Postoperative chylous ascites successfully managed by selective lymphatic embolization: Case report and literature review

Postoperative chylous ascites is a rare complication following retroperitoneal surgeries, presenting significant challenges in diagnosis and management. Retroperitoneal cyst surgery resulting in chylous leaks is an uncommon complication that has not been previously reported in the literature. Therefore, we report a clinical case of postoperative chylous ascites following retroperitoneal cyst removal with underlying idiopathic thoracic duct obstruction. This case report details the clinical features and imaging characteristics, as well as provides insights into the diagnosis of chylous leaks and the management of selective embolization of the lymphatic branches in the lumbar region.

Ultrasound-guided needle positioning confirmation with injection of saline solution for nodal dynamic contrast-enhanced MR-lymphangiography in pediatric patients

PURPOSE

To assess the success rate of confirmation of ultrasound-guided intranodal needle positioning by saline injection for dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) in pediatric patients.

MATERIAL AND METHODS

Data from children undergoing nodal DCMRL after ultrasound-guided needle positioning into inguinal lymph nodes and validation of the needle position by injection of plain saline solution between 05/2020 and 12/2022 were reviewed. On injection of saline solution, adequate needle position was confirmed by lymph node distension without leakage. Detection rates and lymph node diameters were recorded. Technical success of needle placement was defined as enhancement of ipsilateral iliac draining lymph vessels on DCMRL, while clinical success was based on enhancement of central lymphatics and/or lymphatic pathologies being observed.

RESULTS

One hundred sixteen DCMRL were performed in 90 children (58 male, mean age 6.1 years, range 3 weeks-18 years). In 232/232 groins lymph nodes were identified on ultrasound with a mean diameter of 2.5 mm (smallest diameter 1 mm in n = 24 patients). Due to skin inflammation, no puncture was performed in 2/232 groins. Saline injection showed lymph node distension in 230/230 punctured nodes. On MR contrast injection enhancement of draining lymph vessels was seen in 228/230 nodes. In 1/230 nodes, in-bore needle retraction led to lymphatic enhancement, so a total of 229/230 needle placements were technically successful. One of the 230 DCMRLs was successful with only a unilateral contrast application. Overall, 116/116 DCMRLs were clinically successful.

CONCLUSION

Confirmation of ultrasound-guided needle positioning for nodal DCMRL using saline injection is a reliable technique with a very high success rate in pediatric patients with small lymph nodes.

KEY POINTS

Question Evaluation of ultrasound-guided injection needle positioning for dynamic contrast-enhanced MR-lymphangiography in children requires validation. Findings Confirmation of needle positioning by ultrasound-guided saline injection is a reliable technique with a very high success rate for MR-lymphangiography in pediatric patients. Clinical relevance Intranodal needle position for dynamic contrast-enhanced lymphangiography can be confirmed with a very high success rate using saline injection alone in a pediatric cohort.

Dynamic contrast-enhanced magnetic resonance lymphangiography: a simple algorithm for image interpretation

Dynamic contrast-enhanced magnetic resonance lymphangiography is a high-resolution imaging technique that has emerged as the preferred method for evaluating lymphatic anatomy and flow dynamics due to its precise anatomical detail. The lymphatic system has a complex anatomical distribution, and variability is common among individuals with cardiac abnormalities, particularly congenital heart disease. Lymphatic imaging has recently been revolutionized by the introduction of MR lymphangiography. However, challenges in interpreting these images persist due to limited availability of this modality, and the expertise required for its performance and interpretation, especially in pediatric patients. We aim to outline a simple algorithm employed in our practice for interpreting MR lymphangiography images for pediatric radiologists.

Lymphatic System Development and Function

PURPOSE OF REVIEW

This review delves into recent advancements in understanding generalized and organ-specific lymphatic development. It emphasizes the distinct characteristics and critical anomalies that can impair lymphatic function. By exploring developmental mechanisms, the review seeks to illuminate the profound impact of lymphatic malformations on overall health and disease progression.

RECENT FINDINGS

The introduction of genome sequencing, single-cell transcriptomic analysis, and advanced imaging technologies has significantly enhanced our ability to identify and characterize developmental defects within the lymphatic system. As a result, a wide range of lymphatic anomalies have been uncovered, spanning from congenital abnormalities present at birth to conditions that can become life-threatening in adulthood. Additionally, recent research highlights the heterogeneity of lymphatics, revealing organ-specific developmental pathways, unique molecular markers, and specialized physiological functions specific to each organ. A deeper understanding of the unique characteristics of lymphatic cell populations in an organ-specific context is essential for guiding future research into lymphatic disease processes. An integrated approach to translational research could revolutionize personalized medicine, where treatments are precisely tailored to individual lymphatic profiles, enhancing effectiveness and minimizing side effects.

Clinical approach for pulmonary lymphatic disorders

In this editorial, we discuss the clinical implications of the article "Lymphatic plastic bronchitis and primary chylothorax: A study based on computed tomography lymphangiography" published by Li et al. Pulmonary lymphatic disorders involve abnormalities in the lymphatic tissues within the thoracic cavity. Specifically, pulmonary lymphatic perfusion syndrome describes a condition where the flow of lymphatic fluid in the lungs is redirected towards abnormally widened lymphatic vessels. Clinically, individuals with this syndrome may experience symptoms such as chyloptysis, plastic bronchitis (PB), chylothorax, chylopericardium, and interstitial lung disease. These disorders can be caused by various factors, including PB, chylothorax, and complex lymphatic malformations. Advancements in lymphatic imaging techniques, such as intranodal lymphangiography, computed tomography lymphangiography, and dynamic contrast-enhanced magnetic resonance lymphangiography, have enabled the detection of abnormal lymphatic flow. This has enhanced our understanding of the pathophysiology of these conditions. Additionally, innovative minimally invasive treatments, such as thoracic duct embolization, selective embolization of lymphatic channels, and surgical procedures aim to improve clinical condition of patients and address their dietary needs.

Lymphatic Malformations: Review of Diagnosis and Management for the Interventional Radiologist

Lymphatic malformations (LMs) arise from errors in lymphatic vascular development during embryogenesis and encompass an array of conditions that span from common cystic LMs to complex lymphatic anomalies (CLAs). Manifestations of LMs are wide-ranging, from clinically inconsequential to life-threatening. Proper diagnosis and management can be challenging and often benefit from an experienced multidisciplinary team. Cystic LMs are localized entities for which percutaneous sclerotherapy is the mainstay treatment. CLAs, on the other hand, are more diffuse in involvement and typically require multimodal therapy. With advances in the genetic understanding of LMs, targeted systemic therapies have been increasingly utilized with promising results. Thoracic duct interventions, both surgical and percutaneous, have a limited role in CLAs and should be approached cautiously to avoid significant complications. In this review, we discuss the genetic basis, imaging findings, and management options for LMs, with a particular focus on relevant interventional radiology techniques.

