This is a novel case of idiopathic chylopericardium and chylothorax in a young male who had no significant medical history. He first presented with dyspnea due to idiopathic chylopericardium, which was refractory to medical and surgical treatments, including a medium-chain triglyceride diet, octreotide, and video-assisted pericardial window. The chylopericardium persisted and progressed to concomitant left-sided chylothorax. He subsequently underwent multiple imaging studies, including lymphoscintigraphy and an intranodal lymphangiogram, both of which confirmed leakage in the thoracic duct. Finally, thoracic duct embolization was performed via a retrograde transvenous approach, which was successful, with good results. Although idiopathic chylopericardium and chylothorax are extremely rare, it can greatly impact patient quality of life if left undiagnosed and untreated. While surgery can relieve cardiac tamponade, lymphatic imaging and intervention are key in diagnosing and treating the root cause of the condition. This case highlights the importance of multidisciplinary efforts in managing rare cases and how interventional radiology is a minimally invasive but effective way to treat thoracic duct leakage. Retrograde thoracic duct embolization is technically challenging but safe and effective.

Background: The thoracic duct (TD) and the cisterna chyli (CC) exhibit a high degree of variability in their topographical and morphometric properties. Materials and Methods: PubMed, Scopus, Embase, Web of Science, Cochrane Library, and Google Scholar were searched to identify all studies that included information regarding the morphometric and topographical characteristics of the TD and CC. Results: The most frequent location of the TD termination was the left venous angle, with a pooled prevalence of 45.29% (95% CI: 25.51-65.81%). Moreover, the TD terminated most commonly as a single vessel (pooled prevalence = 78.41%; 95% CI: 70.91-85.09%). However, it divides into two or more terminating branches in approximately a quarter of the cases. The pooled prevalence of the CC was found to be 55.49% (95% CI: 26.79-82.53%). Conclusions: Our meta-analysis reveals significant variability in the anatomy of the TD and CC, particularly regarding TD termination patterns. Despite the predominance of single-vessel terminations, almost a quarter of cases exhibit branching, highlighting the complexity of the anatomy of the TD. These findings demonstrate the importance of detailed anatomical knowledge for surgeons to minimize the risk of accidental injury during head and neck, as well as thoracic surgeries. Our study provides essential insights that can enhance surgical safety and efficacy, ultimately improving patient outcomes.

Lymphatic complications in patients with single ventricle include plastic bronchitis, protein-losing enteropathy, and chylous pleural effusion are a source of significant morbidity and mortality with historically limited therapeutic options. Novel lymphatic imaging techniques such as intranodal lymphangiography, dynamic contrast enhanced magnetic resonance lymphangiography and liver lymphangiography have allowed visualization of the lymphatic system and discovery of the pathophysiological mechanism of these conditions. This mechanism includes the combination of 2 factors: increased lymphatic flow in patients with elevated central venous pressure and presence of the lymphatic anatomical variant that allows the lymph to flow in close proximity to the serous (pleural space in chylothorax) or mucosal (plastic bronchitis and protein losing enteropathy) surfaces. Novel minimally invasive lymphatic interventional techniques, such as thoracic duct embolization, interstitial embolization and liver lymphatic embolization have allowed the obliteration of these abnormal lymphatic networks, resulting in resolution of the symptoms. Further refinement of the imaging techniques and interventional methods have subsequently allowed better patient selection and improved long term outcome of these procedures.

Thoracic duct embolization (TDE) has become the standard treatment for atraumatic and traumatic chylothoraces. Numerous approaches to embolization including intranodal lymphangiography, transabdominal, and retrograde catheterization of the thoracic duct have become the preferred methods for the treatment of chyle leaks. The purpose of this study was to determine training, treatment techniques, outcomes, and practice patterns of practitioners performing TDE.

From September to October of 2017, a 34-question survey focusing on training, treatment techniques, outcomes, and practice patterns of TDE was distributed through the Open Forum of the Society of Interventional Radiology Connect website. Fifty-four practitioners completed the entire survey. Percentages were calculated for answers to the questions. Chi-squared analysis was performed, comparing data from academic center respondents, private practice settings, and hybrid practice settings. P values < 0.5 were considered statistically significant.

