In children, hematogenous osteomyelitis is an infection that primarily affects the most vascularized regions of the growing skeleton. The disease has increased in frequency, virulence, and degree of soft-tissue involvement. The change in clinical manifestations and management over the past 2 decades should be reflected in the current imaging approach to the disease. Imaging of infection must depict the location of a single focus or of multiple foci of involvement and the presence of drainable collections. This review provides an overview of the imaging implications directed by the changing epidemiology, the newer insights of anatomy and pathophysiology, the imaging characteristics with emphasis on specific locations and disease complications, and the differential diagnosis considerations. In addition, basic imaging guidelines for appropriate extent of area to image based on patient age are provided.

Multiparametric magnetic resonance imaging (MRI) is essential in the evaluation of sonographically indeterminate adnexal lesions, because it enables an adequate characterization of these lesions and their classification based on the degree of suspicion for malignancy. It also allows the most accurate therapy and/or follow-up approach, limiting the associated costs. The majority of indeterminate adnexal lesions at ultrasound are benign and its characterization with MRI avoids unnecessary and inappropriate surgery. Only a minority of these lesions corresponds to malignant adnexal disease, and their proper evaluation by MRI allows timely implementation of the correct therapeutic approach, which is the key aspect in the management of these tumors. In this article the authors review and illustrate the MRI characteristics of the sonographically indeterminate adnexal lesions, which classifies them attending to their degree of suspicion. The multiparametric MRI protocol that should be applied in the study of these tumors is also highlighted.

Key-words: Adnexal Diseases; Ultrasound; Magnetic Resonance; Classification.