State-of-the-art imaging for children with central lymphatic disorders

Lymphatic imaging plays a crucial role in novel lymphatic interventions, offering valuable insights into central lymphatic drainage. Lymphatic system abnormalities may appear in various pediatric disorders, and accurate imaging is crucial for effective diagnosis and tailored therapeutic interventions. Traditional imaging modalities have offered valuable insights, but the demand for non-invasive, high-resolution techniques has fueled the development of innovative lymphatic imaging methods. In this review, we explore the state of the art in lymphatic imaging specifically within the context of pediatric surgery.

Surgical management of chronic lymphatic pleural effusions and chronic lymphatic ascites

Patients with central lymphatic conduction disorders commonly have recalcitrant pleural effusions and or ascites. These conditions cause a profound deterioration in the patient's quality of life. Support measures such as low-fat diet and diuretics alone hardly ever provide meaningful improvement. New understanding of the pathophysiology of these disorders has opened the door in recent years to the development of several surgical procedures that have remarkable success rates. However, these patients must be managed by expert multidisciplinary teams.

Management of Idiopathic Infantile Chylous Ascites

Chylous ascites is the accumulation of triglyceride-rich lymphatic fluid in the peritoneal cavity. We present the case of a four-month-old male admitted for abdominal distension. A large volume of ascites was confirmed by imaging. Paracentesis indicated chylous aspirate and drainage was performed using a pigtail catheter. Total parenteral nutrition was initiated and fluconazole prophylaxis was implemented for seven days. Twenty-six days after admission, abdominopelvic magnetic resonance imaging showed trace ascites but no signs of lymphatic malformation. He began transitioning to nasogastric feeds with plans to eventually resume oral feeds. This case not only highlights the limitations in our abilities to definitively identify the etiology of pediatric chylous ascites but also demonstrates how chylous ascites management can carefully combine conservative and surgical strategies to optimize patient outcomes.

MR Lymphangiography in Lymphatic Disorders: Clinical Applications, Institutional Experience, and Practice Development

Lymphatic flow and anatomy can be challenging to study, owing to variable lymphatic anatomy in patients with diverse primary or secondary lymphatic pathologic conditions and the fact that lymphatic imaging is rarely performed in healthy individuals. The primary components of the lymphatic system outside the head and neck are the peripheral, retroperitoneal, mesenteric, hepatic, and pulmonary lymphatic systems and the thoracic duct. Multiple techniques have been developed for imaging components of the lymphatic system over the past century, with trade-offs in spatial, temporal, and contrast resolution; invasiveness; exposure to ionizing radiation; and the ability to obtain information on dynamic lymphatic flow. More recently, dynamic contrast-enhanced (DCE) MR lymphangiography (MRL) has emerged as a valuable tool for imaging both lymphatic flow and anatomy in a variety of congenital and acquired primary or secondary lymphatic disorders. The authors provide a brief overview of lymphatic physiology, anatomy, and imaging techniques. Next, an overview of DCE MRL and the development of an MRL practice and workflow in a hybrid interventional MRI suite incorporating cart-based in-room US is provided, with an emphasis on multidisciplinary collaboration. The spectrum of congenital and acquired lymphatic disorders encountered early in an MRL practice is provided, with emphasis on the diversity of imaging findings and how DCE MRL can aid in diagnosis and treatment of these patients. Methods such as DCE MRL for assessing the hepatic and mesenteric lymphatic systems and emerging technologies that may further expand DCE MRL use such as three-dimensional printing are introduced. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Novel Techniques in Imaging Congenital Heart Disease: JACC Scientific Statement

Recent years have witnessed exponential growth in cardiac imaging technologies, allowing better visualization of complex cardiac anatomy and improved assessment of physiology. These advances have become increasingly important as more complex surgical and catheter-based procedures are evolving to address the needs of a growing congenital heart disease population. This state-of-the-art review presents advances in echocardiography, cardiac magnetic resonance, cardiac computed tomography, invasive angiography, 3-dimensional modeling, and digital twin technology. The paper also highlights the integration of artificial intelligence with imaging technology. While some techniques are in their infancy and need further refinement, others have found their way into clinical workflow at well-resourced centers. Studies to evaluate the clinical value and cost-effectiveness of these techniques are needed. For techniques that enhance the value of care for congenital heart disease patients, resources will need to be allocated for education and training to promote widespread implementation.

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.

A Case of Lymphangioma of the Calf Region: Imaging Spectrum With Histopathological Correlation

Lymphangioma, also known as cystic hygroma are benign malformations arising from abnormal development of the lymphatic system. Most often these lesions are found in the pediatric population, having a predilection for the neck/axilla, and are less common in extremities. Symptoms can vary based on size and location. Treatment is not usually indicated until they start impacting life due to deformity or symptoms such as pain, paraesthesia, etc. Here, we report a case report of lymphangioma located in the calf region of the right lower limb presenting in adult age.

The emerging importance of lymphatics in health and disease: an NIH workshop report

The lymphatic system (LS) is composed of lymphoid organs and a network of vessels that transport interstitial fluid, antigens, lipids, cholesterol, immune cells, and other materials in the body. Abnormal development or malfunction of the LS has been shown to play a key role in the pathophysiology of many disease states. Thus, improved understanding of the anatomical and molecular characteristics of the LS may provide approaches for disease prevention or treatment. Recent advances harnessing single-cell technologies, clinical imaging, discovery of biomarkers, and computational tools have led to the development of strategies to study the LS. This Review summarizes the outcomes of the NIH workshop entitled "Yet to be Charted: Lymphatic System in Health and Disease," held in September 2022, with emphasis on major areas for advancement. International experts showcased the current state of knowledge regarding the LS and highlighted remaining challenges and opportunities to advance the field.

