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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., Competing Interests: Conflicts of Interest The authors declare they have no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

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.

Objectives: To characterize hepatic to systemic lymphatic connections in patients with systemic lymphatic disease using intra-hepatic lymphangiography and to compare outcomes after lymphatic intervention., Methods: In this retrospective study, patients with intra-hepatic lymphangiography from May 2014 - April 2019 at our institution were included. Imaging review was performed and hepatic lymphatic connections and flow patterns were characterized. Clinical data were reviewed and comparisons between patients undergoing lymphatic intervention with or without abnormal hepatic lymphatics were performed., Results: During the study period, 105 patients underwent intra-hepatic lymphangiography. Primary clinical presentation included ascites (19/105), chylothorax (27/105), plastic bronchitis (PB) (17/105), and protein losing enteropathy (PLE) (42/105). Five categories of hepatic lymphatic connections and flow patterns were identified (%): normal (25%, 26/105), hepatoperitoneal (12%, 13/105), hepatopulmonary (10.5%, 11/105), hepatomesenteric (7.5%, 8/105), and hepatoduodenal (41%, 43/105) with four patients having more than one abnormal pattern. A comparison between clinical presentation and imaging category revealed an increased likelihood of having ascites with hepatoperitoneal (p < .0001), chylothorax/PB with hepatopulmonary (p = .01), and PLE with hepatoduodenal (p < .001) connections. Seventy-six patients had a lymphatic intervention, 24% with normal, and 76% with abnormal liver lymphatics. There was no difference in length of hospital stay or mortality between the two groups, but there was a prolonged time to symptom resolution (p = .006) and persistent symptoms after 6 months (5% vs 44%, p = .002) in the group with abnormal liver lymphatics., Conclusion: We identified five liver lymphatic imaging categories with a substantial correlation to presenting lymphatic disease. Abnormal imaging patterns correlated with increased morbidity. Evaluation of liver lymphatics should be considered in patients with a systemic lymphatic disease if central lymphatic imaging is normal., Key Points: • We identified five liver lymphatic imaging patterns: normal, hepatoperitoneal, hepatomesenteric, hepatopulmonary, and hepatoduodenal. • Imaging patterns were correlated with disease presentation (normal - chylothorax/PB, hepatoperitoneal - ascites/chylothorax, hepatopulmonary - chylothorax/PB, hepatoduodenal - PLE). • Abnormal imaging patterns correlated with increased morbidity., (© 2021. The Author(s).)

Lymphangiectasias are lymphatic malformations characterized by the abnormal dilation and morphology of the lymphatic channels. The classification and treatment of these disorders can be challenging given the limited amount of literature available in children. Various imaging modalities are used to confirm suspected diagnosis, plan the most appropriate treatment, and estimate a prognosis. Prenatal evaluation is performed using both prenatal US imaging and fetal MRI. These modalities are paramount for appropriate parental counseling and planning of perinatal care. During the neonatal period, chest US imaging is a useful modality to evaluate pulmonary lymphangiectasia because other modalities such as conventional radiography and CT display nonspecific findings. Finally, the recent breakthroughs in lymphatic imaging with MRI have allowed us to better classify lymphatic disorders. Dynamic contrast-enhanced lymphangiography, conventional lymphangiography and percutaneous lymphatic procedures offer static and dynamic evaluation of the central conducting lymphatics in children, with excellent spatial resolution and the possibility to provide treatment. The purpose of this review is to discuss the normal and abnormal development of the fetal lymphatic system and how to best depict it by imaging during the prenatal and postnatal life.

The aim of this study was to determine the feasibility of using contrast-enhanced ultrasound (CEUS) evaluation to determine thoracic duct (TD) outlet patency. Nine patients referred for lymphatic imaging and intervention underwent percutaneous intranodal ultrasound contrast injection and conventional lymphangiography (CL). Eight of 9 patients had a patent TD by CEUS and CL. One patient did not have a patent TD. There was 100% agreement between CEUS and CL. These results suggest that CEUS is an imaging modality that might be as accurate as CL in determining TD patency., (Copyright © 2020 SIR. Published by Elsevier Inc. All rights reserved.)

Background Recent studies suggest that lymphatic congestion plays a role in development of late Fontan complications, such as protein-losing enteropathy. However, the role of the lymphatic circulation in early post-Fontan outcomes is not well defined. Methods and Results This was a retrospective, single-center study of patients undergoing first-time Fontan completion from 2012 to 2017. The primary outcome was early Fontan complication ≤6 months after surgery, a composite of death, Fontan takedown, extracorporeal membrane oxygenation, chest tube drainage >14 days, cardiac catheterization, readmission, or transplant. Complication causes were assigned to 1 of 4 groups: (1) Fontan circuit obstruction, (2) ventricular dysfunction or atrioventricular valve regurgitation, (3) persistent pleural effusions in the absence of Fontan obstruction or ventricular dysfunction, and (4) chylothorax or plastic bronchitis. T2-weighted magnetic resonance imaging sequences were used to assess for lymphatic perfusion abnormality. The cohort consisted of 238 patients. Fifty-eight (24%) developed early complications: 20 of 58 (34.5%) in group 1, 8 of 58 (14%) in group 2, 18 of 58 (31%) in group 3, and 12 of 58 (20%) in group 4. Preoperative T2 imaging was available for 126 (53%) patients. Patients with high-grade lymphatic abnormalities had 6 times greater odds of developing early complications ( P =0.001). Conclusions There is substantial morbidity in the early post-Fontan period. Half of those who developed early complications had lymphatic failure or persistent effusions unrelated to structural or functional abnormalities. Preoperative T2 imaging demonstrated that patients with higher-grade lymphatic perfusion abnormalities were significantly more likely to develop early complications. This has implications for risk stratification and optimization of patients before Fontan palliation.

