1356515 - Against all odds: MR lymphatic image guidance of percutaneous lymphatic intervention for plastic bronchitis in a Fontan patient with pacemaker

This is a case of a 7-year-old male with history of hypoplastic left heart syndrome who underwent fenestrated extracardiac conduit Fontan and epicardial pacemaker for sick sinus syndrome at age 3. Post-operatively, he was treated with pulmonary vasodilator therapy due to persistent pericardial and pleural effusions requiring drainage. He was discharged home 6 weeks following his Fontan surgery.

He presented at age 7 with severe hypoxemia and was diagnosed with plastic bronchitis and failing Fontan physiology. A cardiac catheterization on admission showed elevated Fontan pressure (19mmHg) and he required bronchoscopy for removal of a large cast from the right bronchus. Due to concern for possible lymphatic abnormality, he underwent a second cardiac catheterization combined with lymphatic magnetic resonance imaging (MRI). 

Diagnostic Techniques and Their Most Important Findings:

The patient underwent a combined cardiac catheterization with lymphatic MRI imaging in a hybrid suite (Siemens 1.5T Sola MRI scanner and Artis Icono X-ray system) with a sliding door, allowing for seamless intermodality transfer. He was intubated, his inguinal lymph nodes were accessed bilaterally with 25G needles and his pacemaker was programmed to AAO 70. He was then transferred across the suite to the MRI scanner. Diluted Gadavist contrast was injected into the bilateral inguinal lymph nodes (diluted 1:10, total dose 0.2ml/kg). He then underwent T2 weighted 3D turbo spin echo sequence (T2 prep), dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) with TWIST sequence and conventional contrast enhanced MR angiogram (MRA). 

The T2prep sequence showed increased signal intensity in the supraclavicular region, mediastinum, and along the right lung hilum. On DCMRL, the thoracic duct course was clearly delineated and a prominent lymphatic collateral coursing to the right lung hilum was noted at the level of T6. In addition, a complex network of lymphatic channels was seen surrounding the right bronchus. On contrast enhanced MRA, the thoracic duct and right hilar collateral channel were delineated. The MR angiographic images were utilized as overlay on the fluoroscopic image guidance during lymphatic intervention. 

Learning Points from this Case:

The abnormal lymphatic collateral branch was occluded with liquid embolic material (Onyx, Micro Therapeutics, Inc., Irvine, CA). The patient tolerated the procedure well without adverse events. No further bronchial casts were expelled, and the patient was discharged home.

This case illustrates the utility of MRI for evaluation of lymphatic abnormalities in a patient with complex anatomy, pacemaker dependence, chronic pleural effusions, and plastic bronchitis in the setting of failing Fontan physiology. Specifically, MRI in this case helped delineate lymphatic anatomy and was used for image mapping for cardiac catheterization and intervention. Significant planning and inter-disciplinary collaboration were necessary to ensure patient safety and a successful procedure.