How ultrasound and CT scans compare for trauma in dogs and cats

Abstract

OBJECTIVE: To determine the agreement between focused assessment with sonography for trauma (FAST) exams and computed tomography (CT) for the detection of pleural and peritoneal fluid and pneumothorax in animals that have sustained recent trauma. DESIGN: Prospective study. SETTING: University Teaching Hospital. ANIMALS: Thirteen dogs and 2 cats were enrolled into the study, with 10 having sustained blunt force trauma and 5 penetrating trauma. INTERVENTIONS: Abdominal FAST (AFAST) and thoracic FAST (TFAST) exams were performed by emergency room (ER) clinician or house officers and radiology house officers (radiology). TFAST evaluated for the presence of pneumothorax and pleural effusion, and AFAST evaluated for the presence of peritoneal effusion. A minimally sedated, full-body CT exam was performed on each patient and interpreted by a board-certified radiologist. The exams were performed in the same order for all patients: ER FAST, followed by radiology FAST, followed by CT, and operators were blinded to the results of the other exams. A kappa statistic was calculated to assess for agreement between the FAST exams and CT. MEASUREMENTS AND MAIN RESULTS: The median time to perform all 3 exams was 55 minutes (range 30-150 min). There was moderate to excellent agreement between AFAST and CT for detection of free peritoneal fluid (ER K = 0.82; radiology K = 0.53), fair to moderate agreement between TFAST and CT for detection of pleural free fluid (ER K = 0.53; radiology K = 0.36), and poor agreement between TFAST and CT for detection of pneumothorax (ER K = -0.06; radiology K = -0.12). CONCLUSIONS: FAST exams reliably identify the presence of free fluid in the peritoneal and pleural cavities; however, TFAST is not a reliable method to diagnose pneumothorax in dogs and cats following trauma.