The effect of respiration and body position on terminal thoracic duct diameter and the lymphovenous junction: An exploratory ultrasound study

Sonography for assessment of thoracic duct anatomy and physiology before and after meals

The interest in clinical anatomy of the thoracic duct (TD) has recently grown, owing to discoveries linking its morphology to pathologies such as heart failure or liver cirrhosis. In the light of this knowledge, a cost-efficient and reliable in-vivo imaging method of TD should be devised. Ultrasonography satisfies these criteria and hence is a promising tool for assessment of TD's anatomy and function. Thirty-one healthy volunteers attended the examination after 6 h of fasting and 2 h without drink. Ultrasound of the left supraclavicular fossa was performed in search of TD's orifice into the venous angle. In each case, the largest diameter, number of orifices, presence of valves, tributaries, and motility of the TD were examined. We performed examinations in three sessions: after fasting, after standardized meal and 1 h after the meal. The statistical significance has varied among the three sessions. The strongest connection was shown in the third examination. The TD was visualized in 31 cases, 35 orifices were found, most of which drained into the venous angle. Multiple orifices were seen in four cases and valves in 15 cases. Tributaries were present in 17 cases. Mean widest and orifice diameter measured 3.23 and 2.0 mm, respectively. Spontaneous peristaltic-like movements of the TD were observed in 25 cases. We demonstrated that ultrasound is useful for assessment of TD's anatomy, allowing to visualize and quantify its key features. Moreover, our study is presumably the first to capture and describe TD's motility in vivo.

The cisterna chyli: a systematic review of definition, prevalence, and anatomy

The cisterna chyli is a lymphatic structure found at the caudal end of the thoracic duct that receives lymph draining from the abdominal and pelvic viscera and lower limbs. In addition to being an important landmark in retroperitoneal surgery, it is the key gateway for interventional radiology procedures targeting the thoracic duct. A detailed understanding of its anatomy is required to facilitate more accurate intervention, but an exhaustive summary is lacking. A systematic review was conducted, and 49 published human studies met the inclusion criteria. Studies included both healthy volunteers and patients and were not restricted by language or date. The detectability of the cisterna chyli is highly variable, ranging from 1.7 to 98%, depending on the study method and criteria used. Its anatomy is variable in terms of location (vertebral level of T10 to L3), size (ranging 2-32 mm in maximum diameter and 13-80 mm in maximum length), morphology, and tributaries. The size of the cisterna chyli increases in some disease states, though its utility as a marker of disease is uncertain. The anatomy of the cisterna chyli is highly variable, and it appears to increase in size in some disease states. The lack of well-defined criteria for the structure and the wide variation in reported detection rates prevent accurate estimation of its natural prevalence in humans.