Dynamic Contrast-enhanced Magnetic Resonance Lymphangiography Research Articles

MR Lymphangiography: Congenital Lymphatic Flow Disorders.

Congenital lymphatic flow disorders collectively refer to a heterogeneous group of diseases that manifest as chylothorax, chylous ascites, intestinal lymphangiectasia, protein-losing enteropathy, and peripheral extremity or genital lymphedema, all in the absence of identifiable injury to the lymphatic system. We have only recently begun to understand congenital lymphatic flow disorders through the ability to image lymph flow dynamically. Intranodal dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) is a crucial technique for imaging lymphatic flow in pediatric patients with congenital lymphatic flow disorders. However, as lymphatic imaging is still a nascent discipline with many uncertainties regarding optimal imaging and treatment, effective patient management requires a comprehensive understanding of imaging techniques, disease pathophysiology, and multidisciplinary treatment approaches. Above all, a fundamental understanding of the physiological lymphatic flow of the central conducting lymphatics is essential for the correct interpretation of DCMRL images. This knowledge helps to avoid unnecessary examinations, erroneous diagnoses, and potentially harmful treatment approaches. This review provides an overview of the methods, advantages, and precautions for interpreting the DCMRL examination, a state-of-the-art lymphatic system imaging technique, and shares various case studies.

Single-Center Experience With Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography for Diagnosing Lymphatic Disorders and Guiding Percutaneous Embolization.

The pragmatic role of dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) needs to be evaluated and compared across distinct lymphatic disorders. We aimed to evaluate the performance of DCMRL for identifying the underlying causes of lymphatic disorders and to define the potential benefit of DCMRL for planning lymphatic interventions. Patients who underwent DCMRL between August 2017 and July 2022 were included in this retrospective analysis. DCMRL was performed with intranodal injection of a gadolinium-based contrast medium through inguinal lymph nodes under local anesthesia. Technical success of DCMRL and feasibility of percutaneous embolization were assessed based on the lymphatic anatomy visualized by DCMRL. Based on the underlying causes, clinical outcomes were evaluated and compared. Seventy consecutive patients were included. The indications were traumatic chylothorax (n = 42), traumatic chylous ascites (n = 11), and nontraumatic lymphatic leak (n = 17). The technical success rate of DCMRL was the highest in association with nontraumatic lymphatic disorders (94.1% [16/17]), followed by traumatic chylothorax (92.9% [39/42]) and traumatic chylous ascites (81.8% [9/11]). Thirty-one (47.7%) patients among 65 patients who underwent technically successful DCMRL had feasible anatomy for intervention. Clinical success was achieved in 90.3% (28/31) of patients with feasible anatomy for radiologic intervention, while 62.5% (10/16) of patients with anatomical challenges showed improvement. Most patients with traumatic chylothorax showed improvement (92.9% [39/42]), whereas only 23.5% (4/17) of patients with nontraumatic lymphatic disorders showed clinical improvement. DCMRL can help identify the underlying causes of lymphatic disorders. The performance of DCMRL and clinical outcomes vary based on the underlying cause. The feasibility of lymphatic intervention can be determined using DCMRL, which can help in predicting clinical outcomes.

Massive Chylous Ascites in a 9-Year-Old Girl with Malrotation-A Case Report.

Malrotation leading to massive chylous ascites is rare. A 9-year-old girl was investigated for slowly increasing abdominal distension under a year. She had no vomiting, weight loss, or pain, but was bothered in social situations. Medical investigations, including ultrasound and computed tomography scans, revealed massive ascites. Laparocentesis yielded milk-colored fluid, confirmed as lymph through laboratory analysis. A complete blood count, liver function and hematologic parameters, chyle cytology, bacterial cultures, and polymerase chain reaction for tuberculosis were all within normal limits. She was referred to a tertiary center for vascular anomalies. A dynamic contrast-enhanced magnetic resonance lymphangiography showed normal lymphatic anatomy without leakage or flow obstruction. A whole-body magnetic resonance imaging revealed a central mesenteric rotation. She was referred to a tertiary center for pediatric surgery, where a laparoscopic Ladd's procedure was performed using a new 5 mm pediatric sealing device, along with an appendectomy using a 5 mm stapler. To derotate the bowel, fenestrations were created in compartments containing a substantial amount of chyle and ascites, resulting in the drainage of 2.4 L of fluid. She was discharged the day after surgery and has been in good health for 1 year. We present a video illustrating the Ladd's procedure steps in this patient.

