Comparison between sedation and general anesthesia for high resolution computed tomographic characterization of canine idiopathic pulmonary fibrosis in west highland white terriers

Canine idiopathic pulmonary fibrosis (CIPF) is a progressive interstitial lung disease mainly affecting West Highland white terriers (WHWTs). Thoracic high-resolution computed tomographic (T-HRCT) findings for CIPF acquired under general anesthesia have been described previously. However, the use of general anesthesia may be contraindicated for some affected dogs. Sedation may allow improved speed and safety, but it is unknown whether sedation would yield similar results in identification and grading of CIPF lesions. The aim of this prospective, observational, method-comparison, case-control study was to compare findings from T-HRCT images acquired under sedation versus general anesthesia for WHWTs affected with CIPF (n=11) and age-matched controls (n=9), using the glossary of terms of the Fleischner Society and a scoring system. Ground-glass opacity (GGO) was identified in all affected WHWTs for both sedation and general anesthesia acquisitions, although the GGO extent varied significantly between the two acquisitions (P<0.001). Ground-glass opacity was the sole lesion observed in control dogs (n=6), but was less extensive compared with affected WHWTs. Identification and grading of a mosaic attenuation pattern differed significantly between acquisitions (P<0.001). Identification of lesions such as consolidations, nodules, parenchymal and subpleural bands, bronchial wall thickening, and bronchiectasis did not differ between acquisitions. The present study demonstrated that T-HRCT obtained under sedation may provide different information than T-HRCT obtained under general anesthesia for identification and grading of some CIPF lesions, but not all of them. These differences should be taken into consideration when general anesthesia is contraindicated and sedation is necessary for evaluating WHWTs with CIPF.