Comparison of Fluoroscopy and Computed Tomography for Tracheal Lumen Diameter Measurement and Determination of Intraluminal Stent Size in Healthy Dogs

Abstract

Tracheal collapse is a progressive airway disease that can ultimately result in complete airway obstruction. Intraluminal tracheal stents are a minimally invasive and viable treatment for tracheal collapse once the disease becomes refractory to medical management. Intraluminal stent size is chosen based on the maximum measured tracheal diameter during maximum inflation. The purpose of this prospective, cross-sectional study was to compare tracheal lumen diameter measurements and subsequent selected stent size using both fluoroscopy and CT and to evaluate inter- and intraobserver variability of the measurements. Seventeen healthy Beagles were anesthetized and imaged with fluoroscopy and CT with positive pressure ventilation to 20 cm H2O. Fluoroscopic and CT maximum tracheal diameters were measured by 3 readers. Three individual measurements were made at 8 pre-determined tracheal sites for dorsoventral (height) and laterolateral (width) dimensions. Tracheal diameters and stent sizes (based on the maximum tracheal diameter + 10%) were analyzed using a linear mixed model. CT tracheal lumen diameters were larger compared to fluoroscopy at all locations. When comparing modalities, fluoroscopic and CT stent sizes were statistically different. Greater overall variation in tracheal diameter measurement (height or width) existed for fluoroscopy compared to CT, both within and among observers. The greater tracheal diameter and lower measurement variability supported the use of CT for appropriate stent selection to minimize complications in veterinary patients.

Use of computational fluid dynamics to compare upper airway pressures and airflow resistance in brachycephalic, mesocephalic, and dolichocephalic dogs

“…CT and three-dimensional 82 (3D) internal rendering can accurately indicate the presence and sometimes the cause of upper airway obstruction in dogs (Stadler et al, 2011). It is the imaging modality of choice for stent selection in dogs with tracheal collapse (Williams et al, 2016).…”

Application of Micro‑Tech stents in malignant carinal stenosis

“…Prior to stent placement, patients underwent examinations including electrocardiograms and blood tests including routine blood counts, coagulation tests, liver and kidney function tests and electrolyte levels. Computed tomography scans of the chest, including coronal and sagittal reconstruction, and bronchoscopy were performed to assess the extent, type and degree of stenosis, which provided a reliable basis for stent selection and size customization (10,11). Preoperative and preanesthetic evaluations were conducted by interventional pulmonologists and anesthetists, respectively.…”

Stents in Veterinary Medicine

“…An inadequate stent size promotes stent migration and fracture [ 4 ]. The best method to assess the size of the tracheal lumen seems to be CT scans, but this method is often too expensive for pet owners [ 62 ]. Therefore, most measurements are based on radiographs from the dorso-abdominal and/or lateral position [ 63 ].…”