Imaging of Lymphatic Anomalies

Following completion of the T2 lymphatic mapping, contrast agent administered will be calculated based on weight. Investigators will use dosage of 0.1cc/kg of contrast which will be injected by hand simultaneously into each lymphatic node (LN) at a rate of 0.5-1 cc per min. One minute after the injection, scanning will be initiated using high spatial and temporal resolution magnetic resonance angiography (syngo time-resolved angiography with stochastic trajectories \[TWIST\]) sequence. The sequence parameters will be adjusted with a time delay such that a complete volume will be acquired approximately every 20-60 seconds. This will be followed by additional scans with a high-resolution navigator gated 3-dimensional flash inversion recovery (IR) sequence. In all subjects the scan area covered the neck, chest, and abdomen as caudal as feasible.

Magnetic Resonance imaging (MRI) will be performed and T2W MRI lymphatic mapping will be performed using a respiratory navigated and cardiac gated 3 dimensional turbo spin echo sequence with pre-set parameters. Scan time varies from 2-5 min depending upon the size of the subject.

"The procedure will be performed under sedation and anesthesia if participants are aged 16 or under. The procedure will be performed with local anesthesia for participants aged over 16 years old.~Using ultrasound guidance two inguinal lymph nodes (one each side) will be directly accessed with 25-gauge spinal needles attached to a short connector tubing. A shallow angle for puncture will be used to create a long subcutaneous tract to assist in stabilizing the needle. A small amount of an oil-based contrast or water soluble contrast will be injected under fluoroscopy guidance to confirm the correct position of the needles inside the lymph nodes. After stabilizing the needle, the subjects will be transferred into the MRI suite."