Coil or Plug-Assisted Ethylene Vinyl Alcohol Copolymer (EVOH) Thoracic Duct Embolization in the Treatment of Postoperative Chylothorax.

Eleven patients (5 men, 6 women) with post-operative thoracic duct injuries and high output chylothorax were treated with thoracic duct embolization (TDE). Six patients underwent intraprocedural thoracic duct ligation at the time of original procedure. In all cases, the pleural fluid demonstrated high triglyceride levels (414 mg/dL; interquartile range [IQR], 345 mg/dL). Median daily (IQR) chest tube outputs before and after TDE were 900 mL (1,200 mL) and 325 mL (630 mL), respectively. Coil- or plug-assisted ethylene vinyl alcohol (EVOH) copolymer was used as embolic agent in all patients. Technical and clinical success rates were 100% and 82%, respectively. Nontarget venous embolization of EVOH copolymer was not identified on subsequent imaging.

Thoracic Duct Visualization in Esophageal Resection: A Pilot Trial.

INTRODUCTION: Inadvertent thoracic duct injury is common during esophagectomy and may result in postoperative chylothorax. This study's objective was to investigate utility of patent blue injection as a modality for intraoperative thoracic duct visualization. METHODS: A prospective, single-arm, interventional study of patients undergoing minimally invasive esophagectomy was performed. Patients were injected with patent blue dye into both groins prior to thoracic stage of surgery and assessed for duct visualization. Control group was formed by propensity score matching using retrospectively collected data regarding patients who underwent esophagectomy. RESULTS: A total of 25 patients were included in analysis, compared to a control of 50 patients after matching. Thoracic duct was visualized in 60% of patients in the study group (15/25 patients). Significant differences were found between study and control groups (p < 0.05) with regards to median operative time (422 vs. 285 min, respectively), overall complications (16 vs. 34%, respectively), and median postoperative length of stay (13.5 vs. 10 days, respectively). There was a difference in rate of chyle leak between study and control groups; however, this was not significant (0 vs. 12%, respectively, p = 0.17). CONCLUSION: Patent blue injection represents a simple method for thoracic duct visualization during minimally invasive esophagectomy which may improve surgical outcomes.

Ultrasound analysis of cervical thoracic duct for patients with constrictive pericarditis and chylothorax.

PURPOSE: To analyze ultrasound features of cervical thoracic duct for patients with constrictive pericarditis and chylothorax. METHODS: Patients were retrospectively assessed. The patients were divided into a non-pleural effusion (PE) group (n = 54), a chylothorax group (n = 23), and non-chylothorax group (n = 28). Conventional ultrasound was used to obtain the maximum inner diameter and collapse of the inferior vena cava, the inner diameter of left cervical thoracic duct, and the frequency of opening of the valve at the end of the left thoracic duct. Contrast ultrasonography was used to score the reverse flow of the thoracic tube. RESULTS: The percentage of PE was 48.5%, and the percentage of chylothorax was 21.9%. The three groups had significant differences in five parameters. The inner diameter of left cervical thoracic duct was correlated with the degree of central venous pressure. Contrast ultrasonography was effective in quantitative assessment of the degree of intravenous-thoracic cord reverse flow which correlated with all parameters of central venous pressure. CONCLUSION: Thoracic duct dilation and regurgitation secondary to central venous pressure can lead to chyloreflux disorder and may be the mechanism of chylothorax occurrence in constrictive pericarditis.

Dynamic Contrast-enhanced CT Lymphangiography to Quantify Thoracic Duct Lymphatic Flow.

