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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Case Reports
[Venous anomalies of the brain. The clinical significance of the so-called venous angioma].
In contrast to angiography, MRI not only allows the diagnosis of DVA (developmental venous anomaly, so-called venous angioma), but also shows up cavernomas and other angiographically occult vascular malformations. It also differentiates between DVAs and occult true malformations. This has completely changed the pathological assessment of DVAs. ⋯ In rare cases this can result in haemodynamic disturbances, thrombosis and ischaemia. Wall rupture with bleeding does not occur in DVA. It must be assumed that bleeding reported in patients with DVAs before the availability of MRI resulted from an associated true vascular malformation in most cases.
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A CT study was carried out on 43 patients with low back pain and sciatica who were treated conservatively. They were followed up for over 20 months (mean) clinically and monitored by CT before and after treatment. Initially, 38 of them had herniation and 5 had protrusion of the disc. ⋯ In 76.7% of the patients CT showed an improvement (clear regression in 15 patients, moderate decrease in 18 patients). A favourable tendency towards regression was observed in disc herniation at the L5-S1 level and in cases showing sequestration. The prognosis was unfavourable in herniations at higher levels than L5-S1 and in lateral herniation reaching the intervertebral foramen.
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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%.