IMPROVED RESOLUTION OF MAGNETIC-RESONANCE MICROSCOPY IN EXAMINATION OF SKIN TUMORS

Magnetic resonance imaging has become increasingly important for visua lization and tissue differentiation of internal organs, Because of lim ited resolution, investigation of skin has been of little diagnostic v alue so far. We combined a homogeneous magnetic held of 9.4 T, as used in magnetic resonance spectroscopy, with gradient fields of 11.7 G/cm and an imaging unit to obtain a voxel resolution of 40 x 40 x 300 mu m(3). With this magnetic resonance microscopy unit, we studied normal skin, 12 nevocellular nevi, 20 basal cell carcinomas, 8 melanomas, and 8 seborrheic keratoses after excision in vitro, The specimens were vi sualized in spin-echo images. The proton relaxation times T1 and T2 we re determined for the different skin layers and tumor tissues, interpr etation of the spin-echo images was based on comparison with the corre lating histology, Epidermis, dermis, subcutaneous tissue, and hair fol licle complexes could be distinguished, Stratum corneum and hairs emit ted no signal, All tumors presented as distinct, signal-rich, homogene ous structures within the dark, signal-poor dermis, Their shape corres ponded to their outline in the histologic sections, Buds of superficia l basal cell carcinomas could be resolved, The proton relaxation times T1 and T2 were significantly different among all skin layers and tumo rs, Our results demonstrate that with sufficient resolution, different iation of skin tumors is possible using magnetic resonance imaging.