correlação entre o sinal clínico de tosse durante o uso de coleira cervical e a presença do colapso de traqueia radiográfico, na pressão de 20mmHg. Concluiu-se que a técnica radiográfica compressiva foi exequível e eficiente na confirmação do diagnóstico do colapso de traqueia em cães, especialmente na pressão de 20mmHg, em que houve associação com sinais clínicos, podendo ser utilizada de forma isolada ou complementar à técnica convencional.(AU)

Fluoroscopic characteristics of tracheal collapse and cervical lung herniation in dogs: 222 cases (2012–2015)

This retrospective study included 222 dogs suspected to have tracheal collapse (TC) and examined between 1 January 2012 and 31 December 2015. Fluoroscopic and radiographic images and medical records were evaluated to investigate the fluoroscopic characteristics of TC and cervical lung herniation (CLH), and to determine their relationships to various influencing. Grade of TC, existence of tracheal kinking, location of CLH (right or left side), and grade of CLH were evaluated fluoroscopically. One hundred ninety-nine dogs (89.6%) were diagnosed with TC. Presence of TC was not associated with the patients' cough history; however, CLH was positively correlated with cough history (odds ratio [OR], 2.896; 95% confidence interval [CI], 1.556 to 5.390) and was affected by tracheal kinking (OR, 3.841; 95% CI, 1.884 to 7.831). Chronic cough was not related with CLH. Since TC can be observed in patients without a history of cough, presence of TC should be ruled out by using physical examination and diagnostic imaging. Although CLH is associated with a history of cough, it is a common appearance in dogs, and transient coughing can elicit CLH in patients without a history of cough.

Ultrasonographic evaluation of tracheal collapse in dogs

Tracheal ultrasonography was performed to measure the width of the tracheal ring shadow and to assess the clinical relevance of these measurements for identifying tracheal collapse. The first tracheal ring width (FTRW) and thoracic inlet tracheal ring width (TITRW) were measured on both expiration and inspiration. The mean of the FTRW width (129 dogs) was greater in expiration (10.97 +/- 1.02 mm, p = 0.001) than that in inspiration (9.86 +/- 1.03 mm). For 51 normal dogs, the mean of the TITRW width was greater in expiration (9.05 +/- 1.52 mm, p = 0.001) than in inspiration (8.02 +/- 1.43 mm). For 78 tracheal collapse dogs, the mean of the TITRW width was greater in expiration (15.89 +/- 1.01 mm, p = 0.001) than in inspiration (14.85 +/- 1.17 mm). The TITRW/FTRW ratio of the normal dogs was higher (p = 0.001) in expiration (0.81 +/- 0.09) than that in inspiration (0.79 +/- 0.10). When compared between the normal and tracheal collapse dogs, the TITRW/FTRW ratio was also increased (p = 0.001) both in expiration (1.54 +/- 0.09) and inspiration (1.47 +/- 0.08), respectively. Based on these results, the cutoff level of the TITRW/FTRW ratio was statistically analyzed according to the receiver operating characteristic curve and it could be set at 1.16 in expiration and at 1.13 in inspiration. We have demonstrated that tracheal ultrasonography is a useful technique for the evaluation of tracheal collapse and it can be a supportive tool together with the radiographic findings for making the correct diagnosis.

The Safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs

To evaluate the potential utility of a self-expandable intratracheal nitinol stent with flared ends for the treatment of tracheal collapse in dogs, endotracheal stenting therapy was performed under fluoroscopic guidance in four dogs with severe tracheal collapse. During the 4 to 7 month followup, after stent implantation, clinical signs, including dyspnea and respiratory distress, dramatically improved in all dogs. The radiographs showed that the implanted stents improved the tracheal collapse, and there were no side effects such as collapse, shortening or migration of the stents. In conclusion, the self-expandable intratracheal nitinol stents provided adequate stability to the trachea and were effective for attenuating the clinical signs associated with severe tracheal collapse.