Background CT lymphangiography has been used to image the lymphatic anatomy and assess lymphatic abnormalities. There is, however, a need to develop a method for quantification of lymphatic flow rate in the thoracic duct (TD). Purpose To develop and validate a TD lymphatic flow measurement technique using dynamic contrast-enhanced CT lymphangiography. Materials and Methods Lymphatic flow rate was measured with two techniques: a first-pass analysis technique based on a single compartment model and a thresholding technique distinguishing between opacified and nonopacified voxels within the TD. The measurements were validated in a swine animal model between November 2021 and September 2022. CT images were acquired at 100 kV and 200 mA using a fast-pitched helical scan mode covering the entire TD following contrast material injection into the bilateral inguinal lymph nodes. Two helical CT scans, acquired at the base and peak contrast enhancement of the TD, were used to measure lymphatic flow rate. A US flow probe surgically placed around the TD provided the reference standard measurement. CT lymphatic flow measurements were compared with the reference US flow probe measurements using regression and Bland-Altman analysis. Repeatability was determined using repeated flow measurements within approximately 10 minutes of each other. Results Eleven swine (10 male; mean weight, 43.6 kg ± 2.6 [SD]) were evaluated with 71 dynamic CT acquisitions. The lymphatic flow rates measured using the first-pass analysis and thresholding techniques were highly correlated with the reference US flow probe measurements (r = 0.99 and 0.91, respectively) and showed good agreement with the reference standard, with Bland-Altman analysis showing small mean differences of 0.04 and 0.05 mL/min, respectively. The first-pass analysis and thresholding techniques also showed good agreement for repeated flow measurements (r = 0.94 and 0.90, respectively), with small mean differences of 0.09 and 0.03 mL/min, respectively. Conclusion The first-pass analysis and thresholding techniques could be used to accurately and noninvasively quantify TD lymphatic flow using dynamic contrast-enhanced CT lymphangiography. © RSNA, 2023 See also the editorial by Choyke in this issue.

Transvenous retrograde thoracic duct embolization for effective treatment of recurrent plastic bronchitis after fontan palliation.

We report the case of a 5.5-year-old patient (16 kg/105 cm) who presented with plastic bronchitis (PB) refractory to conservative treatment 3 months after completion of Fontan palliation. Bi-inguinal transnodal fluoroscopy-guided lymphangiogram confirmed the chylous leak originating from the thoracic duct (TD) into the chest and did not opacify any central lymphatic vessel for direct transabdominal puncture. Retrograde transfemoral approach was adopted to catheterize the TD and selectively embolize its caudal portion using microcoils and liquid embolic adhesive. Recurrence of symptoms after 2 months indicated a redo catheterization to occlude the TD entirely using the same technique. The procedure was successful and the patient was discharged after 2 days with sustained clinical improvement at 24 months postoperative. In the context of refractory PB, end-to-end transvenous retrograde embolization of the TD appears to be an interesting alternative to more complex interventions such as transabdominal puncture, decompression, or surgical ligation of the TD.

Characterization and treatment of thoracic duct obstruction in patients with lymphatic flow disorders.

PURPOSE: The contribution of thoracic duct obstruction to lymphatic flow disorders has not been well-characterized. We describe imaging findings, interventions, and outcomes in patients with suspected duct obstruction by imaging or a lympho-venous pressure gradient (LVPG). MATERIALS AND METHODS: Clinical, imaging, and interventional data, including the LVPG, of patients with flow disorders and imaging features of duct obstruction who underwent lymphatic intervention were retrospectively reviewed, collated, and analyzed with descriptive statistics. RESULTS: Eleven patients were found to have obstruction, median age 10.4 years (interquartile range: 8-14.9 years). Pleural effusions were seen in 8/11 (72%), ascites in 8/11 (72%), both in 5/11 (45%), and protein-losing enteropathy in 5 (45%). Eight patients (72%) had congenital heart disease. The most common site of obstruction was at the duct outlet in 7/11 patients (64%). Obstruction was secondary to extrinsic compression or ligation 4 patients (36%). Nine patients (82%) underwent interventions, with balloon dilation in 7/9 (78%), massive lymphatic malformation drainage and sclerotherapy in 1, and lympho-venous anastomosis in 1. There was resolution of symptoms in 7/9 (78% who underwent intervention, with worsening in 1 patient and no change in 1. In these patients, preprocedure mean LVPG was 7.9 ± 5.7 mmHg and postprocedure gradient was 1.6 ± 1.9 mmHg (p = 0.014). Five patients in this series underwent intervention solely to alleviate duct obstruction and in 4/5 (80%) this led to resolution of symptoms (p = 0.05). CONCLUSION: Duct obstruction may be seen in lymphatic flow disorders and can occur from intrinsic and extrinsic causes. Stenosis at the outlet was most common. Obstruction can be demonstrated by an elevated LVPG, and interventions to alleviate the obstruction can be beneficial.

