Imaging Findings of Thoracic Lymphatic Abnormalities

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.

The value of MRI in the diagnosis of pediatric head and neck lymphatic malformations: A study of 46 surgical cases

Objective To discuss the value of MRI in diagnosing and evaluating the pediatric head and neck lymphatic malformations (HNLMs). Methods We performed a retrospective review of 46 children who were referred to our hospital in the last decade for the treatment of HNLMs. Results About 34 cases confirmed with intralesional hemorrhage while the capsule contents were dark red or light bloody liquid. The remaining 12 pure HNLMs were filled with yellow clear or watery liquid. The multilocular HNLMs accounted for 95.7 % (44/46). The accuracy of contrast enhanced MRI (CE-MRI) diagnosis of HNLMs was 100 %. On MRI, the HNLMs appeared as irregular shape [95.7 % (44/46)], clear boundary [91.3 % (42/46)], infiltrative growth [91.3 % (42/46)] cystic masses. The cystic wall and septa were hyperintense on T1WI and hypointense on T2WI (100 %), and displayed enhancement. The capsule contents had hypointense on T1WI and hyperintense on T2WI in 18 cases (pure HNLMs,12; intracystic hemorrhage,6), while that of mixed signal in 28 cases (pure HNLMs,0; intracystic hemorrhage,28). Capsule contents were enhanced in 22 cases (pure HNLMs,1; intracystic hemorrhage,21), while the remaining 24 without enhancement (pure HNLMs,11; intracystic hemorrhage,13). Liquid-liquid levers were found in 21 cases (pure HNLMs,0; intracystic hemorrhage,21). There were statistical differences in capsule contents signal, enhancement, and liquid-liquid levels between the two groups (P < 0.05). Conclusions On MRI, HNLMs typically show a thin-walled, well-circumscribed, irregularly shaped, infiltrative, unenhanced, multilocular cystic mass with hypointense on T1WI and hyperintense on T2WI. The capsule wall and septa are hyperintense on T1WI, hypointense on T2WI, and display enhancement. Changes in the signal of capsule contents or appearance of liquid-liquid levels indicate intracystic hemorrhage.

Refractory chylothorax after severe vomiting and coughing in a 4-year-old child

Chylothorax is the accumulation of lymphatic fluid in the pleural space. It is a rare condition with potentially life-threatening disorders. In children, the etiology of chylothorax can be mainly attributed to idiopathic factors, congenital, miscellaneous, trauma and malignancies. Conservative treatments can solve most chylothorax, but refractory chylothorax can be challenging to manage. We herein present the case of a 4-year-old girl with no previous medical history who was admitted to our institution after severe vomiting and right chylothorax. The etiological assessment could not identify specific causes. Initial treatment was conservative but after 14 days, the patient showed no improvement. An exploratory thoracoscopy using indocyanine green showed no active leaks. Pleurodesis was performed and, later on, ligation of the ductus thoracicus. Hereafter, the patient progressed favorably. Even though conservative treatments of chylothorax show a high success rate, the efficacy of additional therapies and the benefits between surgical procedures need further investigation.