Objectives: To describe the technique and report on our initial experience with the use of intrahepatic dynamic contrast magnetic resonance lymphangiography (IH-DCMRL) for evaluation of the lymphatics in patients with hepatic lymphatic flow disorders., Methods: This is a retrospective review of the imaging and clinical findings in six consecutive patients undergoing IH-DCMRL. The technique involves injection of a gadolinium contrast agent into the intrahepatic lymphatic ducts followed by imaging of the abdomen and chest with both heavily T2-weighted imaging and dynamic time-resolved imaging., Results: In six consecutive patients, IH-DCMRL was technically successful. There were four patients with protein-losing enteropathy (PLE) and two with ascites in this study. In the four patients with PLE, IH-DCMRL demonstrated hepatoduodenal connections with leak of contrast into the duodenal lumen not seen by conventional lymphangiography. In one patient with ascites, IH-DCMRL demonstrated lymphatic leakage into the peritoneal cavity not seen by intranodal lymphangiography. In the second patient with ascites, retrograde lymphatic perfusion of mesenteric lymphatic networks and nodes was seen. Venous contamination was seen in two patients. No biliary contamination was identified. There were no short-term complications., Conclusions: IH-DCMRL is a cross-sectional technique which successfully evaluated hepatic lymphatic flow disorders and warrants further investigation., Key Points: • Intrahepatic dynamic contrast magnetic resonance lymphangiography (IH-DCMRL) is a new imaging technique to evaluate hepatic lymphatic flow disorders such as protein-losing enteropathy. • In comparison to conventional liver lymphangiography, IH-DCMRL offers a 3D imaging technique and better distal lymphatic contrast distribution and does not use ionizing radiation.

Recent advances in understanding lymphatic disorders have significantly improved noninvasive imaging of the lymphatic circulation, especially in pediatric patients. The ability to obtain high-quality MR imaging using 3-dimensional reconstruction has transformed the display of the lymph vessels and substantially enhanced the ability to diagnose various pediatric lymphatic disorders. Real-time dynamic imaging adds functional information to the assessment. MR imaging is increasingly used, not only to assess but also as a follow-up after lymphatic disorder treatment. This article discusses up-to-date imaging techniques and clinical applications of dynamic magnetic resonance lymphangiography for assessing central conducting lymphatic anomalies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Rationale and Objectives: This study aimed to describe prenatal and postnatal imaging features and outcomes of neonates with neonatal lymphatic disorders (NLDs)., Materials and Methods: An institutional review board-approved search of the radiology database for patients with NLD identified five patients. Inclusion criteria include prenatal imaging (fetal magnetic resonance [MR] imaging and ultrasound) and postnatal three-dimensional T2 Sampling Perfection with Application optimized Contrasts using different flip angle Evolution (SPACE) and dynamic contrast-enhanced MR lymphangiography within 6 months of life. Chart review was undertaken to evaluate morbidity and mortality., Results: Prenatal finding of "nutmeg lung" or fetal pulmonary lymphatic disorder was identified in all five patients on fetal MR imaging, and in four of five patients on fetal ultrasound. Postnatal dynamic contrast-enhanced MR lymphangiography demonstrated abnormal lymphatic flow to the lungs in four of five patients, but absent in the single patient with coexisting hypoplastic left heart syndrome (HLHS). Dermal backflow was seen in one patient, also the only patient with prenatal body wall edema. Three patients with lymphatic flow to the lungs only were classified as neonatal chylothorax. The patient with dermal backflow and perfusion to the lungs was diagnosed with central lymphatic flow disorder (CLFD). The HLHS patient with normal lymphatic perfusion maintained the HLHS diagnosis. Of the five patients, the patient with CLFD and the one with HLHS expired because of respiratory distress., Conclusions: NLDs can be recognized on prenatal and postnatal imaging and may be primary, as in neonatal chylothorax or CLFD, or secondary. In this small series, "nutmeg lung" was present in all patients. Prenatal imaging demonstrates that body wall edema may correlate with postnatal dermal backflow, which, in our small cohort, carried a poor prognosis., (Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Complex lymphatic anomalies are unique diseases marked by abnormal lymphatic vessel development and growth. Imaging is crucial in the evaluation and management of complex lymphatic anomalies, with dynamic contrast-enhanced MR lymphangiography emerging as a valuable modality for visualizing abnormal lymphatic structures and informing treatment decisions. This article gives an overview of complex lymphatic anomalies and their management strategies, focusing specifically on generalized lymphatic anomaly, Gorham-Stout disease, Kaposiform lymphangiomatosis, and central conducting lymphatic anomalies. Simple lymphatic diseases are beyond the scope of this review.Graphical Abstract: Complex lymphatic anomalies are unique diseases marked by abnormal lymphatic vessel development and growth. Imaging is crucial in the evaluation and management of complex lymphatic anomalies, with dynamic contrast-enhanced MR lymphangiography emerging as a valuable modality for visualizing abnormal lymphatic structures and informing treatment decisions. This article gives an overview of complex lymphatic anomalies and their management strategies, focusing specifically on generalized lymphatic anomaly, Gorham-Stout disease, Kaposiform lymphangiomatosis, and central conducting lymphatic anomalies. Simple lymphatic diseases are beyond the scope of this review. [ABSTRACT FROM AUTHOR]