Correlation of MRI and histopathology findings in inflammatory skin diseases

Can spatial and contrast resolution be achieved with currently available MR devices for the successful assessment of inflammatory diseases of the skin? Method: High resolution MRI was performed in 20 patients with non-malignant diseases of the dermis and subcutis. The skin biopsies subsequent to the MR examinations were indicated for clinical reasons. The MR examinations were done in the location of later performed skin biopsies using a 1.0 Tesla system (Gyroscan T10 NT, Philips, Best, the Netherlands) and a surface coil of 7.5 cm inner diameter. Conventional spin-echo (SE-Sequenz)- and gradient-echo (GRE)-sequences were optimised to obtain maximum spatial resolution with a sufficient signal-to-noise ratio within a tolerable examination time. MR visualisation of histopathology was assessed by four readers using a questionnaire. Results: In 15 of 20 cases, high resolution MRI allowed a correct classification of the visualised dermal and subcutaneous patterns, in accordance with the histological work-up of the corresponding specimen. Due to the still only suboptimal spatial and contrast resolution the structure of the epidermis could not be assessed adequately. Determination of contrast enhancement or non-enhancement after administration of intravenous contrast agent provided information on the degree of tissue perfusion in 19 patients, which complemented the morphological assessment. Conclusion: High resolution MRI allows to identify non-invasively histological main patterns of inflammatory skin diseases. However, final diagnosis often depends on higher microscopic resolution and special staining.