Factors Contributing to Successful Transvenous Retrograde Thoracic Duct Cannulation.

PURPOSE: To identify key factors for successful transvenous retrograde cannulation (TVRC) of the thoracic duct. MATERIALS AND METHODS: A total of 47 consecutive patients (62.1 ± 13.2 years; 32 men) who underwent attempted TVRC between July 2016 and July 2021 were included. Reasons for interventions were chylous leakage from the chest (n = 36), abdomen (n = 6), and other sites (n = 5). Patient age, sex, access vein (femoral vs brachial), anatomic classification (presence of dominant channel vs plexiform) of the terminal thoracic duct, and engagement of a diagnostic catheter into the jugulovenous junction were included in the analyses. Anatomic details were evaluated according to catheter-based high-pressure lymphangiography and conventional intranodal lymphangiography. The Firth bias-reduced penalized-likelihood logistic regression model was used to analyze prognostic factors. RESULTS: TVRC was successful in 33 of the 47 patients (70%). In univariate analysis, femoral access, diagnostic catheter engagement, and presence of dominant channel were significant positive prognostic factors (P <.05). In multivariate analysis, diagnostic catheter engagement and presence of dominant channel were significant prognostic factors (P <.05). Diagnostic catheter engagement showed the highest prognostic performance (accuracy = 0.872), followed by presence of a dominant channel. High-pressure catheter-based lymphangiographic findings showed better performance (accuracy, 0.844 vs 0.727) than intranodal lymphangiography to delineate the anatomy of the terminal thoracic duct. CONCLUSIONS: A secure selection of the jugulovenous junction and the presence of a dominant channel in the terminal portion of the thoracic duct were significant prognostic factors for successful TVRC.

Magnetic resonance three-dimensional steady-state free precession imaging of the thoracic duct in patients with Fontan circulation and its relationship to outcomes.

BACKGROUND: Lymphatic complications are common in patients with Fontan circulation. Three-dimensional balanced steady-state free precession (3D bSSFP) angiography by cardiovascular magnetic resonance (CMR) is widely used for cardiovascular anatomical assessment. We sought to determine the frequency of thoracic duct (TD) visualization using 3D bSSFP images and assess whether TD characteristics are associated with clinical outcomes. METHODS: This was a retrospective, single-center study of patients with Fontan circulation who underwent CMR. Frequency matching of age at CMR was used to construct a comparison group of patients with repaired tetralogy of Fallot (rTOF). TD characteristics included maximum diameter and a qualitative assessment of tortuosity. Clinical outcomes included protein-losing enteropathy (PLE), plastic bronchitis, listing for heart transplantation, and death. A composite outcome was defined as presence of any of these events. RESULTS: The study included 189 Fontan patients (median age 16.1 years, IQR 11.0-23.2 years) and 36 rTOF patients (median age 15.7 years, IQR 11.1-23.7 years). The TD diameter was larger (median 2.50 vs. 1.95 mm, p = 0.002) and more often well visualized (65% vs. 22%, p < 0.001) in Fontan patients vs. rTOF patients. TD dimension increased mildly with age in Fontan patients, R = 0.19, p = 0.01. In Fontan patients, the TD diameter was larger in those with PLE vs. without PLE (age-adjusted mean 4.11 vs. 2.72, p = 0.005), and was more tortuous in those with NYHA class ≥ II vs. class I (moderate or greater tortuosity 75% vs. 28.5%, p = 0.02). Larger TD diameter was associated with a lower ventricular ejection fraction that was independent of age (partial correlation = - 0.22, p = 0.02). More tortuous TDs had a higher end-systolic volume (mean 70.0 mL/m2 vs. 57.3 mL/m2, p = 0.03), lower creatinine (mean 0.61 mg/dL vs. 0.70 mg/dL, p = 0.04), and a higher absolute lymphocyte count (mean 1.80 K cells/µL vs. 0.76 K cells/µL, p = 0.003). The composite outcome was present in 6% of Fontan patients and was not associated with TD diameter (p = 0.50) or tortuosity (p = 0.09). CONCLUSIONS: The TD is well visualized in two-thirds of patients with Fontan circulation on 3D-bSSFP images. Larger TD diameter is associated with PLE and increased TD tortuosity is associated with an NYHA class ≥ II.

