Bronchography is a well established diagnostic radiographic procedure indispensable in the modern practice of medicine. The contrast media employed are numerous with new agents constantly being produced. This report deals with the recently introduced Hytrast.2 It is an aqueous contrast medium with many excellent properties, but is inclined to stimulate an undesirable tissue reaction; namely, a bronchographically induced crystalline-inclusion pneumonia. Contrast study of the bronchial tree was first reported by Chevalier Jackson in 1918, who utilized insufflation of dry powdered bismuth subcarbonate through a bronchoscope. Later, liquid media were introduced, first in oily and later in aqueous suspension. For the most part the contrast agents have been iodinated organic compounds. These, as well as the type of oil or aqueous suspension agents have been undergoing constant changes. The history of bronchography has been recorded in numerous publications (1–4, 12, 14, 21, 22). An ideal bronchographic contrast medium should have the following properties: (a) high radiopacity and contrast; (b) good flow properties so that the walls of the bronchi may be coated quickly and uniformly; (c) sufficient viscosity to adhere to the bronchial walls, remaining where originally instilled and not freely disseminating through the alveolar system; (d) prompt and complete elimination from the lungs after bronchography without further delayed migration; (e) physiologic innocuity and pharmacologic inertness—iodine, if used, is to be firmly bound so that it is not liberated in the body. No bronchographic medium at present, including Hytrast, satisfies all these criteria. Why Hytrast, in spite of its advantages, does not fulfill all these criteria is the subject of this report. Materials The contrast medium under investigation, Hytrast, is an aqueous suspension mixture of N-(2,3-dihydroxypropyl)-3,5diiodopyridone-4 and 3,5-diiodopyridone-4, containing 50 per cent w/v of combined iodine, sp. gr. 1.483 and pB. 7.1. The earlier preparation used in this work contained 1 per cent sodium carboxymethylcellulose yielding a viscosity of 3 to 6 poises, whereas the later preparation (Hytrast-19) contained 0.5 per cent sodium carboxymethylcellulose with a viscosity of 2.4 to 2.8 poises and with a suspended particle size of approximately 2–5 microns. Comparative experiments of Hytrast with Dionosil Aqueous and Dionosil Oily were carried out. Some of the relative characteristics of these three preparations are shown in Table I. In addition, one comparative experiment was made with Hytrast and Lipiodol. The experimental animals used in this work were 18 unselected mongrel dogs. These animals were chosen because their tracheal and bronchial calibers are quite similar to those of man.
No takes yet. Share an insight, caveat, or question.
Rayl et al. (1963) studied this question.