All responses were from interventional radiologists. Forty-seven practitioners (87.0%) performed TDE in the United States, and 1 performed (1.9%) abroad; 6 practitioners (11.1%) did not perform TDE. Of all, 88.9% (n = 48) performed TDE in academic (n = 24; 50%), private (n = 17; 35.4%), or hybrid (n = 6; 12.5%) practice settings. For diagnostic lymphangiography, 100% (n = 48) performed intranodal pelvic lymphangiography. A 25-gauge needle was used by 77.1% (n = 37) to access pelvic lymph nodes, and most (83.3%; n = 40) reported using manual hand injection to administer ethiodized oil. Nine of 24 (37.5%) respondents in academic practice and 15 of 23 (65.2%) in private practice were successful in cannulating the thoracic duct >80% of the time. Most referrals were from thoracic surgery (n = 47; 97.9%).

TDE is performed by practitioners in both academic and private practice settings. Treatment techniques were similar for a majority of operators. Technical success rates were higher in private practice. Most referrals were from thoracic surgery.

Currently, lymphedema (LED) is typically diagnosed clinically on the basis of a patient's history and characteristic physical findings. Whereas the diagnosis of LED is sometimes confirmed by lymphoscintigraphy (LSG), the technique is limited in both its ability to identify disease and to guide therapy. Recent advancements provide opportunities for new imaging techniques not only to assist in the diagnosis of LED, based on anatomic changes, but also to assess contractile function and to guide therapeutic intervention. The purpose of this contribution was to review these imaging techniques.

Literature for each technique is reviewed and discussed, and the evidence for each of these new diagnostic techniques was assessed on several criteria to determine if each could (1) establish whether disease is present, (2) determine the severity of the disease process, (3) define the pathophysiologic mechanism of the disease process, (4) demonstrate whether intervention is possible as well as what type, and (5) objectively grade the response to therapy.

LSG is currently the standard test to confirm LED. Duplex ultrasound (DUS) is a simple, readily available noninvasive test that can identify LED by specific tissue characteristics as well as the response to therapy. Magnetic resonance imaging and computed tomography scans similarly demonstrate the alterations in epidermal and subcutaneous tissue, but the latter can also detect obstructing neoplasms as a cause of secondary LED. Moreover, magnetic resonance lymphangiography details lymphatic vessels and nodes and their function. Newer fluorescence imaging techniques provide opportunities to image lymphatic anatomy and function. Visible microlymphangiography by fluorescein sodium is limited by tissue light absorption to imaging depths of 200 μm. Near-infrared fluorescence lymphatic imaging, a newer test using intradermal injection of indocyanine green, can penetrate several centimeters of tissue and can visualize the initial and conducting lymphatics, the lymph node basins, and the active function of lymphangions (the key module) in exquisite detail.

The availability and the noninvasive nature of DUS should make this modality the first choice for establishing the diagnosis of LED based on tissue changes. Further studies comparing DUS with LSG, however, are needed. The costs of magnetic resonance imaging and computed tomography limit their adoption as a means to regularly assess the lymphatics. Whereas lymphatic truncal anatomy and transit times can be delineated by the older technique of LSG, near-infrared fluorescence lymphatic imaging is rapid, highly sensitive, and repeatable and provides exquisite detail for lymphatic vessel anatomy and function of the lymphangions as well as the response to therapy.

The thoracic duct is the body's largest lymphatic conduit, draining upwards of 75 % of lymphatic fluid and extending from the cisterna chyli to the left jugulovenous angle. While a typical course has been described, it is estimated that it is present in only 40-60% of patients, often complicating already challenging interventional procedures. The lengthy course predisposes the thoracic duct to injury from a variety of iatrogenic disruptions, as well as spontaneous benign and malignant lymphatic obstructions and idiopathic causes. Disruption of the thoracic duct frequently results in chylothoraces, which subsequently cause an immunocompromised state, contribute to nutritional depletion, and impair respiratory function. Although conservative dietary treatments exist, the majority of thoracic duct disruptions require embolization in the interventional suite. This article provides a comprehensive review of the clinical importance of the thoracic duct, relevant anatomic variants, imaging, and embolization techniques for both diagnostic and interventional radiologists as well as for the general medical practitioner.

• Describe clinical importance, embryologic origin, and typical course of the thoracic duct. • Depict common/lesser-known thoracic duct anatomic variants and discuss their clinical significance. • Outline the common causes of thoracic duct injury and indications for embolization. • Review the thoracic duct embolization procedure including both pedal and intranodal approaches. • Present and illustrate the success rates and complications associated with the procedure.