METRIZAMIDE INSUFFLATION BRONCHOGRAPHY: A NEWDIAGNOSTIC APPROACH

Abstract

The search for a better and safer technique for roentgenographic opacification of the canine bronchial tree led to experimentation with metrizamide insufflation. Because metrizamide may be obtained in a microparticulate powdered form, it was postulated that oxygen pressure deliver through a powder blower connected to a selective bronchial catheter would produce a diagnostic quality bronchogram. Metrizamide was used because of its biologically inert, water soluble properties.The delivery system consisted of a DeVilbiss No. 175 Powder Blower attached to an oxygen clinder with pressure regulator. A soft polyethylene catheter with flexible wire guide was used for selective bronchial catheterization under fluoroscopic control. Oxygen pressure for delivery was kept below 20 pounds/in2, and oxygen flow was controlled by a footswitch.Insufflation was performed with the animal in ventrodorsal recumbency. Three to eight grams of metrizamide were selectively delivered to the left caudal, right caudal, and accessory lung lobes in 0.5‐to 1.0 second bursts over a period of 1–5 minutes.Powder deposition in subsegmental bronchi was adequate when the insufflation catheter was placed in primary bronchi. Cranial lobe bronchi could be opacified by gravity directed flow of contrast medium‐laden bronchial mucous. Alveolarization and radiographic clearing of me‐trizamide from the pulmonary field occurred within 30 to 60 minutes.No insufflation‐induced radiographic lesions were recognized. Gross necropsy did not reveal lesions associated with insufflation. Histopathologic examination showed mild multifocal lesions of pneumonitis.