Ventilator-Assisted Inspiratory and Expiratory Breath-Hold Thoracic Computed Tomographic Scans Can Detect Dynamic and Static Airway Collapse in Dogs with Limited Agreement with Tracheobronchoscopy

Abstract

Airway collapse (AC) in dogs includes a tracheal collapse, mainstem and lobar bronchial collapse, and bronchomalacia (i.e., segmental/subsegmental bronchial collapse). The clinical presentation of AC may overlap with non-collapsible airway disease (NCAD) or another non-lower airway respiratory disease (NLARD). This study determined whether paired inspiratory (I)/expiratory (E)-breath-hold computed tomography (I/E-BH CT) can detect a static and dynamic AC in dogs with spontaneous respiratory disease and it compared the CT-derived metrics of the AC to the tracheobronchoscopy metrics. The CT-acquired I and E diameter and cross-sectional area (CSA) for the trachea, mainstem and lobar bronchi in dogs with an AC (n = 16), NCAD (16), and NLARD (19) served for a dynamic percent of the airway narrowing (%AN) calculation. A scoring system assessed the bronchomalacia. The circularity was calculated for each airway. The results were compared to the tracheobronchoscopy collapse grading. In the dogs with an AC, the %AN was larger for the trachea, right mainstem bronchus and right middle lobar bronchus when they were compared to the dogs with NCAD and NLARD. Flattening was only identified for the trachea of the AC dogs. The agreement between the CT and tracheobronchoscopy scores was 20% from trachea to the lobar bronchi and 47% for the segmental/subsegmental bronchi. Paired I/E-BH CT can detect static and dynamic AC with limited agreement with the tracheobronchoscopy metrics. Independent scoring systems that are tailored to the clinical manifestations of functional impairments are needed.

Bronchial collapse and bronchial stenting in 9 dogs

“…A diagnosis of lower airway collapse typically is based on bronchoscopy 1‐4,6 . Computed tomography frequently is recommended in dogs, particularly with the addition of paired inspiratory and expiratory breath‐holding scans, to assist with diagnosis, and definition of location and grade 6,38,39 . The use of CT to assist with diagnosing dynamic airway collapse in humans appears to be increasing 40,41 .…”

“…[1][2][3][4]6 Computed tomography frequently is recommended in dogs, particularly with the addition of paired inspiratory and expiratory breath-holding scans, to assist with diagnosis, and definition of location and grade. 6,38,39 The use of CT to assist with diagnosing dynamic airway collapse in humans appears to be increasing. The main limitation of our study was its retrospective design.…”

“…mainstem and lobar bronchi, and only moderate agreement for bronchomalacia. A kappa coefficient value consistent with substantial agreement was not found for any location, and the authors concluded that although inspiratory and expiratory CT scans can detect airway collapse with limited agreement with tracheobronchoscopy, additional studies correlating the severity of airway collapse with FIGs are needed 39. …”

Prospective evaluation of the efficacy of inhaled steroids administered via the AeroDawg spacing chamber in management of dogs with chronic cough

“… 1 , 2 , 3 Computed tomography can also be used to document AWC but general anesthesia is required to obtain inspiratory and expiratory scans. 4 Bronchoscopy and bronchoalveolar lavage (BAL) cytology and culture are required for diagnosis of inflammatory airway diseases (IAD), such as CB and ELD. 1 , 5 Despite a plethora of treatments, steroids are considered the mainstay.…”

“…Airway collapse can sometimes be visualized on plain radiography but fluoroscopy and bronchoscopy increase sensitivity and specificity 1‐3 . Computed tomography can also be used to document AWC but general anesthesia is required to obtain inspiratory and expiratory scans 4 . Bronchoscopy and bronchoalveolar lavage (BAL) cytology and culture are required for diagnosis of inflammatory airway diseases (IAD), such as CB and ELD 1,5 .…”