Impact of fluorescent thoracic duct lymphography via intranodal approach in minimal access esophageal cancer surgery.

PURPOSE: Chyle leak resulting from thoracic duct (TD) injury poses significant morbidity and mortality challenges. We assessed the feasibility of using near-infrared (NIR) indocyanine green (ICG) imaging for intraoperative fluorescence TD lymphography during minimal access esophagectomy (MAE) in a semiprone position with inguinal nodal injection of ICG dye. METHODS: Ninety-nine patients with esophageal or gastroesophageal junctional cancer undergoing MAE received inguinal node injections of 2.5 mg ICG dye (total 5 mg) under sonographic guidance during anesthesia induction. Stryker's 1688 AIM HD system was used in 76 cases, Karl Storz OPAL 1 S in 20, and in three cases the Karl Storz Rubina. RESULTS: In 93 patients (94%), the TD was clearly delineated along its entire length; it was not visualized in 6 patients (6%). Fluorescence guidance facilitated TD ligation in 16 cases, while 3 cases required clipping of duct tributaries for oncological considerations. Twenty-eight patients exhibited minor duct variations. Fluorescence was sustained throughout surgery (median observation time 60 min post-injection; range 30-330). No patient experienced any chyle leak within 30 days post-surgery and no adverse reactions to ICG was evident. CONCLUSIONS: Intraoperative fluorescence TD lymphography using ICG during MAE in a semiprone position with inguinal nodal injection proved safe, feasible, and effective, allowing clear visualization of the TD in almost all cases. This approach aids safe ligation and reduces chyle leak risk. It offers real-time imaging of TD anatomy and variations, providing valuable feedback to surgeons for managing TD injuries during MAE procedures and represents an excellent educational tool.

Near-infrared fluorescence imaging of thoracic duct in minimally invasive esophagectomy.

Chylothorax is a serious complication after esophagectomy and there are unmet needs for new intraoperative navigation tools to reduce its incidence. The aim of this study is to explore the feasibility and effectiveness of near-infrared fluorescence imaging (NIR-FI) with indocyanine green (ICG) to identify thoracic ducts (TDs) and chyle leakage during video-assisted thoracoscopic esophagectomy. We recruited 41 patients who underwent thoraco-laparoscopic minimally invasive esophagectomy (MIE) for esophageal cancer in this prospective, open-label, single-arm clinical trial. ICG was injected into the right inguinal region before operations, after which TD anatomy and potential chyle leakage were checked under the near-infrared fluorescence intraoperatively. In 38 of 41 patients (92.7%) using NIR-FI, TDs were visible in high contrast. The mean signal-to-background ratio (SBR) value of all fluorescent TDs was 3.05 ± 1.56. Fluorescence imaging of TDs could be detected 0.5 hours after ICG injection and last up to 3 hours with an acceptable SBR value. The optimal observation time window is from about 1 to 2 hours after ICG injection. Under the guidance of real-time NIR-FI, three patients were found to have chylous leakage and the selective TD ligations were performed intraoperatively. No patient had postoperative chylothorax. NIR-FI with ICG can provide highly sensitive and real-time assessment of TDs as well as determine the source of chyle leakage, which might help reduce TD injury and direct selective TD ligation. It could be a promising navigation tool to reduce the incidence of chylothorax after minimally invasive esophagectomy.