Back to the Future II-A Comprehensive Update on the Rapidly Evolving Field of Lymphatic Imaging and Interventions

ABSTRACT

Lymphatic imaging and interventional therapies of disorders affecting the lymphatic vascular system have evolved rapidly in recent years. Although x-ray lymphangiography had been all but replaced by the advent of cross-sectional imaging and the scientific focus shifted to lymph node imaging (eg, for detection of metastatic disease), interest in lymph vessel imaging was rekindled by the introduction of lymphatic interventional treatments in the late 1990s. Although x-ray lymphangiography is still the mainstay imaging technique to guide interventional procedures, several other, often less invasive, techniques have been developed more recently to evaluate the lymphatic vascular system and associated pathologies. Especially the introduction of magnetic resonance, and even more recently computed tomography, lymphangiography with water-soluble iodinated contrast agent has furthered our understanding of complex pathophysiological backgrounds of lymphatic diseases. This has led to an improvement of treatment approaches, especially of nontraumatic disorders caused by lymphatic flow abnormalities including plastic bronchitis, protein-losing enteropathy, and nontraumatic chylolymphatic leakages. The therapeutic armamentarium has also constantly grown and diversified in recent years with the introduction of more complex catheter-based and interstitial embolization techniques, lymph vessel stenting, lymphovenous anastomoses, as well as (targeted) medical treatment options. The aim of this article is to review the relevant spectrum of lymphatic disorders with currently available radiological imaging and interventional techniques, as well as the application of these methods in specific, individual clinical situations.

The spectrum of imaging manifestations of Gorham-Stout disease: a novel dynamic contrast-enhanced MR lymphangiography

BACKGROUND

To describe the radiological features of Gorham-Stout disease (GSD) as evaluated using plain radiography and dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) imaging techniques.

METHODS

Clinical and conventional imaging data were retrospectively reviewed for 15 patients with GSD between January 2001 and December 2020. After December 2018, DCMRL examinations were performed for lymphatic vessel evaluation in patients with GSD and reviewed in four patients.

RESULTS

The median age at diagnosis was 9 years (range: 2 months-53 years). The clinical manifestations were dyspnea in seven patients (46.7%), sepsis in 12 (80.0%), orthopedic problems in seven (46.7%), and bloody chylothorax in seven (46.7%). The common sites of osseous involvement were the spine (73.3%) and pelvic bone (60.0%). Among the non-osseous involvements, peri-osseous infiltrative soft-tissue abnormalities adjacent to the area of bone involvement were the most common (86.7%), followed by splenic cysts (26.7%) and interstitial thickening (26.7%). DCMRL demonstrated weak central conducting lymphatic flow in two patients with abnormal giant tortuous thoracic ducts and no flow in one patient. All patients who underwent DCMRL in this study presented with altered anatomical lymphatics and functional flow with collateralization.

CONCLUSION

DCMRL imaging and plain radiography are very useful for determining the extent of GSD. DCMRL is a novel imaging tool for the visualization of abnormal lymphatics in patients with GSD, which helps in further treatment. Therefore, in patients with GSD, it might be necessary to obtain not only plain radiographs but also MR and DCMRL images.

MRI of Lymphedema

Lymphedema is a devastating disease that has no cure. Management of lymphedema has evolved rapidly over the past two decades with the advent of surgeries that can ameliorate symptoms. MRI has played an increasingly important role in the diagnosis and evaluation of lymphedema, as it provides high spatial resolution of the distribution and severity of soft tissue edema, characterizes diseased lymphatic channels, and assesses secondary effects such as fat hypertrophy. Many different MR techniques have been developed for the evaluation of lymphedema, and the modality can be tailored to suit the needs of a lymphatic clinic. In this review article we provide an overview of lymphedema, current management options, and the current role of MRI in lymphedema diagnosis and management. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 5.

Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography and Lymphatic Interventions for Pediatric Patients with Various Lymphatic Diseases

Background: To demonstrate the magnetic resonance lymphangiography (MRL) imaging findings of lymphatic diseases and the clinical outcomes of lymphatic embolization in pediatric patients. Methods and Results: This retrospective study included 10 consecutive pediatric patients who underwent MRL for lymphatic diseases between June 2017 and June 2021. Nine patients underwent dynamic contrast-enhanced MRL with bilateral inguinal lymph node injection of diluted gadolinium, and one patient underwent nonenhanced MRL with a heavily T2-weighted image. The etiology of lymphatic disease was classified into three categories based on the magnetic resonance findings. The resolution of chylous fluid and weight-adjusted amounts of chylous fluid collected from a drainage tube were evaluated as outcomes. Patients were classified as postoperative lymphatic leak (n = 3), pulmonary lymphatic perfusion syndrome (n = 3), central lymphatic flow disorder (CLFD; n = 3), and primary lymphatic dysfunction (Gorham-Stout syndrome; n = 1). Three patients underwent radiological lymphatic intervention, and one CLFD patient underwent surgical intervention. In patients with postoperative lymphatic leak, the median chest tube drainage decreased significantly after the intervention [from 87.9 to 12.4 mL/(kg·d); p = 0.02]. However, in one CLFD patient, the amount of chylous fluid did not decrease until 7 days after intervention. Conclusion: The etiology of lymphatic disease in pediatrics can be recognized on MRL, and lymphatic intervention can be performed for cessation of lymphatic leak, even though the treatment outcomes may differ according to the underlying etiology. MRL can play an important role in classifying lymphatic disease, and in planning treatment on the basis of the lymphatic anatomy and underlying etiology.

Intranodal dynamic contrast-enhanced CT lymphangiography and dynamic contrast-enhanced MR lymphangiography in microminipig

OBJECTIVES

To evaluate the feasibility and image quality of intranodal dynamic contrast-enhanced CT lymphangiography (DCCTL) and dynamic contrast-enhanced MR lymphangiography (DCMRL) in microminipigs.

METHODS

Our institution's committee for animal research and welfare provided approval. Three microminipigs underwent DCCTL and DCMRL after inguinal lymph node injection of 0.1 mL/kg contrast media. Mean CT values on DCCTL and signal intensity (SI) on DCMRL were measured at the venous angle and thoracic duct (TD). The contrast enhancement index (CEI; increase in CT values pre- to post-contrast) and signal intensity ratio (SIR; SI of lymph divided by SI of muscle) were evaluated. The morphologic legibility, visibility, and continuity of lymphatics were qualitatively evaluated using a 4-point scale. Two microminipigs underwent DCCTL and DCMRL after lymphatic disruption and the detectability of lymphatic leakage was evaluated.

RESULTS

The CEI peaked at 5-10 min in all microminipigs. The SIR peaked at 2-4 min in two microminipigs and at 4-10 min in one microminipig. The peak CEI and SIR values were 235.6 HU and 4.8 for venous angle, 239.4 HU and 2.1 for upper TD, and 387.3 HU and 2.1 for middle TD. The visibility and continuity of upper-middle TD scores were 4.0 and 3.3-3.7 for DCCTL, and 4.0 and 4.0 for DCMRL. In the injured lymphatic model, both DCCTL and DCMRL demonstrated lymphatic leakage.

