Author(s): Ballegeer EA, Adams WM, Dubielzig RR, Paoloni MC, Klauer JM, Keuler NS. Computed tomography characteristics of canine tracheobronchial lymph node metastasis. Vet Radiol Ultrasound. 2010 Jul-Aug;51(4):397-403. PMID 20806871
Journal: Veterinary Radiology & Ultrasound : The Official Journal Of The American College Of Veterinary Radiology And The International Veterinary Radiology Association, Volume 51, Issue 4,
Tracheobronchial lymph node evaluation is critical for accurate staging of canine thoracic neoplasia and is more accurately achieved with computed tomography (CT) than radiography. Thoracic CT scans of 18 canine patients with known tracheobronchial lymph node histopathology and 10 clinically normal dogs were compared to establish if enlargement or contrast enhancement pattern correlated with metastatic status. Absolute lymph node size and three anatomically normalized lymph node ratios were significantly correlated with metastasis or severe granulomatous lymphadenitis (P < 0.0003). Transverse maximum lymph node diameter of 12 mm or lymph node to thoracic body ratio of 1.05 are proposed cutoffs, above which metastatic involvement is very likely; however, only minimal accuracy was gained with normalized ratios. Lymph node contrast enhancement pattern was also significantly correlated to disease. A heterogenous and/or ring pattern was related to metastatic disease (P = 0.03). Recommended protocol for CT examination of the tracheobronchial lymph nodes is 1-1.5 mm slices and intervals, intravenous contrast, and control of respiratory motion.