Der Radiologe
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Review Comparative Study
[Isolated vasculitis of the central nervous system].
Vasculitis is a rare cause for disease of the CNS. The isolated vasculitis of the CNS is restricted to the CNS whereas other forms of vasculitis affect various organs including the CNS. Headache, encephalopathy, focal deficits and epileptic seizures are the major symptoms suggestive for vasculitis. ⋯ MRI demonstrates multiple lesions which in part show enhancement after gadolinium. A definite diagnosis can only be made on the grounds of biopsy from leptomeninges and parenchyma. Therapy consists of corticosteroids and cyclophosphamid.
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The hematogenous spread of bacteria, fungi and protozoa may also reach the brain vessels, which happens mostly through septic emboli. From such an embolus a metastatic focal encephalitis and later a septic-embolic brain abscess may arise. The most frequently underlying infections that may cause septic emboli are bacterial endocarditis as well as bacterial infections of artificial heart valve prostheses. ⋯ They occur frequently as multiple lesions. MRI is superior to CT in depicting the different stages of evolution from focal encephalitis, through the hardly encapsulated early abscess, to the formation of a membrane and later a dense fibrous capsule. The medical treatment of a brain abscess requires properly performed CT or MRI follow-up examinations in order to realize early enough a possible growing of such a lesion.
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The diagnosis of chronic osteomyelitis is made on the basis of clinical, radiologic and histologic findings. The role of imaging in patients with known chronic osteomyelitis is to detect and to delineate areas of active infection. To correctly interpret the imaging findings, it is essential to take both the individual clinical findings and previous imaging studies into account. ⋯ Computed tomography can be used to evaluate even discrete or complex bony alterations and to guide percutaneous biopsy or drainage. Magnetic resonance imaging achieves the best diagnostic sensitivity and specificity and provides superior contrast as well as anatomical resolution in both bone marrow and soft tissues. In this paper the features and clinical relevance of imaging in primary chronic osteomyelitis, posttraumatic osteomyelitis, tuberculous spondylitis and osteomyelitis of the diabetic foot are reviewed, with particular respect to MRI.
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Ewing's sarcoma is a highly malignant neoplasm of the bone whose origin is still uncertain. A strong relationship exists between Ewing's sarcoma and tumors of neural origin (Ewing family of tumors). Ewing's sarcoma must be distinguished from other round-cell tumors like lymphoma and neuroblastoma and also must be differentiated from osteogenic sarcomas. ⋯ Magnetic resonance imaging is the imaging modality of choice to evaluate the extent of the primary lesion, to monitor the response to neoadjuvant chemotherapy and to follow up non-resected Ewing's sarcomas. Bone scintigraphy is necessary to detect skeletal metastasis, and 201thallium scanning has been shown to be sensitive in the monitoring of treatment response. Today, computed tomography is not longer used to image the tumor site; however, spiral CT of the lungs plays a central role as a staging and follow-up tool.