Neuroimaging clinics of North America
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Infections of the head and neck vary in their clinical course and outcome because of the diversity of organs and anatomic compartments involved. Imaging plays a central role in delineating the anatomic extent of the disease process, identifying the infection source, and detecting complications. The utility of imaging to differentiate between a solid phlegmonous mass and an abscess cannot be overemphasized. This review briefly describes and pictorially illustrates the typical imaging findings of some important head and neck infections, such as malignant otitis externa, otomastoiditis bacterial and fungal sinusitis, orbital cellulitis, sialadenitis, cervical lymphadenitis, and deep neck space infections.
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Fungal infections of the central nervous system (CNS) frequently occur in the immunocompromised or debilitated host. Imaging findings are non-specific but may be organized into extra-axial, parenchymal, and vascular categories. Furthermore, knowledge of fungal morphology may predict the imaging manifestations with large, hyphal species having a predilection for brain parenchymal involvement, while small, unicellular organisms typically result in meningitis. Advanced imaging techniques such as diffusion-weighted imaging, MR perfusion and MR spectroscopy, when combined with clinical findings, may help in differentiating fungal disease from other mimckers such as pyogenic infection or cystic metastases.