Neuroimaging clinics of North America
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Neuroimaging Clin. N. Am. · Aug 2003
ReviewHodgkin and non-Hodgkin lymphoma of the head and neck: clinical, pathologic, and imaging evaluation.
Lymphomas are subdivided into HL and NHL and are more specifically classified into subtypes of HL or NHL according to the WHO classification. HLs involve the lymph nodes predominantly and only approximately 5% arise in extranodal sites, whereas 30% of NHLs present in extranodal sites. Imaging studies, including CT and MR imaging, cannot distinguish [figure: see text] HL from NHL, and cannot differentiate their various subtypes, necessitating a pathologic diagnosis. ⋯ MR imaging is preferred for the assessment of extension of lymphomas to different fascial spaces (parapharyngeal, masticator, infratemporal fossa, tongue, and nasopharynx) and for intracranial extension. Lymphomas are isodense to muscle on CT and circumscribed with distinct margins that occasionally display extranodal extension with less-well-defined margins and areas of necrosis within the tumor matrix. Lymphomas appear low in signal intensity on T1-weighted images and low to high in signal intensity on T2-weighted images, with variable, but usually low, enhancement following introduction of Gadolinium-DTPA (Gd-DTPA) contrast material.
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Cystic lesions appearing in the maxilla and mandible have been shown with their typical radiographic features. In addition, this article has presented radiographic techniques used to diagnose these lesions. ⋯ Key features to differentiate among these cysts have been discussed. Finally, the article discussed the differentiation of jaw cysts from benign tumors that appear in the jaws.
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Neuroimaging Clin. N. Am. · Aug 2003
ReviewNasopharynx: clinical, pathologic, and radiologic assessment.
NPC represents 0.2% of malignant disease in the white population but is more common in southern China, among Chinese in East Asia and the United [figure: see text] States, and in North Africa, including Saudi Arabia. NPC in these ethnic groups tends to manifest at a younger age. Undifferentiated carcinoma is the most common histopathologic type and is associated with EBV. ⋯ In addition, the metastatic lymph nodes in the neck reveal no specific imaging features that would allow differentiation from other lymph node metastases. They may be discrete, often multiple, and large and bulky displaying a variable degree of necrosis and enhancement following introduction of contrast material. Local recurrence manifests commonly within the first 2 to 3 years posttherapy and is optimally evaluated by MR imaging and PET scanning.
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Benign odontogenic tumors are characterized by imaging findings of expansile growth and well-defined margins with smooth borders, and their appearance is very similar to that of odontogenic and nonodontogenic cysts. From the viewpoint of diagnostic imaging of odontogenic tumors, teeth are designed differently according to their origin from the apex or crown. Therefore, for differential diagnosis, it is necessary to select diagnostic methods that make it possible to evaluate these findings in detail. ⋯ MR imaging is effective in differentiating between tumors and cysts, evaluating the infiltration of malignant tumors in the jawbone and surrounding soft tissue, and detecting bone marrow changes of the jaw. Differentiation between tumors and cysts must be achieved by contrast-enhanced studies. Combining plain radiography with advanced imaging techniques, including CT and MR imaging, can improve the accuracy of diagnosing odontogenic tumors.
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Neuroimaging Clin. N. Am. · Aug 2003
ReviewFibro-osseous and giant cell lesions, including brown tumor of the mandible, maxilla, and other craniofacial bones.
Fibro-osseous, osseous, cartilaginous, and giant cell lesions of the mandible, maxilla, and other craniofacial bones share overlapping clinical, radiologic, and pathologic features that may lead to diagnostic confusion and possible misdiagnosis. The value of combined clinical-radiologic-pathologic correlation in the diagnosis of these lesions is paramount to achieving the correct diagnosis with subsequent implementation of appropriate therapeutic intervention.