CONCLUSIONS

DCCTL and DCMRL in a microminipig model enabled excellent visualization of central lymphatic ducts and lymphatic leakage, indicating the research and clinical potential of both modalities.

KEY POINTS

• Intranodal dynamic contrast-enhanced computed tomography lymphangiography showed a contrast enhancement peak at 5-10 min in all microminipigs. • Intranodal dynamic contrast-enhanced magnetic resonance lymphangiography showed a contrast enhancement peak at 2-4 min in two microminipigs and at 4-10 min in one microminipig. • Both intranodal dynamic contrast-enhanced computed tomography lymphangiography and dynamic contrast-enhanced magnetic resonance lymphangiography demonstrated the central lymphatic ducts and lymphatic leakage.

Mapping the lymphatic system across body scales and expertise domains: A report from the 2021 National Heart, Lung, and Blood Institute workshop at the Boston Lymphatic Symposium

Enhancing our understanding of lymphatic anatomy from the microscopic to the anatomical scale is essential to discern how the structure and function of the lymphatic system interacts with different tissues and organs within the body and contributes to health and disease. The knowledge of molecular aspects of the lymphatic network is fundamental to understand the mechanisms of disease progression and prevention. Recent advances in mapping components of the lymphatic system using state of the art single cell technologies, the identification of novel biomarkers, new clinical imaging efforts, and computational tools which attempt to identify connections between these diverse technologies hold the potential to catalyze new strategies to address lymphatic diseases such as lymphedema and lipedema. This manuscript summarizes current knowledge of the lymphatic system and identifies prevailing challenges and opportunities to advance the field of lymphatic research as discussed by the experts in the workshop.

Lymphatic Intervention, the Frontline of Modern Lymphatic Medicine: Part II. Classification and Treatment of the Lymphatic Disorders

Lymphatic disorders encompass a broad spectrum of diseases involving the lymphatic system, ranging from traumatic lymphatic leaks to lymphatic malformations. Lymphatic disorders can be categorized into traumatic and non-traumatic disorders according to their etiology. These two categories may be further divided into subgroups depending on the anatomical location of the lymphatic pathology and their association with clinical syndromes. Thoracic duct embolization was a milestone in the field of lymphatic intervention that encouraged the application of percutaneous embolization techniques to treat leaks and reflux disorders in the lymphatic system. Additional access routes for embolization, including retrograde thoracic duct and transhepatic lymphatic access, have also been developed. This article comprehensively reviews a variety of options for the treatment of lymphatic disorders, from conservative management to the most recent embolization techniques.

Fusion imaging of single-photon emission computed tomography and magnetic resonance lymphangiography for post-Fontan chylothorax

A preschool male patient with an extensive cardiac surgical history developed refractory chylothorax after a total cavopulmonary connection. Neither lymphoscintigraphy nor single-photon emission computed tomography (SPECT)/computed tomography could identify the lymphatic system leakage sites. Non-contrast heavy T2-weighted magnetic resonance lymphangiography (MRL) was performed to visualize the lymphatic system. Nevertheless, distinguishing lymphatic ducts from other watery structures of the patient remained difficult. Therefore, non-contrast MRL and SPECT images were fused. This hybrid diagnostic tool elucidated the pathophysiology of the prolonged chylothorax; pulmonary lymphatic perfusion syndrome and illustrated the anatomical connection of the thoracic duct and an abnormally dilated lymphatic network in the neck and left hilar regions. Subsequent intranodal lymphangiography with ethiodized oil confirmed these findings. SPECT/MRL may become an alternative modality for revealing the mechanism of prolonged chylothorax by visualizing the lymphatic system when dynamic contrast-enhanced magnetic resonance lymphangiography is unavailable.

Lymphatic Intervention, the Frontline of Modern Lymphatic Medicine: Part I. History, Anatomy, Physiology, and Diagnostic Imaging of the Lymphatic System

Recent advances in lymphatic imaging have provided novel insights into the lymphatic system. Interventional radiology has played a significant role in the development of lymphatic imaging techniques and modalities. Radiologists should be familiar with the basic physiology and anatomy of the lymphatic system to understand the imaging features of lymphatic disorders, which reflect their pathophysiology. This study comprehensively reviews the physiological and anatomical aspects of the human lymphatic system as well as the latest lymphatic imaging techniques.

Intranodal cone-beam computed tomographic lymphangiography with water-soluble iodinated contrast agent for evaluating chylothorax in infants - preliminary experience at a single institution

This brief report demonstrates the diagnostic utility of cone-beam CT lymphangiography (CBCTL) with intranodal injection of water-soluble iodinated contrast agent for assessing lymphatic disorders in two infants who were contraindicated for MRI and oil-based contrast agent. Both infants had dextro-transposition of the great arteries (d-TGA) and presented with high-output chylothoraces that were recalcitrant to conservative medical therapy. Both infants were diagnosed with central lymphatic flow disorder based on the CBCTL findings.

Invasive treatment of persistent postoperative chylothorax secondary to thoracic duct variation injury: Two case reports and literature review

RATIONALE

Postoperative chylothorax is a rare complication after pulmonary resection. Thoracic duct variations may play a key role in postoperative chylothorax occurrence and make treatment difficult. No studies in the literature have reported the successful treatment of chylothorax second to thoracic duct variation by lipiodol-based lymphangiography.

PATIENT CONCERNS

A 63-year-old male and a 28-year-old female with primary lung adenocarcinoma were treated by video-assisted thoracoscopic cancer resection, and suffered postoperative chylothorax. Conservative treatment was ineffective, including nil per os, persistent thoracic drainage, fatty food restriction, and somatostatin administration.

DIAGNOSIS

Postoperative chylothorax.

INTERVENTIONS

Patients received lipiodol-based lymphangiography under fluoroscopic guidance. Iatrogenic injuries were identified at thoracic duct variations, including an additional channel in case 1 and the lymphatic plexus instead of the thoracic duct in case 2.

OUTCOMES

Thoracic duct variations were identified by lipiodol-based lymphangiography, and postoperative chylothorax was successfully treated by lipiodol embolizing effect.

LESSONS

Thoracic duct variations should be considered after the failure of conservative treatment for postoperative chylothorax secondary to pulmonary resection. Lipiodol-based lymphangiography is valuable for identifying the thoracic duct variations and embolizing chylous leakage.