Feasibility of contrast-enhanced ultrasound in confirming intranodal needle position for dynamic contrast-enhanced magnetic resonance lymphangiography in children.

This report demonstrates the feasibility and safety of using contrast-enhanced ultrasound (CEUS) to confirm intranodal needle position in children requiring dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL). A total of 7 patients were evaluated using CEUS after nodal puncture on a detachable magenetic resonance table, with 2 nodes cannulated in each patient, resulting in a combined evaluation of 14 nodes. The nodal cannulation success rate using CEUS was 85.7% (12/14 nodes). DCMRL was performed successfully in all patients with good contrast opacification of the central conducting lymphatics. Out of the 14 nodes, 2 nodes in the same patient demonstrated persistent extravasation on CEUS despite needle readjustment, requiring conversion to fluoroscopic lymphangiography. No adverse event related to the injection technique or CEUS was reported.

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

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

Evaluation of Chylothorax Using Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography After Lung Cancer Surgery.

Background: To determine the role of dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) in the management of postoperative chylothorax after lung cancer surgery. Methods and Results: Between July 2017 and November 2021, patients who developed postoperative chylothorax following pulmonary resection and mediastinal lymph node dissection were assessed and those who underwent DCMRL for the evaluation of chyle leak were evaluated. The findings of DCMRL and conventional lymphangiography were compared. The incidence of postoperative chylothorax was 0.9% (50/5587). Among the patients with chylothorax, a total of 22 patients (44.0% [22/50]; mean age, 67.6 ± 7.9 years; 15 men) underwent DCMRL. Treatment outcomes were compared between patients with conservative management (n = 10) and those with intervention (n = 12). The patients demonstrated unilateral pleural effusion, ipsilateral to the operation site, and showed right-sided dominance. The most frequent site of thoracic duct injury showing contrast media leakage was visualized at the subcarinal level. No DCMRL-related complication occurred. DCMRL showed comparable performance to conventional lymphangiography in visualizing the central lymphatics, including cisterna chyli (DCMRL vs. conventional lymphangiography, 72.7% vs. 45.5%, p = 0.25) and thoracic duct (90.9% vs. 54.5%, p = 0.13), and in localizing thoracic duct injury (90.9% vs. 54.5%, p = 0.13). On follow-up, the amount of chest tube drainage after lymphatic intervention showed a significant difference over time from that after medical treatment only (p = 0.02). Conclusion: DCMRL can provide detailed information about the leak site and the central lymphatic anatomy in patients with chylothorax after lung cancer surgery. The findings of DCMRL can guide subsequent treatment planning for optimal outcomes.

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

To evaluate the feasibility and image quality of intranodal dynamic contrast-enhanced CT lymphangiography (DCCTL) and dynamic contrast-enhanced MR lymphangiography (DCMRL) in microminipigs. Our institution's committee for animal research and welfare provided approval. Three microminipigs underwent DCCTL and DCMRL after inguinal lymph node injection of 0.1mL/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. The CEI peaked at 5-10min in all microminipigs. The SIR peaked at 2-4min in two microminipigs and at 4-10min 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. 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. • Intranodal dynamic contrast-enhanced computed tomography lymphangiography showed a contrast enhancement peak at 5-10min in all microminipigs. • Intranodal dynamic contrast-enhanced magnetic resonance lymphangiography showed a contrast enhancement peak at 2-4min in two microminipigs and at 4-10min 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.

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.

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.

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.

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.

Intrahepatic Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography: Potential Imaging Signature for Protein-Losing Enteropathy in Congenital Heart Disease.

