Intranodal CT lymphangiography (ICTL): Diagnostic and therapeutic role in post-operative chylothorax

A 39-year-old male patient without known comorbidities presented with a 3-month history of gradually progressive dysphagia (preferential to solids) with diminished appetite and unquantifiable weight loss.

CT

CECT demonstrated enhancing circumferential mural thickening involving the lower third oesophagus with regional lymphadenopathy (Figures 1a and 1b). Upper GI endoscopic biopsy confirmed a well-differentiated squamous cell carcinoma.

The patient underwent surgical resection and developed high output chylous discharge from the right intercostal drainage tube on post-op day 4 onwards. Lab examination confirmed the chylous leak.

Intranodal CT lymphangiography (ICTL)

Under sonographic guidance, the right inguinal lymph node was accessed using a 21G needle, and 15 ml Lipiodol was injected slowly. The ascent of Lipiodol through inguinal and retroperitoneal lymphatic channels was evaluated on serial limited field of view cranial CT runs, performed every 15 minutes for a duration of one hour until contrast opacification of the thoracic duct was achieved (Figures 2a and 2b). However, no definitive contrast leak was demonstrated even on 4-hour delayed imaging.

CT-guided lymphatic intervention

The cisterna chyli was identified in the left para-aortic region at L1–L2 disc level and accessed under CT guidance with an 18G Chiba needle (Figures 3a and 3b). After confirming the needle tip location, it was flushed with 5% dextrose solution. Subsequently, 1.0 ml of 50% diluted nBCA glue was administered into the cisterna chyli (Figure 3c). Post-procedure, there was a complete cessation of chylous discharge from day 2 onwards.

Background

Chylothorax is defined as chylous extravasation into the pleural cavity. Esophagectomy and cardiothoracic vascular procedures for congenital heart disease are the two most common causes of post-surgical chylothorax [1]. Biochemical analysis confirms chylothorax by triglyceride content > 110 mg/dL and/or the presence of chylomicrons in the pleural fluid [2].

Clinical Perspective

High output chylous discharge (> 10 ml/kg/day) has high morbidity and mortality due to elevated risk of sepsis [3] and warrants prompt treatment. Surgical management with thoracic duct ligation (TDL) via thoracic or abdominal approach is the procedure of choice at most institutions [4].

Imaging/Intervention Perspective

Although conventional lymphangiography using fluoroscopy is the standard investigation modality in many institutions, intranodal CT lymphangiography (ICTL) is a worthy alternative since CT is a more widely available modality. This procedure is technically less challenging and less time-consuming, and it also excels in depicting the 3-dimensional anatomic correlation with vital regional structures for guiding interventional management. Therefore, ICTL and imaging-guided lymphatic embolisation should be considered before opting for re-exploratory TDL surgery in all such cases that carry much higher morbidity and mortality.

Although radiation dose from serial CT abdomen scans is a concern vis-à-vis conventional fluoroscopy, it can be offset to some extent by restricting the field of view (FoV) and leapfrogging across the area of interest (abdomen and chest) based on rate of contrast ascent, usually enabling complete coverage over 4–6 limited FoV CT runs.

Teaching Points

Intranodal CT lymphangiography (ICTL) is a technically feasible, cost-effective modality to study lymphatic anatomy, especially in post-operative chylothorax patients. It not only enables precise localisation of chylous leaks but also guides the interventional radiologist in planning minimally invasive, image-guided lymphatic embolisation procedures as a definitive management strategy in high-output iatrogenic chylothorax patients.

Written informed patient consent for publication has been obtained.