Pathophysiology, Diagnosis, and Management of Canine Intestinal Lymphangiectasia: A Comparative Review

Intestinal lymphangiectasia was first described in the dog over 50 years ago. Despite this, canine IL remains poorly understood and challenging to manage. Intestinal lymphangiectasia is characterized by variable intestinal lymphatic dilation, lymphatic obstruction, and/or lymphangitis, and is a common cause of protein-losing enteropathy in the dog. Breed predispositions are suggestive of a genetic cause, but IL can also occur as a secondary process. Similarly, both primary and secondary IL have been described in humans. Intestinal lymphangiectasia is definitively diagnosed via intestinal histopathology, but other diagnostic results can be suggestive of IL. Advanced imaging techniques are frequently utilized to aid in the diagnosis of IL in humans but have not been thoroughly investigated in the dog. Management strategies differ between humans and dogs. Dietary modification is the mainstay of therapy in humans with additional pharmacological therapies occasionally employed, and immunosuppressives are rarely used due to the lack of a recognized immune pathogenesis. In contrast, corticosteroid and immunosuppressive therapies are more commonly utilized in canine IL. This review aims toward a better understanding of canine IL with an emphasis on recent discoveries, comparative aspects, and necessary future investigations.

Interventional Management of Acquired Lymphatic Disorders

The lymphatic system is a complex network of tissues, vessels, and channels found throughout the body that assists in fluid balance and immunologic function. When the lymphatic system is disrupted related to idiopathic, iatrogenic, or traumatic disorders, lymphatic leaks can result in substantial morbidity and/or mortality. The diagnosis and management of these leaks is challenging. Modern advances in lymphatic imaging and interventional techniques have made radiology critical in the multidisciplinary management of these disorders. The authors provide a review of conventional and clinically relevant variant lymphatic anatomy and recent advances in diagnostic techniques such as MR lymphangiography. A detailed summary of technical factors related to percutaneous lymphangiography and lymphatic intervention is presented, including transpedal and transnodal lymphangiography. Traditional transabdominal access and retrograde access to the central lymph nodes and thoracic duct embolization techniques are outlined. Newer techniques including transhepatic lymphangiography and thoracic duct stent placement are also detailed. For both diagnostic and interventional radiologists, an understanding of lymphatic anatomy and modern diagnostic and interventional techniques is vital to the appropriate treatment of patients with acquired lymphatic disorders. ^©RSNA, 2022.

Lymphatic anomalies in congenital heart disease

Congenital heart disease can lead to various lymphatic complications including traumatic leaks, lymphatic overproduction, conduction abnormalities or lymphedema. Advancements in the imaging of central lymphatics and guided interventions have improved outcomes in these children. Dynamic contrast-enhanced magnetic resonance (MR) lymphangiography allows for the assessment of abnormal lymphatic drainage. This technique is preferred for evaluating lymphatic conditions such as plastic bronchitis, chylothorax, chyloptysis, chylopericardium, protein-losing enteropathy and chylous ascites, among other lymphatic disorders. In this review, we discuss lymphatic abnormalities encountered on MRI in children with congenital heart disease. We also briefly review treatment options.

State-of-the-art imaging for lymphatic evaluation in children

The lymphatic system has been poorly understood and its importance neglected for decades. Growing understanding of lymphatic flow pathophysiology through peripheral and central lymphatic flow imaging has improved diagnosis and treatment options in children with lymphatic diseases. Flow dynamics can now be visualized by different means including dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL), the current standard technique to depict central lymphatics. Novel imaging modalities including intranodal, intrahepatic and intramesenteric DCMRL are quickly evolving and have shown important advances in the understanding and guidance of interventional procedures in children with intestinal lymphatic leaks. Lymphatic imaging is gaining importance in the radiologic and clinical fields and new techniques are emerging to overcome its limitations.

Multicompartment Dynamic Contrast Magnetic Resonance Lymphangiography in Diagnosis of Complicated Lymphatic Anomaly

Background: To describe the dynamic contrast magnetic resonance lymphangiography (DCMRL) findings of three patients with complicated lymphatic anomaly (CLA) and protein losing enteropathy. We further discuss the importance of a multicompartment (intrahepatic [IH], intramesenteric [IM], and intranodal [IN]) DCMRL in delineating central lymphatic flow pathologies. Methods and Results: This is a retrospective study of three patients-one adult and two children who individually underwent the three-compartment DCMRL, namely IN-DCMRL, IH-DCMRL, and IM-DCMCRL. Findings from the results of the DCMRL for these three patients were obtained from the medical records and compared. Using the multicompartment imaging modalities, chylous fluid leakage into the peritoneum was observed using IM-DCMRL and IH-DCMRL but not IN-DCMRL for one of the patients in the case series. In contrast, leakage of chyle into the mediastinum was noted using IN-DCMRL but not IH-DCMRL and IM-DCMRL on another patient in this case series. Conclusion: Owing to the variability in outlining lymphatic flow pathologies, multicompartment imaging gives a more global picture of individual conduction disorders, has the potential to improve clinical assessment, and in some cases leads to a diagnosis of the abnormality and thus provides a better understanding of lymphatic flow anomalies in patients with CLAs.

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.

How we approach the diagnosis of a vascular anomaly

Vascular anomalies represent a diverse group of complex disorders that can cause significant complications, including coagulopathies, pain, and decreased function. The diagnosis of vascular anomalies is often challenging due to heterogeneity of presenting phenotypes and overlapping clinical features with other pediatric conditions. Pediatric hematologists/oncologists (PHO) are uniquely positioned for an essential role in diagnosing, managing, and coordinating the multidisciplinary care required to maximize the quality of life of these patients. Here, we review the diagnostic approach involved in patients with vascular anomalies and utilize cases to highlight the challenges involved, and how PHOs can play a vital part in the care of these patients.

Lymphatic Anomalies in Children: Update on Imaging Diagnosis, Genetics, and Treatment

Lymphatic anomalies comprise a spectrum of disorders ranging from common localized microcystic and macrocystic lymphatic malformations (LMs) to rare complex lymphatic anomalies, including generalized lymphatic anomaly, Kaposiform lymph-angiomatosis, central conducting lymphatic anomaly, and Gorham-Stout disease. Imaging diagnosis of cystic LMs is generally straightforward, but complex lymphatic anomalies, particularly those with multiorgan involvement or diffuse disease, may be more challenging to diagnose. Complex lymphatic anomalies are rare but associated with high morbidity. Imaging plays an important role in their diagnosis, and radiologists may be the first clinicians to suggest the diagnosis. Furthermore, radiologists are regularly involved in management given the frequent need for image-guided interventions. For these reasons, it is crucial for radiologists to be familiar with the spectrum of entities comprising complex lymphatic anomalies and their typical imaging findings. In this article, we review the imaging findings of lymphatic anomalies, including LMs and complex lymphatic anomalies. We discuss characteristic imaging findings, multimodality imaging techniques used for evaluation, pearls and pitfalls in diagnosis, and potential complications. We also review recently discovered genetic changes underlying lymphatic anomaly development and the advent of new molecularly targeted therapies.

