Evaluation of lymphatic function by means of dynamic Gd-BOPTA-enhanced MRL in experimental rabbit limb lymphedema.

Background: The aim of this study was to investigate the value and technical methods of 3D dynamic contrast-enhanced magnetic resonance lymphangiography (MRL) in the assessment of lymphatic anatomy and function in the presence of extremity lymphedema.

Material/methods: An improved experimental model of obstructive lymphedema was established in 1 hind limb of 6 New Zealand White rabbits. 3D contrast-enhanced MRL was performed with a 3.0-T MR unit after the intracutaneous injection of Gd-BOPTA into the interdigital webs of the dorsal paws. Maximum-intensity projection (MIP) was used to reconstruct the images of the lymphatic system. The dynamic nodal enhancement in the popliteal fossa and time-signal intensity curves between lymphedematous and contralateral limbs were compared. Morphologic abnormalities of the lymphatic system were also evaluated and compared with lymphoscintigraphy (LSG).

Results: 3D dynamic contrast-enhanced MRL images were obtained after the administration of Gd-BOPTA. In the normal limb, the popliteal fossa lymph nodes and their afferent and efferent lymph-collecting vessels were clearly visualized as the Gd tracer was rapidly cleared from the interstitial compartment. In contrast, the Gd tracer accumulated slowly at the prior surgical site in the lymphedematous limb. The nodal enhancement of lymphedematous limbs was significantly less than that of the contralateral limbs (P<0.01). Types of time-signal intensity curves were also significantly different between the 2 groups (P<0.001).

Conclusions: 3D dynamic contrast-enhanced MRL can visualize the precise anatomy of lymphatic vessels and lymph nodes in extremity lymphedema, as well as objectively evaluate the functional status of lymph flow transport.