LYMPHEDEMATOUS SKIN AND SUBCUTIS - IN-VIVO HIGH-RESOLUTION MAGNETIC-RESONANCE-IMAGING EVALUATION

Physico-chemical and morphologic parameters of skin layers and subcuta neous tissue in lymphedematous limb were studied in vivo using magneti c resonance imaging. High resolution images were obtained with a depth resolution of about 70 mu m, using a specific surface gradient coil s pecially designed for skin imaging and connected to a standard whole-b ody imager at 1.5 T., Twenty-one patients with unilateral lower extrem ity lymphedema (11 primary and 10 secondary) were examined, Skin thick ness, relaxation times, and relative proton density were calculated in lymphedematous limbs and in contralateral extremities. In diseased li mbs, the average skin thickness (2.17 mm) was significantly larger (p = 1.5 x 10(-4)) than that of contralateral limb (1.14 mm). Major cutan eous alterations due to lymphedema took place in dermis. In lymphedema tous dermis, the significant increase of relaxation time values could be due to a shift in the equilibrium of water inside this tissue in re lation to the interactions between macromolecules and water molecules. In lymphedematous epidermis our results showed an increase in the num ber of free water protons. Information about water and fat distributio n in lymphedema was also obtained using chemical shift weighted images . Our results demonstrated a water retention diffusely spread over the entire dermis, and an important fluid retention located in the interl obular spacing and beside the superficial fascia, Inside the subcutis, the mean thickness of the superficial fat lobules was increased more than that of the deep fat lobules, From all the various measurements w e could not distinguish primary from secondary lymphedema.