Lymphatic Phenotype of Noonan Syndrome: Innovative Diagnosis and Possible Implications for Therapy

Dysregulation of the Ras/Mitogen-activated protein kinase (MAPK) signaling pathway is suggested to play a pivotal role in the development of the lymphatic system in patients with Noonan Syndrome (NS). Pathogenic gene variants in the Ras/MAPK pathway can therefore lead to various lymphatic diseases such as lymphedema, chylo-thorax and protein losing enteropathy. Diagnosis and treatment of the lymphatic phenotype in patients with NS remain difficult due to the variability of clinical presentation, severity and, probably, underlying unknown pathophysiologic mechanism. The objective of this article is to give an overview of the clinical presentation of lymphatic disease in relation to central conducting lymphatic anomalies (CCLA) in NS, including new diagnostic and therapeutic options. We visualized the central conducting lymphatic system using heavily T2-weighted MR imaging (T2 imaging) and Dynamic Contrast-enhanced MR Lymphangiography (DCMRL) and compared these results with the lymphatic clinical presentation in seven patients with NS. Our results show that most patients with NS and lymphatic disease have CCLA. Therefore, it is probable that CCLA is present in all patient with NS, presenting merely with lymphedema, or without sensing lymphatic symptoms at all. T2 imaging and DCMRL can be indicated when CCLA is suspected and this can help to adjust therapeutic interventions.

The lymphatic system throughout history: From hieroglyphic translations to state of the art radiological techniques

A comprehensive lymphatic system is indispensable for a well-functioning body; it is integral to the immune system and is also interrelated with the digestive system and fluid homeostasis. The main difficulty in examining the lymphatic system is its fine-meshed structure. This remains a challenge, leaving patients with uninterpreted symptoms and a dearth of potential therapies. We review the history of the lymphatic system up to the present with the aim of improving current knowledge. Several findings described throughout history have made fundamental contributions to elucidating the lymphatic system. The first contributions were made by the ancient Egyptians and the ancient Greeks. Vesalius obtained new insights by dissecting corpses. Thereafter, Ruysch (1638-1731) gained an understanding of lymphatic flow. In 1784, Mascagni published his illustration of the whole lymphatic network. The introduction of radiological lymphography revolutionized knowledge of the lymphatic system. Pedal lymphangiography was first described by Monteiro (1931) and Kinmonth (1952). Lymphoscintigraphy (nuclear medicine), magnetic resonance imaging, and near-infrared fluorescence lymphography further improved visualization of the lymphatic system. The innovative dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) transformed understanding of the central lymphatic system, enabling central lymphatic flow disorders in patients to be diagnosed and even allowing for therapeutic planning. From the perspective of the history of lymph visualization, DCMRL has ample potential for identifying specific causes of debilitating symptoms in patients with central lymphatic system abnormalities and even allows for therapeutic planning.

Ultrasound-guided needle positioning for nodal dynamic contrast-enhanced MR lymphangiography

The aim of the study was to assess injection needle positioning for contrast-enhanced MR-lymphangiography (MRL) by ultrasound-guided injection of saline-solution. 80 patients (33 male, mean age 43.1 years) were referred for MRL. The injection needle position was assessed by injection of saline-solution. Consecutive lymph node distension was observed on sonography followed by MRL. Transpedal MRL was performed when no inguinal lymph nodes could be identified. The inguinal lymph node detection rate was recorded. MR-lymphangiograms were assessed regarding primary (i.e. enhancement of draining lymph vessels) and secondary technical success (i.e. lymph vessel enhancement after repositioning of the needle). MRL was considered as clinically successful if enhancement of the central lymphatic system and/or a lymphatic pathologies were observed. For a total of 92 MRLs 177 groins were evaluated sonographically. In 171/177 groins (96.6%) lymph nodes were identified. After needle placement lymph node distension was observed in 171/171 cases (100%) on saline injection. MR-contrast injection demonstrated enhancement of draining lymph vessels in 163/171 cases (95.3%). In 6/171 cases (3.5%) in-bore needle retraction lead to lymphatic enhancement. In one patient [2/171 nodes (1.1%)] no lymphatic enhancement was seen despite repeated needle repositioning. Overall contrast application was technically successful in 169/171 cases (98.8%). In the 6 groins in which no nodes were identifiable, transpedal MRL was successful. So overall 91/92 MRLs (98.9%) were clinically successful. No complications were recorded. Confirmation of the needle position for nodal MRL by sonographically controlled saline injection is a reliable technique with a high success rate of MRL.

Understanding Lymphatic Anatomy and Abnormalities at Imaging

Lymphatic abnormalities encompass a wide range of disorders spanning solitary common cystic lymphatic malformations (LMs) to entities involving multiple organ systems such as lymphangioleiomyomatosis. Many of these disorders are rare, yet some, such as secondary lymphedema from the treatment of malignancy (radiation therapy and/or lymph node dissection), affect millions of patients worldwide. Owing to complex and variable anatomy, the lymphatics are not as well understood as other organ systems. Further complicating this is the variability in the description of lymphatic disease processes and their nomenclature in the medical literature. In recent years, medical imaging has begun to facilitate a deeper understanding of the physiology and pathologic processes that involve the lymphatic system. Radiology is playing an important and growing role in the diagnosis and treatment of many lymphatic conditions. The authors describe both normal and common variant lymphatic anatomy. Various imaging modalities including nuclear medicine lymphoscintigraphy, conventional lymphangiography, and MR lymphangiography used in the diagnosis and treatment of lymphatic disorders are highlighted. The authors discuss imaging many of the common and uncommon lymphatic disorders, including primary LMs described by the International Society for the Study of Vascular Anomalies 2018 classification system (microcystic, mixed, and macrocystic LMs; primary lymphedema). Secondary central lymphatic disorders are also detailed, including secondary lymphedema and chylous leaks, as well as lymphatic disorders not otherwise easily classified. The authors aim to provide the reader with an overview of the anatomy, pathology, imaging findings, and treatment of a wide variety of lymphatic conditions. ^©RSNA, 2022.

