Objective To investigate the depiction rate of normal cisterna chyli and thoracic duct by nonenhanced MR lymphography and to describe their appearances on MR imaging. Methods Special MR hydrography sequence was added to the MR imaging protocols of 112 patients undergoing MR examination of the thorax and upper abdomen. MR imaging sequences included: ①Respiratory-gated HASTE T2W sequence; ②Breath-hold FLASH T1W sequence; ③Respiratory-gated TSE 3D T2W sequence (3D MR hydrography sequence) in coronal plane. One hundred cases who met the inclusion criteria were included into the study for observation of the depiction rate, location and morphology of cisterna chyli and thoracic duct. Results On TSE 3D T2W imaging： ①Cisterna chyli was visualized in 71/100 (depiction rate 71.0%), morphologically including single-tube type 43.7% (31/71), bifurcation type (2-3 tubes) 23.9% (17/71), plexus type 32.4% (23/71). Average length of the cisterna chyli was 4.5 cm. ②The depiction rate of the lower segment of thoracic duct was 57.0% (57/100), average ductal diameter was 0.23 cm. ③The depiction rate of upper segment of the thoracic duct was 31.0% (31/100). Conclusion As a noninvasive method for depicting the lymphatic system, nonenhaced MR lymphography (TSE 3D T2W sequence) demonstrated a high depiction rate for cisterna chyli and lower thoracic duct. Combined with axial images of HASTE and FLASH sequences, the location and morphology of these larger lymphatic ducts can be defined.
Thoracic duct is the largest lymphatic vessel in the body. It originates from the chyle pool in the abdominal cavity, upward across aortic hiatus of the diaphragm into the right thoracic cavity, and finally importing into the left jugular vein angle. Thoracic duct plays a very important role in the transporting process of the body's lymph and chylous fluid. More than 70% of the lymph and chylous fluid transport through it into the blood. If the thoracic duct was damaged, it would lead to fluid and electrolyte imbalance, immune dysfunction, malnutrition and the patient's life would be endangered when it was serious. Therefore, the clinical significance of the thoracic duct is always a hot research issue. Through unremitting exploration in recent years, we have a further understanding about structure and function of the thoracic duct. And we used this to remould and ligate it to cure some intractable disease. Now we summarize the research progress as follows.
ObjectivesTo compare the clinical efficacy of different surgical thoracic duct management on prevention of postoperative chylothorax and its impact on the outcome of the patients. MethodsWe searched the electronic databases including PubMed, The Cochrane Library (Issue 4, 2016), Web of Science, CBM, CNKI, VIP and WanFang Data to collect randomized controlled trials (RCTs), cohort studies and case-control studies related to the comparison of different surgical thoracic duct management during esophagectomy on prevention of postoperative chylothorax from inception to May 2016. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then RevMan 5.2 software was used for meta-analysis. ResultsTwenty-three trials were included, involving four RCTs, four cohort studies and 15 case-control studies. The results of meta-analysis indicated:(1) Prophylactic thoracic duct ligation group had lower incidence of postoperative chylothorax compared with non thoracoic duct ligation group (RCT:OR=0.20, 95%CI 0.09 to 0.47, P=0.000 02; Co/CC:OR=0.20, 95%CI 0.14 to 0.28, P<0.000 01); (2) There were no significant differences between the two groups in the respect of mortality, morbidity and the 2-year, 3-year, 5-year survival rates (all P values >0.05); (3) Prophylactic thoracic duct ligation could reduce the reoperation rate of chylothorax complicating esophageal cancer patients (RCT:OR=0.17, 95%CI 0.10 to 0.28, P<0.000 01; Co/CC:OR=0.18, 95%CI to 0.11 to 0.32, P<0.000 01), and increase the cure rate of expectant treatment on them (OR=0.25, 95%CI 0.11 to 0.56, P=0.000 8); (4) En bloc thoracic duct ligation group had a lower incidence of postoperative chylothorax compared with single thoracic duct ligation group (OR=3.67, 95%CI 1.43 to 9.43, P=0.007). ConclusionProphylactic thoracic duct ligation during esophagectomy could effectively reduce the incidence of postoperative chylothorax and is good for reducing the reoperation rate of chylothorax complicating esophageal cancer patients. En bloc thoracic duct ligation has a better efficacy on prevention of postoperative chylothorax compared with single thoracic duct ligation.