Acta radiologica
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The poor localization facility of interventional instruments in MR imaging has been one of the major obstacles to the popularization of interventional MR imaging. It has been suggested that the Overhauser enhancement be used to generate markers of small size and high visibility. This article studies the feasibility of a localization marker based on this method. ⋯ Its small size and high signal-to-noise ratio, together with immunity to most system nonlinearities and imaging errors, makes the Overhauser marker a promising localization method for the accurate positioning of interventional devices. The method may be applied at any field strength, and markers are visible in images obtained with any practical imaging sequence.
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Case Reports
Microcatheter embolization of arteriovenous fistulas in the subclavian region. Report on three cases.
The retrospective evaluation is presented of 3 patients treated with endovascular embolization of arteriovenous fistulas (AVFs) in the subclavian region. ⋯ AVFs in the subclavian region can be treated by using microcatheters and fibered platinum microcoils.
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To assess the value of imaging by 0.1 T MR and by 99mTc-HMPAO-labeled leukocytes in confirming skeletal infection in patients with soft-tissue infections and/or bone pathology. ⋯ Combined imaging with MR and 99mTc-labeled leukocytes is recommended in diagnostically complicated bone infections except for spondylitis where MR is the method of choice. Congruent positive findings are highly suggestive of infection, the extent of which can be determined. Congruent negative results exclude infection.
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Pericardial effusion in patients who have recently undergone cardiac surgery is often trapped in compartments. CT of the pericardium provides good information about the distribution of pericardial fluid in the postoperative period after cardiac surgery. Contrary to echocardiography, CT imaging is not affected by postoperative mediastinal emphysema and pain from the wound. A method for CT-guided pericardiocentesis was developed. ⋯ CT-guided pericardiocentesis offers a new possibility in patients where fluoroscopically or echocardiographically guided pericardiocentesis is difficult.
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Comparative Study
Postoperative lumbar MR imaging with contrast enhancement. Comparison between symptomatic and asymptomatic patients.
PURPOSE AND MATERIAL: Contrast-enhanced MR imaging of the spine after surgery for lumbar disk herniation almost always shows pathologic changes. To investigate to what extent these changes are correlated to patients' actual clinical symptoms, we compared the postoperative MR findings in 19 asymptomatic patients with 42 symptomatic patients (43 levels). ⋯ Sixteen percent of the asymptomatic and 42% of the symptomatic patients had disk herniation at the level of previous surgery. Most of the herniated disks were found in the symptomatic patients less than one year after surgery. The amount of epidural scar tissue, displacement and thickening of nerve roots, and compression of the dural sac were also studied. Disk herniation as a probable cause of recurrent sciatica was a common finding among symptomatic patients examined one year or less after surgery. In comparing asymptomatic patients and symptomatic patients with more than one year between surgery and MR examination, no significant radiologic differences, including disk herniation, were found.