Computed Tomography of Nonanesthetized Cats With Upper Airway Obstruction

Abstract

Upper airway obstruction is a potentially life-threatening problem in cats and for which a noninvasive, sensitive method rapid diagnosis is needed. The purposes of this prospective study were to describe a computed tomography (CT) technique for nonanesthetized cats with upper airway obstruction, CT characteristics of obstructive diseases, and comparisons between CT findings and findings from other diagnostic tests. Ten cats with clinical signs of upper airway obstruction were recruited for the study. Four cats with no clinical signs of upper airway obstruction were recruited as controls. All cats underwent computed tomography imaging without sedation or anesthesia, using a 16-slice helical CT scanner and a previously described transparent positional device. Three-dimensional (3D) internal volume rendering was performed on all CT image sets and 3D external volume rendering was also performed on cats with evidence of mass lesions. Confirmation of upper airway obstruction was based on visual laryngeal examination, endoscopy, fine-needle aspirate, biopsy, or necropsy. Seven cats were diagnosed with intramural upper airway masses, two with laryngotracheitis, and one with laryngeal paralysis. The CT and 3D volume-rendered images identified lesions consistent with upper airway disease in all cats. In cats with mass lesions, CT accurately identified the mass and location. Findings from this study supported the use of CT imaging as an effective technique for diagnosing upper airway obstruction in nonanesthetized cats.

Comparison of Thoracic Radiography and Computed Tomography in Calves with Naturally Occurring Respiratory Disease

“…This is consistent with reports in small animals describing the use of MDCT in awake or sedated animal for the acquisition of pelvic CTs for trauma evaluation in dogs, the abdomen in dogs with acute abdominal signs, and studies of the cat respiratory tract for assessment of upper airway obstruction (11–13, 15). Although calves with respiratory disease commonly have tachypnea and cough as well as other signs of respiratory compromise, the plane of sedation provided by the sedation protocol described herein allowed acquisition of CT images with a generally mild degree of respiratory motion, which did not preclude evaluation of the bronchial tree or pulmonary vasculature or parenchyma.…”

“…However, calves with severe respiratory impairment due to pneumonia often have an increased anesthetic risk. Although CT scanning protocols have been described for awake and sedated patients including for normal cats and cats with upper airway obstruction and intrathoracic disease, dogs with acute abdominal signs, and dogs with traumatic pelvic fractures, as well as healthy sedated foals neither has been evaluated in calves to date (11–15). …”

Thoracic high resolution CT using the modified VetMousetrap™ device is a feasible method for diagnosing canine idiopathic pulmonary fibrosis in awake West Highland White Terriers

“…In human pediatric radiology, high resolution CT scanning is often performed without general anesthesia . In previous studies where VetMousetrap™ device has been used to scan awake or mildly sedated animals, image quality has been adequate for diagnosis of airway diseases including dogs with primary laryngeal and tracheal airway obstruction, pulmonary thromboembolism, cats with upper airway obstruction and allergic asthma, and dogs with abdominal diseases and traumatic pelvic fractures . Motion artifact has been considered absent or mild in majority of examinations, as was the case also in our study.…”

Repair of a sliding (type I) hiatal hernia in a cat via herniorrhaphy, esophagoplasty and floppy Nissen fundoplication

“…Although not a traditional approach, CT was instrumental in a rapid diagnosis for both the cause of the upper airway obstruction and the displaced gastric anatomy through the hiatus. 14 Abdominal ultrasonography demonstrated gastric dilation and functionally reduced gastric motility, while ruling out other causes of persistent regurgitation in young cats (such as pyloric stenosis). Endoscopy confirmed the presence of esophagitis, gastritis and gastric flaccidity, and also prescreened the patient for the presence of contraindicated disease for the employment of the modified Nissen fundoplication technique.…”