Protein losing enteropathy after the Fontan operation

The Fontan or Fontan Kreutzer procedure is the culmination of staged, surgical palliation of functional single ventricle congenital heart disease, offering the potential for survival and good quality of life well into adulthood. As more patients with Fontan circulation age, a variety of complications involving almost every organ system may occur. Protein-losing enteropathy is a major cause of morbidity and mortality after the Fontan operation, occurring more often in patients with adverse hemodynamics and presenting weeks to years after Fontan surgery. The causes are not well understood, but likely include a combination of lymphatic insufficiency, high central venous pressure, loss of heparan sulfate from intestinal epithelial cells, abnormal mesenteric circulation, and intestinal inflammation. A comprehensive evaluation including multimodality imaging and cardiac catheterization is necessary to diagnose and treat any reversible causes. In advanced cases, early referral for heart transplantation evaluation or lymphatic decompression procedures (if the single ventricle function remains adequate) is indicated. Despite the improvement in detection and management options, the mortality remains high. Standardization of protein-losing enteropathy definition and management strategies will help facilitate interpretation of research and clinical experience, potentially fostering the identification of new therapies. Based on the published data, this review suggests a standardized approach to diagnosis and treatment.

Dynamic contrast-enhanced magnetic resonance lymphangiography

Lymphatic flow disorders include a broad spectrum of abnormalities that can originate in the lymphatic or the venous system. The development of these disorders is multifactorial and is most commonly associated with congenital heart diseases and palliative surgeries that these patients undergo. Central lymphatic disorders might be secondary to traumatic leaks, lymphatic overproduction, conduction abnormalities or lymphedema, and they can progress to perfusion anomalies. Several imaging modalities have been used to visualize the lymphatic system. However, the imaging of central lymphatic flow has always been challenging. Dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) allows for visualization of central lymphatic flow disorders and has been recently applied for the assessment of plastic bronchitis, protein-losing enteropathy, chylothorax and chylopericardium, among other lymphatic disorders. The hepatic and mesenteric accesses are innovative and promising techniques for better identification and understanding of these abnormalities. The main objectives of this review are to discuss the physiology and anatomy of the lymphatic system and review the current uses of DCMRL in the diagnosis and management of lymphatic flow disorders.

Transcatheter interventions in patients with a Fontan circulation: Current practice and future developments

The Fontan operation represents the last of multiple steps that are offered a wide range of congenital cardiac lesions with a single ventricle (SV) physiology. Nowadays this surgical program consists of a total cavopulmonary connection (TCPC), by anastomosing systemic veins to the pulmonary arteries (PAs), excluding the right-sided circulation from the heart. As a result of imaging, surgical, percutaneous, and critical care improvements, survival in this population has steadily increased. However, the Fontan physiology chronically increases systemic venous pressure causing systemic venous congestion and decreased cardiac output, exposing patients to the failure of the Fontan circulation (FC), which is associated with a wide variety of clinical complications such as liver disease, cyanosis, thromboembolism, protein-losing enteropathy (PLE), plastic bronchitis (PB), and renal dysfunction, ultimately resulting in an increased risk of exercise intolerance, arrhythmias, and premature death. The pathophysiology of the failing Fontan is complex and multifactorial; i.e., caused by the single ventricle dysfunction (diastolic/systolic failure, arrhythmias, AV valve regurgitation, etc.) or caused by the specific circulation (conduits, pulmonary vessels, etc.). The treatment is still challenging and may include multiple options and tools. Among the possible options, today, interventional catheterization is a reliable option, through which different procedures can target various failing elements of the FC. In this review, we aim to provide an overview of indications, techniques, and results of transcatheter options to treat cavopulmonary stenosis, collaterals, impaired lymphatic drainage, and the management of the fenestration, as well as to explore the recent advancements and clinical applications of transcatheter cavopulmonary connections, percutaneous valvular treatments, and to discuss the future perspectives of percutaneous therapies in the Fontan population.

Transcatheter Dynamic Contrast-Enhanced MR Lymphangiography for Nontraumatic Lymphatic Disorders: Technical Feasibility and Imaging Findings

This study aimed to evaluate the feasibility and added value of transcatheter dynamic contrast-enhanced magnetic resonance (MR) lymphangiography for nontraumatic lymphatic disorders. Five patients (2 males and 3 females; median age, 16.0 years; range, 3-74 years) who underwent both intranodal and transcatheter dynamic contrast-enhanced MR lymphangiography for suspected nontraumatic lymphatic leakages from June 2017 to January 2020 were included in this retrospective study. The imaging findings of both dynamic contrast-enhanced MR lymphangiography techniques were assessed for the presence of chylolymphatic reflux or direct sign of leakage. Intranodal dynamic contrast-enhanced MR lymphangiography demonstrated chylolymphatic reflux into the thoracic area in 2 patients (40%) but no direct evidence of leakage in any of the 5 patients. Transcatheter dynamic contrast-enhanced MR lymphangiography revealed chylolymphatic reflux and extravasation of the contrast agent in all 5 patients (100%). In conclusion, transcatheter dynamic contrast-enhanced MR lymphangiography may reveal additional signs of reflux and extravasation even when the findings of intranodal dynamic contrast-enhanced MR lymphangiography are negative.

Emerging contrast-enhanced ultrasound applications in children

Ultrasound contrast agent (UCA) use in radiology is expanding beyond traditional applications such as evaluation of liver lesions, vesicoureteral reflux and echocardiography. Among emerging techniques, 3-D and 4-D contrast-enhanced ultrasound (CEUS) imaging have demonstrated potential in enhancing the accuracy of voiding urosonography and are ready for wider clinical adoption. US contrast-based lymphatic imaging has been implemented for guiding needle placement in MR lymphangiography in children. In adults, intraoperative CEUS imaging has improved diagnosis and assisted surgical management in tumor resection, and its translation to pediatric brain tumor surgery is imminent. Because of growing interest in precision medicine, targeted US molecular imaging is a topic of active preclinical research and early stage clinical translation. Finally, an exciting new development in the application of UCA is in the field of localized drug delivery and release, with a particular emphasis on treating aggressive brain tumors. Under the appropriate acoustic settings, UCA can reversibly open the blood-brain barrier, allowing drug delivery into the brain. The aim of this article is to review the emerging CEUS applications and provide evidence regarding the feasibility of these applications for clinical implementation.

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.

