Utility of planning MRI in percutaneous thoracic duct embolization for chylothorax.

Purpose: Percutaneous thoracic duct embolization (TDE) is an accepted treatment for leaks of the central lymphatic ducts. In this study, we correlate the imaging findings on pre-procedural MRI lymphangiography with findings on conventional lymphangiography, and with operator ability to perform a technically successful TDE. The aim was to examine whether MRI is a good screening mechanism to support an invasive procedure in strong candidates, and avert one in poor candidates.

Materials And Methods: MRI and conventional lymphangiograms of 96 patients (62 male and 34 female; mean age 63 ± 11 years, range 29-92 years) were retrospectively reviewed. The diameter and level of the best target for access were assessed for each study. Technical success rates were evaluated with respect to presence of a cisterna chyli, target duct size, and target level concordance.

Results: Presence of a cisterna chyli on MRI significantly increased the likelihood of a successful TDE (68% vs. 42%, p = 0.03). Presence of a duct 4 mm or larger, by either modality, significantly improved the chance of successful TDE (for MRI, 65% vs. 41%, p = 0.04; for lymphangiography, 70% vs. 44%, p = 0.03). MRI was not helpful for localizing a lymphatic target, as less than half were seen within one and one-half vertebrae of the predicted level. There was a weak correlation (Pearson coefficient = +0.30) between duct size as measured on the two modalities. 95% of those without an identifiable target on MRI had a viable target on lymphangiography, and successful TDE was performed in 47% of those patients.

Conclusions: Identification of a cisterna chyli and/or 4 mm or greater target on pre-procedural MRI indicated higher likelihood of technically successful TDE. MRI did not help predict unsuccessful TDE procedures. Better target level concordance was not associated with improved technical outcomes.