E5056. MR Lymphangiography: Techniques, Insights, and Observations in Postoperative Lymphatic Complications
  1. Rupesh Gautam; University of Texas Health Houston
  2. Varrah Tammisetti; University of Texas Health Houston
  3. Shahin Mohamed; University of Texas Health Houston
  4. Rodrick Zvavanjanja; University of Texas Health Houston
MR lymphangiography has emerged as a potent tool for depicting the details of lymphatic anatomy and the dynamics of lymphatic flow. Although conventional lymphoscintigraphy continues to be employed for evaluating lymphatic disorders in diverse clinical scenarios, it carries drawbacks such as limited spatial resolution, constrained dynamic imaging, exposure to ionizing radiation, and inadequate anatomical visualization. Fluoroscopic examination of the lymphatic system using oil-based contrast agents via intranodal injection is also a commonly used investigative approach. However, it has downsides of radiation exposure and incomplete portrayal of the lymphatic network. MRI in conjunction with T2-weighted imaging offers an advantageous feature of revealing additional nonlymphatic findings that could significantly impact the clinical management of patients.

Educational Goals / Teaching Points
a. Provide a concise overview of the lymphatic system's anatomy. b. Explain the technical aspects involved in MR lymphangiogram. c. List the various applications of MR lymphangiogram, which includes the following. 1. Evaluation of lymphatic malformations. 2. Recognize deviations in the lymphatic channels for guiding interventions. 3. Detect and characterize postoperative leaks. 4. Determine the origin of chylous ascites and chylothorax. d. Case-based exploration and highlighting relevant imaging findings.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
The procedure involved ultrasound-guided intranodal cannulation of bilateral inguinal lymph nodes, after which the patient was transferred to the MR scanner. Precontrast imaging consisted of three planar, heavily T2-weighted, single-shot images and T1 imaging of the chest, abdomen, and pelvis. Subsequently, a gadolinium-based contrast agent diluted in normal saline was injected into the bilateral inguinal lymph nodes. This was followed by acquiring 3D T1-weighted images of the chest, abdomen, and pelvis at 1-minute intervals, up to a duration of 30 minutes. The primary focus of investigations conducted at our institution centered on the assessment of postoperative ascites or chylothorax. Additionally, a subset of MRI studies was undertaken to validate the presence of congenital lymphatic malformations and precise identification of the thoracic duct obstruction. Illustration of these findings will be presented through a collection of MR images in this exhibit.

The optimal modality for investigating lymphatic disorders is MR lymphangiogram, offering distinct advantages, such as absence of radiation exposure, comprehensive assessment of extra lymphatic findings, and precise anatomical delineation.