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.

Delayed non-selective contrast-enhanced CT can reveal spontaneous contrast enhancement of the lymphatic system in cats.

The authors incidentally observed that, on delayed postcontrast CT studies, feline patients could show increased attenuation of the lymphatic system. The aim of the present study was to evaluate if the lymphatic system of feline patients undergoing intravenous administration of contrast medium might consistently enhance on delayed postcontrast CT studies. Feline patients that underwent CT examination for variable diagnostic purposes were included in this multicentric observational descriptive study. A 10-min delayed postcontrast whole-body CT series was obtained for all cats enrolled and the following anatomic structures were systematically assessed: mesenteric lymphatic vessels, hepatic lymphatic vessels, cisterna chyli, thoracic duct, and anastomosis of the thoracic duct with the systemic venous system. A total of 47 cats were included in the study. The mesenteric lymphatic vessels showed enhancement in the selected series in 39 of 47 (83%) patients and the hepatic lymphatic vessels in 38 of 47 (81%) patients. The cisterna chyli, thoracic duct, and the point of anastomosis of the thoracic duct with the systemic venous circulation were enhanced in 43 (91%), 39 (83%), and 31 of 47 (66%) cats, respectively. This study confirms the initial observation. The mesenteric and hepatic lymphatic system, the cisterna chyli, the thoracic duct, and its anastomosis with the systemic venous circulation of feline patients undergoing intravenous administration of iodinated contrast medium can show spontaneous contrast enhancement in non-selective 10-min delayed contrast-enhanced CT series.

Therapeutic effect of lymphography in the postoperative chylothorax - case reports and literature review.

Postoperative chylothorax is a well-known rare complication of thoracic surgery. It is a serious complication that is fatal in cases of inadequate treatment. The authors present 2 cases of postoperative chylothorax that were successfully treated by performing pedal and/or intranodal lymphography. In one case, the patient underwent lymphography after previous unsuccessful surgical ligation of the thoracic duct. The presented case reports describe therapeutic importance of conventional lymphography as a minimally invasive treatment of the postoperative chylothorax.

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.

Thoracic duct embolization in treating postoperative chylothorax: does bail-out retrograde access improve outcomes?

OBJECTIVES: To evaluate clinical outcomes of thoracic duct embolization (TDE) for the management of postoperative chylothorax with the aid of the bail-out retrograde approach for thoracic duct cannulation (TDC). MATERIALS AND METHODS: Forty-five patients with postoperative chylothorax underwent Lipiodol lymphangiography (LLG) between February 2016 and November 2019. If targetable central lymphatic vessels were identified in LLG, TDC, a prerequisite for TDE, was attempted. While the conventional antegrade transabdominal approach was the standard TDC method, the retrograde approach was applied as a bail-out method. Embolization, the last step of TDE, was performed after confirming leakages in the trans-TDC catheter lymphangiography. Technical and clinical success rates were determined retrospectively. RESULTS: TDC was attempted in 40 among 45 patients based on LLG findings. The technical success rate of TDC with the conventional antegrade approach was 78% (31/40). In addition, six more patients were cannulated using the bail-out retrograde approach, which raised the technical success rate to 93% (37/40). While 35 patients underwent embolization (TDE group), ten patients did not (non-TDE group) for the following reasons: (1) lack of targetable lymphatics for TDC in LLG (n = 5), (2) technical failure of TDC (n = 3), and (3) lack of discernible leakages in the transcatheter lymphangiography (n = 2). The clinical success of the TDE group was 89% (31/35), compared with 50% (5/10) of the non-TDE group. One major procedure-related complication was bile peritonitis caused by the needle passage of the distended gallbladder. CONCLUSIONS: Bail-out retrograde approach for TDC could improve the overall technical success of TDC significantly. KEY POINTS: • Bail-out retrograde thoracic duct access may improve the overall technical success of thoracic duct access, thus improving the clinical success of thoracic duct embolization.

