OBJECTIVETo evaluate anatomical and functional images of contrast MR lymphangiography in the diagnosis of limb lymphatic circulation disorders.

METHODS30 patients with limb lymphedema were enrolled in the study. There were 27 patients of primary lymphedema and 3 of secondary lymphedema. Contrast enhanced lymphangiography was performed with 3.0 T MR Unit after intracutaneous injection of gadobenate dimeglumine into the interdigital webs of the dorsal foot and hand. The kinetics of enhanced lymph flow within the lymphatics were calculated using the formula: Speed (cm) = total length of visualized lymph vessel (cm)/ inspection time (minutes) and by comparing dynamic nodal enhancement and time-signal intensity curves between edematous and contralateral limbs. Morphological abnormalities of the lymphatic system were also evaluated.

RESULTSFollowing injection of the contrast agent enhanced lymphatic channels were consistently visualized in all clinical lymphedematous limbs and five contralateral limbs of unilateral lymphedema cases. The speed of enhanced flow within the lymphatics of lymphedematous limbs ranged from 0.30 to 1.48 cm/min. The contrast enhancement in inguinal nodes of edematous limbs was significantly lower than that of contralateral limbs (P < 0.01). Dynamic measurement of contrast enhancement showed a remarkable lowering of peak time (P < 0.01) and peak enhancement (P < 0.01) and a delay in outflow in inguinal nodes of affected limbs compared with that of control limbs. Post-contrast MR imaging also depicted varied distribution patterns of lymphatics and abnormal lymph flow pathways within lymph nodes in the limbs with lymphatic circulation disorders.

CONCLUSIONSContrast MR lymphangiography with gadobenate dimeglumine was able to visualize the precise anatomy of lymphatic vessels and lymph nodes in lymphedematous limbs. It also provided comprehensive information about the functional status of lymph flow transportation in lymphatics and lymph nodes.