BackgroundProtein‐losing enteropathy (PLE) is a significant cause of morbidity and mortality in congenital heart disease patients with single ventricle physiology. Intrahepatic dynamic contrast‐enhanced magnetic resonance lymphangiography (IH‐DCMRL) is a novel diagnostic technique that may be useful in characterizing pathologic abdominal lymphatic flow in the congenital heart disease population and in diagnosing PLE. The objective of this study was to characterize differences in IH‐DCMRL findings in patients with single ventricle congenital heart disease with and without PLE.Methods and ResultsThis was a single‐center retrospective study of IH‐DCMRL findings and clinical data in 41 consecutive patients, 20 with PLE and 21 without PLE, with single ventricle physiology referred for lymphatic evaluation. There were 3 distinct duodenal imaging patterns by IH‐DCMRL: (1) enhancement of the duodenal wall with leakage into the lumen, (2) enhancement of the duodenal wall without leakage into the lumen, and (3) no duodenal involvement. Patients with PLE were more likely to have duodenal involvement on IH‐DCMRL than patients without PLE (P<0.001).ConclusionsIH‐DCMRL findings of lymphatic enhancement of the duodenal wall and leakage of lymph into the duodenal lumen are associated with PLE. IH‐DCMRL is a useful new modality for characterizing pathologic abdominal lymphatic flow in PLE and might be useful as a risk‐assessment tool for PLE in at‐risk patients.

Abnormal Pulmonary Lymphatic Flow on Novel Lymphangiographic Imaging Supports a Common Etiology of Lymphatic Plastic Bronchitis and Nontraumatic Chylothorax.

Background: This study evaluates whether dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) and thoracic duct lymphangiography (TDL) findings in adults with lymphatic plastic bronchitis (PB) and/or nontraumatic chylothorax (NTC) support a shared pathophysiology. Materials and Results: Retrospective review of clinical and imaging findings in patients who underwent DCMRL and TDL at a single institution from March 2017 to March 2019. Categorical variables were compared with Fisher's exact test. Twenty-eight patients (median age 61 ± 21 years, 15 women) presenting with lymphatic PB (n = 13), NTC (n = 10), or both (n = 5) were included. Lymphatic imaging demonstrated pulmonary lymphatic perfusion (PLP) in all patients. A patent thoracic duct (TD) with retrograde flow was seen in 53.4% (7/13) of patients with PB, 60% (6/10) of patients with NTC, and 20% (1/5) of patients with both (p = 0.69). An occluded TD with retrograde flow was seen in 30.8% (4/13) of patients with PB, 30% (3/10) of patients with NTC, and 80% (4/5) of patients with both (p = 0.12). Similar patterns of PLP between DCMRL and TDL were seen in 96.2% (25/26) of patients. Conclusions: DCMRL and TDL demonstrated similar findings in patients with lymphatic PB and/or NTC, supporting a common etiology. This supports the hypothesis that the clinical presentation depends on the proximity of abnormal lymphatic vessels to the pleural cavity, resulting in chylothorax, or bronchial mucosa, resulting in PB.

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.

Dynamic contrast-enhanced magnetic resonance lymphangiography in pediatric patients with central lymphatic system disorders.

Central conducting lymphatics (CCLs) disorders represent a broad spectrum of clinical entities ranging from self-limiting traumatic leaks treated by conservative strategies, to complex lymphatic circulation abnormalities that are progressive and unresponsive to currently available treatments. Dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) performed by intranodal injection of gadolinium-based contrast material is a recently developed technique which allows a minimally invasive evaluation of the CCL abnormalities providing a dynamic assessment of lymph flow and its pathways. In our institution, DCMRL is performed after bilateral cannulation of inguinal lymph nodes, using a MR protocol which includes volumetric 3D T2-SPACE (sampling perfection with application-optimized contrasts using different flip-angle evolution) and free-breathing respiratory navigated sequence and TWIST (time-resolved angiography with Interleaved stochastic trajectories) MR angiography sequence, during intranodal injection of paramagnetic contrast medium. Although DCMRL applications in clinical practice are still improving, a minimally invasive assessment of lymphatic pathways is particularly important both in pediatric patients with primitive lymphatic system disorders and in children with complex congenital heart disease associated with CCL impairment.