Intranodal CT Lymphangiography with Water-soluble Iodinated Contrast Medium for Imaging of the Central Lymphatic System

Background Dynamic contrast-enhanced MR lymphangiography (DCMRL) is the reference standard used to diagnose various thoracic lymphatic disorders, such as traumatic chylothorax and plastic bronchitis. However, accessibility and logistical challenges have prevented the wide dissemination of this technology. Purpose To evaluate the feasibility of intranodal CT lymphangiography (ICTL) in the diagnosis and planning of subsequent intervention in patients with thoracic lymphatic disorders. Materials and Methods In this retrospective review, five women suspected of having lymphatic abnormalities (ranging from traumatic chylothorax to plastic bronchitis) and with contraindications to MRI underwent ICTL from September 2019 to May 2020. Needles (25 gauge) were placed in the bilateral inguinal lymph nodes with US guidance, and water-soluble iodinated contrast material was injected. CT fluoroscopy was used to monitor the opacification of the cisterna chyli to determine the timing of CT. After ICTL, the thoracic duct was catheterized, and lymphangiography was performed through the thoracic duct catheter. The ICTL and subsequent lymphangiographic findings were then visually compared by using three-dimensional reconstructions. Results Intranodal injection of water-soluble contrast medium was successful in all patients evaluated (five women; mean age, 68 years ± 11 [standard deviation]; range, 53-83 years). The central lymphatics were opacified in four of the five women, demonstrating abnormal pulmonary lymphatic flow from the thoracic duct into the lung parenchyma. In one of the five women, thoracic duct injection showed successful ligation of the thoracic duct. The time elapsed from injection of contrast medium to visualization of the thoracic duct ranged from 2 to 27 minutes. ICTL and lymphangiographic findings matched well. Conclusion Intranodal CT lymphangiography sufficiently depicted central lymphatic anatomy in patients with lymphatic abnormalities, thereby demonstrating its use as a feasible alternative to more technically challenging methods, such as dynamic contrast-enhanced MR lymphangiography. © RSNA, 2021.

Development and physiological functions of the lymphatic system: insights from human genetic studies of primary lymphedema

Primary lymphedema is a long-term (chronic) condition characterized by tissue lymph retention and swelling that can affect any part of the body, although it usually develops in the arms or legs. Due to the relevant contribution of the lymphatic system to human physiology, while this review mainly focuses on the clinical and physiological aspects related to the regulation of fluid homeostasis and edema, clinicians need to know that the impact of lymphatic dysfunction with a genetic origin can be wide ranging. Lymphatic dysfunction can affect immune function so leading to infection; it can influence cancer development and spread, and it can determine fat transport so impacting on nutrition and obesity. Genetic studies and the development of imaging techniques for the assessment of lymphatic function have enabled the recognition of primary lymphedema as a heterogenic condition in terms of genetic causes and disease mechanisms. In this review, the known biological functions of several genes crucial to the development and function of the lymphatic system are used as a basis for understanding normal lymphatic biology. The disease conditions originating from mutations in these genes are discussed together with a detailed clinical description of the phenotype and the up-to-date knowledge in terms of disease mechanisms acquired from in vitro and in vivo research models.

The Case of a 15-Year-Old With Non-Parasitic Chyluria

Chyluria is defined by the presence of chyle in urine, and is caused by a communication between the lymphatic and urinary system. Commonly, it is characterised by the excretion of milky white urine, which is present in up to 70% of chyluria cases. The prevalent cause for chyluria in Asia is filariasis with Wuchereria bancrofti. Non-parasitic chyluria is more common in western countries and is usually subsequent to traumatic factors, infections, or tumours. The occurrence of non-parasitic chyluria in the absence of trauma, iatrogenic or other, is exceedingly rare. The lymphatic system is rather challenging to visualize. Herein, we present a case of non-parasitic chyluria and our approach of combining different complementing imaging modalities, such as contrast-enhanced ultrasound (CEUS) retrograde pyelography and magnetic resonance (MR) lymphography.

Oncologic Imaging of the Lymphatic System: Current Perspective with Multi-Modality Imaging and New Horizon

The lymphatic system is an anatomically complex vascular network that is responsible for interstitial fluid homeostasis, transport of large interstitial particles and cells, immunity, and lipid absorption in the gastrointestinal tract. This network of specially adapted vessels and lymphoid tissue provides a major pathway for metastatic spread. Many malignancies produce vascular endothelial factors that induce tumoral and peritumoral lymphangiogenesis, increasing the likelihood for lymphatic spread. Radiologic evaluation for disease staging is the cornerstone of oncologic patient treatment and management. Multiple imaging modalities are available to access both local and distant metastasis. In this manuscript, we review the anatomy, physiology, and imaging of the lymphatic system.

The Update of Treatment for Primary Intestinal Lymphangiectasia

Intestinal lymphangiectasia is a rare disease which is causing protein-losing enteropathy. Treatment of intestinal lymphangiectasia can be a challenge for clinicians because of the lack of specific guidelines regarding pharmacological indications. We sought to introduce a diagnostic approach and suggest guidelines for treatment. After exclusion of secondary intestinal lymphangiectasia, magnetic resonance lymphangiography is a promising tool for the assessment of abnormal lymphatic lesions in primary intestinal lymphangiectasia. Determining the extent of the lesion provides direction for treatment options. Focal short-segment intestinal lymphangiectasia can be treated via intestinal resection or radiologic embolization after dietary therapy failure. Diffuse intestinal lymphangiectasia and extensive lymphangiectasia should be treated with several drugs with a full understanding of their mechanisms.

Reaching consensus for unified medical language in Fontan care

Aims

The Fontan operation has resulted in improved survival in patients with single‐ventricle congenital heart disease. As a result, there is a growing population of teenagers and adults with a Fontan circulation. Many co‐morbidities have been increasingly recognized in this population due to the unique features of the Fontan circulation. Standardization of how Fontan co‐morbid conditions are defined will help facilitate understanding, consistency and interpretability of research and clinical experience. Unifying common language usage in Fontan is a critical precursor step for data comparison of research findings and clinical outcomes and ultimately accelerating improvements in management for this growing group of patients. This manuscript aimed to create unified definitions for morbidities seen after the Fontan palliation.

Methods

In association of many congenital heart disease organizations, this work used Delphi methodology to reach a broad consensus among recognized experts regarding commonly used terms in Fontan care and research. Each definition underwent at least three rounds of revisions to reach a final definition through surveys sent to experts in the field of single‐ventricle care.

Results

The process of reaching a consensus on multiple morbidities associated with the Fontan procedure is summarized in this manuscript. The different versions that preceded reaching the consensus are also presented in the Supporting Information. Table 1 represents the final definitions according to the consensus.

Conclusions

We propose the use of these definitions for clinical care, future research studies, registry development and clinical trials.