Pragmatic role of noncontrast magnetic resonance lymphangiography in postoperative chylothorax or cervical chylous leakage as a diagnostic and preprocedural planning tool.

OBJECTIVES: To define the roles of noncontrast magnetic resonance lymphangiography (MRL) in the management of postoperative chylothorax or cervical chylous leakage. METHODS: A total of 50 consecutive patients underwent noncontrast MRL, intranodal lymphangiography, and thoracic duct embolization between May 2016 and April 2020. Their mean age was 62.6 years ± 10.3 (SD) years, and 35 of the participants were men. Conventional lymphangiographic images were sufficient in quality as a reference for the evaluation of diagnostic accuracy of leakage and location in 35 patients (70%) and for evaluation of anatomic details of the thoracic duct and jugulovenous junction in 34 patients (68%). RESULTS: MRL showed that the sensitivity, specificity, and positive and negative predictive values for leakage detection were 100%, 97.1%, 100%, and 100%, respectively, and the concordance rate was 97.14% (95% confidence interval [CI], 85.08-99.93%; p < .001). Leakage location was concordant between MRL and conventional lymphangiography in 27 patients (77.1%, 27/35). Regarding anatomical details of the thoracic duct, variation of the thoracic duct was missed in 11.7% of patients (4/34). The jugulovenous junction was observed in 91.1% (31/34), and its opening into the central vein was depicted in 76.4% (26/34). The concordance rate was between 76.47 and 91.18. CONCLUSIONS: Noncontrast MRL has a high sensitivity for the detection of postoperative thoracic and cervical chylous leakage but is suboptimal for the localization of the leak and depiction of anatomical details of the thoracic duct. This method is worthy of consideration as either a decision-making or planning tool for subsequent interventions. KEY POINTS: • Noncontrast MRL provides limited resolution images of CLS but has a high sensitivity for the detection of postoperative chylous leakage in the thoracic and neck regions. • Noncontrast MRL is suboptimal for depicting anatomic details in the thoracic duct and jugulovenous junction but can play a role as a decision-making and a planning tool for subsequent lymphatic interventions.

Thoracic Duct Lymphangiography via the Testicular Parenchyma in a Rabbit Model.

This study aimed to establish an animal model for thoracic duct lymphangiography using ethiodized oil. Thoracic duct lymphangiography was performed via the testes in 21 Japanese white rabbits. The testicular parenchyma was punctured by palpation using a 30-gauge, 0.5-inch needle. Ethiodized oil was injected at a rate of 11.41 mL/h until the testicular efferent lymphatic vessels were delineated and then at a rate of 2.85 mL/h until the entire thoracic duct was delineated. Thoracic duct delineation was 100% successful and showed good depiction based on visual scores. The mean ethiodized oil dose administered was 4.59 mL ± 1.41, and the mean time to visualize the entire thoracic duct was 43.7 minutes ± 14.1. The presented model may serve as a method for future preclinical investigation of the thoracic duct anatomy and for thoracic duct interventions.

Thoracic Duct Embolization Using Transabdominal Antegrade and Transcervical Retrograde Accesses.

PURPOSE: To evaluate the technical success and clinical outcomes of thoracic duct embolization (TDE) using transabdominal antegrade and transcervical retrograde accesses to treat patients with chyle leak. MATERIALS AND METHODS: This study was a retrospective, nonblinded, single-institution chart review of all patients aged 18 years or older over a 6-year time frame who underwent lymphangiography with attempted TDE for iatrogenic or spontaneous chyle leaks using transabdominal antegrade and/or transcervical retrograde accesses. RESULTS: Ninety-nine patients underwent 113 procedures. Eighty-five patients underwent 1 procedure, and 14 patients required 2 procedures. The technical success rate of TDE was 68% (72/106) with transabdominal antegrade access and 44% (15/34) with transcervical retrograde access. The overall technical success rate of TDE, including both the access methods, was 77% (87/113). The most common reasons for transabdominal access failure were small caliber of the cisterna chyli and thoracic duct (TD) occlusion. Five patients were lost to follow-up. Overall clinical success, defined as resolution of the chyle leak, was achieved in 83% (78/94) of the patients. There were 6 Society of Interventional Radiology (SIR) level 1 adverse events (AEs), 5 SIR level 2 AEs, and 2 SIR level 3 AEs. Nontarget embolization occurred in 2 patients. CONCLUSIONS: Although transcervical retrograde TDE is a challenging procedure, with a lower technical success rate than transabdominal antegrade access, retrograde access improved the technical and clinical success rates of the treatment of chyle leaks in cases of thoracic duct occlusion, small cisterna chyli, and leaks located in the abdomen.