Pediatric Lymphatics Review: Current State and Future Directions.

Pediatric lymphatic flow disorders present a unique disease spectrum with specific challenges and considerations. The immense recent advances in lymphatic imaging and therapeutics have allowed the identification and treatment of these devastating symptoms from the neonatal period to adolescence. The development of dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) has provided accurate diagnoses and classification of neonatal and pediatric flow disorders. The concomitant innovation in the field of lymphatic interventions including thoracic duct (TD) embolization, interstitial embolization, and lymphovenous anastomosis offers curative interventions. As the field rapidly grows, there is a need for both classification and treatment algorithms for these diseases.

Abnormal Pulmonary Lymphatic Flow in Patients With Lymphatic Anomalies and Respiratory Compromise

Pulmonary involvement in lymphatic anomalies (LA) is associated with significant morbidity and mortality. Dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) is capable of imaging the lymphatic system in a variety of pulmonary lymphatic disorders. The objective of this study is to describe the central lymphatic anatomy in patients with LA and pulmonary involvement on DCMRL. This prospective observational study enrolled 16 patients with LA (mean age, 17 years; range, 6-63 years; ratio of female to male patients, 9:7) with pulmonary involvement. All patients underwent DCMRL. The lymphatic system was assessed for the presence of mediastinal masses, interstitial lung disease, size and tortuosity of the thoracic duct (TD), and presence of abnormal pulmonary lymphatic flow. T2-weighted imaging showed the following: mediastinal soft tissue masses in 10 patients, diffuse pulmonary interstitial thickening in 13 patients, and bone involvement in 15 patients. DCMRL revealed abnormal pulmonary lymphatic flow in 14 of 16 patients. Abnormal pulmonary lymphatic flow originated from the TD in three of 14 patients, the retroperitoneum in six of 14 patients, and both the TD and retroperitoneum in four of 14 patients. In nine of 16 patients, the TD was dilated and tortuous. In two patients the TD was not identified, and in five patients it was normal. Abnormal pulmonary lymphatic flow/perfusion from the TD or retroperitoneum into the lung parenchyma occurred in the majority of patients in this study. These findings can explain the interstitial lung disease and chylothorax resulting in deterioration of respiratory function in these patients. Future studies will determine whether mechanical cessation of this abnormal flow can improve pulmonary function and prolong survival in patients with LA. Clinicaltrials.gov; No.: NCT02744027; URL: www.clinicaltrials.gov.

Successful Percutaneous Lymphatic Intervention for Chylothorax after Pediatric Heart Transplantation

