Der Radiologe
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Magnetencephalography (MEG) is a new diagnostic tool for the exact localization of the biomagnetic sources of the electrical activity of the brain. The extremely weak magnetic fields are generated by the postsynaptic activity of the neurons, acting like current dipoles. They are measured with a SQUID (superconducting quantum interference device). ⋯ The effect of background activity can be eliminated by alpha wave filtering and the dipole-density plot (DDP), which also increases the signal/noise ratio. MEG seems to be useful in purely functional lesions of the brain. A final decision on the value of MEG for routine diagnosis is not yet possible, however.
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The magnetic resonance imaging findings recorded in patients after surgery for degenerative disc disease in the lumbar and cervical spine are discussed in comparison with conventional radiographs and computed tomography findings. In the lumbar spine normal postoperative findings in the immediate postoperative period can be demonstrated by MR imaging. ⋯ In the cervical spine types of operative approaches, the appearance of bony stenosis and disc herniations by MR imaging are discussed. Computed tomography still has a role in the assessment of osseous complications such as central or foraminal stenosis.
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Preoperative chest X-rays were taken in both postanterior and partially lateral views of 94 children with foreign-body aspiration. Additional fluoroscopy was employed in 70 patients. In 7% of the cases, the foreign body was radiopaque; in an equal amount of cases, there were no radiological findings. In the remaining results we observed: emphysema as an indirect radiological sign in two-thirds of the cases; in less than one-third, poststenotic atelectasis; pneumonia in 10%; bronchitis in 9%; pneumothorax in 2%.
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If properly performed, modern high-resolution real-time ultrasonography will disclose subtle differences in the texture of thyroid tissue and thereby enable the examiner to suggest a diagnosis. Nevertheless, there is often a need for a more specific diagnosis of solid or semisolid thyroid lesions - especially when the lesion might be malignant. Ultrasonically guided fine-needle aspiration biopsy (UG-FNB) allows a final cytological and/or histological diagnosis to be made in patients with benign or malignant space-occupying growths even if they are small. ⋯ Since the tip of the needle can be visualized on the scan, the needle may be advanced or withdrawn during aspiration so it is possible to empty the cyst completely. The use of ultrasound in the follow-up of patients with thyroid cyst puncture is mandatory to evaluate the results. Surgical therapy should be reserved for large cysts causing space-occupying complications.