Percutaneous Radiofrequency Ablation to Occlude the Thoracic Duct: Preclinical Studies in Swine for a Potential Alternative to Embolization.

PURPOSE: To investigate the feasibility of percutaneous radiofrequency (RF) ablation to occlude the thoracic duct (TD) in a swine model with imaging and histologic correlation. MATERIALS AND METHODS: Six swine underwent TD RF ablation. Two terminal (4 hours, 1 open and 1 percutaneous) and 4 survival (30 days, all percutaneous) studies were performed. Two 20-gauge needles were placed adjacent to the TD under direct visualization after right thoracotomy or under fluoroscopic guidance using a percutaneous transabdominal approach after intranodal lymphangiography. RF electrodes were advanced through the needles, and ablation was performed at 90°C for 90 seconds. Lymphangiography was performed, and the TD and adjacent structures were resected and examined microscopically at the end of each study period. RESULTS: Four of 6 subjects survived the planned study period and underwent follow-up lymphangiography. Two subjects in the survival group were euthanized early-1 after developing an acute chylothorax and 1 because of gastric volvulus 14 days after ablation. Occlusion of the targeted TD segment was noted on lymphangiography in 3 of the 4 remaining subjects (2 acute and 1 survival). Histology 4 hours after RF ablation demonstrated necrosis of the TD wall and hemorrhage within the lumen. Histology at 14 and 30 days revealed fibrosis with hemosiderin-laden macrophages replacing the ablated TD. Collagen degeneration within the aortic wall involving a maximum of 60% thickness was noted in 5 of the 6 subjects. CONCLUSIONS: Percutaneous RF ablation can achieve short-segment TD occlusion. Further study is needed to improve safety and demonstrate clinical efficacy in treating TD leaks.

Imaging Findings of Thoracic Lymphatic Abnormalities.

The lymphatic system plays an important role in balancing fluid compartments in the body. It is disrupted by various disease processes in the thorax, including injury to the thoracic lymphatic duct after surgery, as well as malignancy and heart failure. Because of the small size of lymphatic vessels, imaging of the lymphatics is relatively difficult, and effective imaging methods are still being optimized and developed. The standard of reference for lymphatic imaging has been conventional lymphangiography for several decades. Other modalities such as CT, noncontrast or contrast-enhanced MRI, and lymphoscintigraphy can also demonstrate lymphatic abnormalities and help in treatment planning. Imaging findings associated with lymphatic abnormalities can be seen in the pulmonary parenchyma, pleural space, and mediastinum. In the pulmonary parenchyma, common findings include interlobular septal thickening as well as reversal of lymphatic flow with intravasation of contrast material into pulmonary lymphatics. In the pleural space, findings include chylous pleural effusion and occasionally nonchylous pleural effusion. In the mediastinum, thoracic duct leak, plexiform thoracic duct, lymphatic malformations, and lymphangiectasis may occur. Management of chylothorax includes conservative or medical treatment, surgery, and interventional radiology procedures. The authors discuss thoracic lymphatic anatomy, imaging manifestations of lymphatic abnormalities in the various anatomic compartments, and interventional radiology treatment of chylothorax. Radiologists should be familiar with these imaging findings for diagnosis and to help guide appropriate management. ©RSNA, 2022.