Purpose Chylothorax after pediatric heart transplantation (HTX) is a highly morbid and challenging disease often refractory to therapies including thoracic duct ligation or pleurodesis. We report our novel approach to lymphatic imaging and percutaneous intervention for chylothorax after HTx in children. Methods We reviewed our center's data on children with post-HTx chylothorax who underwent dynamic contrast-enhanced magnetic resonance lymphangiography (DCRL) and lymphatic embolization between November 2014 and November 2017. Results Four children (50% male, median age 5 ± 45 months) were referred for post-HTx chylothorax. Three underwent HTx for congenital heart disease (including 1 single ventricle) and 1 for dilated cardiomyopathy. Three had chylothorax immediately post-HTx associated with superior caval anastomosis obstruction or diastolic dysfunction and 1 developed chylothorax 6 months post-HTx during antibody-mediated rejection. Lymphatic imaging demonstrated abnormal pulmonary lymphatic perfusion syndrome in all 4 patients, with percutaneous interventions performed including thoracic duct or channel embolization (Figure: right - fluoroscopic image of contrast injected into thoracic duct; left - DCMRL inguinal lymph node injection; arrow highlight abnormal pulmonary perfusion; arrowhead identify thoracic duct). All 4 patients with chylothorax had complete resolution with a median 6.5 days from intervention to chest tube removal. Conclusion Chylothorax after pediatric HTx may result from abnormal pulmonary lymphatic perfusion that can be successfully treated with percutaneous lymphatic embolization. Factors associated with pulmonary lymphatic diseases after pediatric HTx include congenital heart disease and elevated central venous pressure due to SVC obstruction or rejection-mediated diastolic dysfunction. Chylothorax after pediatric heart transplantation (HTX) is a highly morbid and challenging disease often refractory to therapies including thoracic duct ligation or pleurodesis. We report our novel approach to lymphatic imaging and percutaneous intervention for chylothorax after HTx in children. We reviewed our center's data on children with post-HTx chylothorax who underwent dynamic contrast-enhanced magnetic resonance lymphangiography (DCRL) and lymphatic embolization between November 2014 and November 2017. Four children (50% male, median age 5 ± 45 months) were referred for post-HTx chylothorax. Three underwent HTx for congenital heart disease (including 1 single ventricle) and 1 for dilated cardiomyopathy. Three had chylothorax immediately post-HTx associated with superior caval anastomosis obstruction or diastolic dysfunction and 1 developed chylothorax 6 months post-HTx during antibody-mediated rejection. Lymphatic imaging demonstrated abnormal pulmonary lymphatic perfusion syndrome in all 4 patients, with percutaneous interventions performed including thoracic duct or channel embolization (Figure: right - fluoroscopic image of contrast injected into thoracic duct; left - DCMRL inguinal lymph node injection; arrow highlight abnormal pulmonary perfusion; arrowhead identify thoracic duct). All 4 patients with chylothorax had complete resolution with a median 6.5 days from intervention to chest tube removal. Chylothorax after pediatric HTx may result from abnormal pulmonary lymphatic perfusion that can be successfully treated with percutaneous lymphatic embolization. Factors associated with pulmonary lymphatic diseases after pediatric HTx include congenital heart disease and elevated central venous pressure due to SVC obstruction or rejection-mediated diastolic dysfunction.

Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography and Percutaneous Lymphatic Embolization for the Diagnosis and Treatment of Recurrent Chyloptysis

Chyloptysis, or the expectoration of triglyceride-rich sputum, is rare and typically treated with diet modification and thoracic duct ligation. This article describes 2 patients with prolonged histories of chyloptysis who failed conservative treatment and thoracic duct ligation. Dynamic contrast-enhanced magnetic resonance imaging delineated the lymphatic anatomy and identified the abnormal pulmonary lymphatic perfusion pathways in both patients. This imaging provided guidance for successful percutaneous lymphatic embolization which resulted in resolution of symptoms in both patients.

Lymphatic dysfunction in critical illness.

The essential role of the lymphatic system in fluid homeostasis, nutrient transport, and immune trafficking is well recognized; however, there is limited understanding of the mechanisms that regulate lymphatic function, particularly in the setting of critical illness. The lymphatics likely affect disease severity and progression in every condition, from severe systemic inflammatory states to respiratory failure. Here, we review structural and functional disorders of the lymphatic system, both congenital and acquired, as they relate to care of the pediatric patient in the intensive care setting, including novel areas of research into medical and procedural therapeutic interventions. The mainstay of current therapies for congenital and acquired lymphatic abnormalities has involved nonspecific medical management or surgical procedures to obstruct or divert lymphatic flow. With the development of dynamic contrast-enhanced magnetic resonance lymphangiography, image-directed percutaneous intervention may largely replace surgery. Because of new insights into the mechanisms that regulate lymphatic biology, pharmacologic inhibitors of mTOR and leukotriene B4 signaling are each in Phase II clinical trials to treat abnormal lymphatic structure and function, respectively. As our understanding of normal lymphatic biology continues to advance, we will be able to develop novel strategies to support and augment lymphatic function during critical illness and through convalescence.