Direct mesenteric lymphangiography has been recommended as the imaging technique of choice for use before and after thoracic duct occlusion performed to treat chylothorax in dogs and cats.1–3 Before ligation, lymphangiography allows radiographic localization and characterization of thoracic duct lesions and simplifies ligation by outlining the anatomic features of the duct and its branches.1,2 After ligation, lymphangiography allows radiographic confirmation that all branches of the thoracic duct have been successfully ligated.1,2 Disadvantages of performing direct mesenteric lymphangiography as described by Kagan and Breznock4 include that an invasive abdominal procedure, usually a paracostal laparotomy, must be performed to allow catheterization of a mesenteric lymph vessel1; the diagnostic procedure lengthens the anesthetic period associated with thoracic duct ligation by approximately 1 hour5; and mesenteric lymphatic catheterization can be difficult, especially in physically small dogs and in cats.3 However, direct mesenteric lymphangiography is preferred over direct peripheral (pedal) lymphangiography6–9 or inguinal lymphangiography10 because of the difficulty associated with identification, catheterization, and injection of small peripheral vessels. With this in mind, the ideal technique for lymphangiography would be minimally invasive and easy to perform and the duration of anesthesia would be minimal.
The purposes of the study reported here were to determine whether injection of a mesenteric lymph node with iodinated aqueous contrast medium results in radiographic delineation of the thoracic duct and its branches, ascertain the ideal interval between injection and radiographic imaging, and evaluate mesenteric lymphadenography performed via laparoscopic and surgical approaches in dogs. Our hypothesis was that direct injection of iodinated aqueous contrast medium into a mesenteric lymph node would result in adequate delineation of the thoracic duct and offer a simple and rapid alternative to mesenteric lymphangiography. We also hypothesized that mesenteric lymph node injection could be performed by use of a laparoscopic technique, precluding the need for an invasive abdominal surgical procedure.
Atravet, Ayerst Laboratories, Montreal, QC, Canada.
Numorphan, DuPont Pharma Inc, Mississauga, ON, Canada.
Vetalar, Vetrepharm Canada Inc, Belleville, ON, Canada.
Diazepam, SABEX Inc, Boucherville, QC, Canada.
Plasma-Lyte A, Baxter Corp, Toronto, ON, Canada.
Hypaque-M 76%, Nycomed Imaging AS, Picker International Canada Inc, Brampton, ON, Canada.
Euthansol, Schering-Plough Animal Health, Pointe-Claire, QC, Canada.
BD Spinal needle, BD Medical Systems, Franklin Lakes, NJ.
Methylene blue, SABEX Inc, Boucherville, QC, Canada.
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Enwiller TMRadlinsky MGMason DE, et al.Popliteal and mesenteric lymph node injection with methylene blue for coloration of the thoracic duct in dogs. Vet Surg 2003; 32: 359–364.