Anatomic and volumetric characterization of the cisterna chyli using CT lymphangiography and computer‐assisted design software in dogs with idiopathic chylothorax

Abstract

The objectives of this retrospective, observational study were to characterize the anatomical features of the cisterna chyli (CC) in a cohort of dogs diagnosed with idiopathic chylothorax that underwent CT lymphangiography (CTLa), and to evaluate the feasibility of computer-assisted design (CAD) software to quantify volumetric measurements of the CC. Twenty-three clientowned dogs with idiopathic chylothorax were included. Additionally, CTLa was performed in three canine cadavers to assess the ability of CAD software to accurately acquire volumetric measurements. Injection sites, attenuation values, anatomic location, dimensions, and aortic diameter to CC ratio (Ao:CC) were recorded. Video records of video-assisted thoracic surgery (VATS) thoracic duct ligation (TDL) were reviewed in eight out of 23 dogs to compare operative and CTLa findings.The CC was dorsal and right-sided in 18 out of 23 dogs, located between L1 and L4 in 21 dogs, and extended as far cranially as T11 in two dogs. The median measurements for length, height, and width were 150.0, 5.5, and 13.3 mm, respectively. Median total volume was 1.82 mL. Median volumes to the right and left of the aorta were 1.46 and 0.49 mL, respectively (P = .014). Median total CC volume to body weight ratio (CC:bw) was 0.07 mL/kg. The presence of an intrathoracic CC was observed intraoperatively in six out of eight cases that underwent VATS TDL. Findings supported the use of CTLa and CAD as feasible methods for characterizing the CC in dogs diagnosed with chylothorax. These methods may facilitate interventional planning involving the CC such as embolization.

Canine idiopathic chylothorax: Anatomic characterization of the pre‐ and postoperative thoracic duct using computed tomography lymphography

“…Our study suggests that the anatomical morphology of the thoracic duct in canines with chylothorax varies according to the individual. There might also be other thoracic ducts that are not apparent on preoperative lymphography because it is reported that thoracic ducts may form a network during embryonic periods 12,13 . We assume that some embryonic ducts may exist, which are fine, collapsed, and inadequate to contain lymphatic fluid.…”

“…These studies report that the canine thoracic duct is predominantly located on the right side of the thoracic cavity, although it can sometimes occur on the left side or be present with multiple branches. Recent studies using computed tomography lymphography (CTLG) have helped to better describe the thoracic duct anatomy in dogs 8,13 . In humans, thoracic ducts are bilateral in the embryonic period and then merge to form the thoracic duct on the left side of the body with branches 14 .…”

Resolution of chyloabdomen following the removal of a projectile causing a granuloma

“…Computed tomographic lymphangiography is currently considered the gold standard technique for evaluating the lymphatic system in human and veterinary medicine. (Cárdenas & Chopra, 2002 ; Esterline et al., 2005 ; Singh et al., 2011 and Carvajal et al., 2020 ). In our case, the intra‐metatarsal pad injection technique showed normal progression of contrast from the cisterna chyli to the beginning of the thoracic duct, but no further progression from this point was observed 15 min post‐injection.…”

Computed Tomography for Diagnosing Chylothorax Associated with Cranial Vena Cava Thrombosis in a Dog

“…Lymphangiography differentiates the rupture or congenital anomaly of the thoracic duct, which is the cause of chylothorax (2,36). Also, preoperative lymphangiography is recommended for appropriate surgical planning (8,13). CT lymphangiography can more accurately identify branches of the thoracic duct than the standard radiographic lymphangiography (13,34).…”