MRI evaluation of soft tissue hydatid disease

infestation in soft tissue by Echinococcus granulosus is not a common disea se, and its diagnosis,is based on clinical, laboratory data and radiologica l findings. The aim of our retrospective study is to give an overview of th e different signs and patterns shown by MRI that can be useful in character izing soft tissue hydatid disease. The MRI images obtained in. seven patien ts with soft tissue and subcutaneous hydatidosis were reviewed. Typical sig ns of hydatidosis were multivesicular lesions with or without hypointense p eripheral ring ("rim sign"). Related to the presence and absence, respectiv ely, of viable scolices in the microscopic exam, daughter cysts were presen ted either as high signal intensity or low signal intensity on T2-weighted images. Low-intensity detached layers within the cyst and peripheral enhanc ement with gadolinium-DTPA were also presented. Atypical signs were present ed in an infected muscular cyst, a subcutaneous unilocular cyst and several unilocular cysts. Knowledge of the different patterns in MRI of soft tissu e hydatid disease can be useful in ? diagnosing this entity. We observed th at the "rim sign" is not as common as in other locations, and in addition, MRI seems to be of assistance when evaluating the vitality of the cysts.