| 1. |
- Brockstedt, Sara, et al.
(författare)
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Vertical field MR imaging of upper thorax and spine in small children. Evaluation of a new surface coil
- 1993
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Ingår i: Acta Radiologica. - 1600-0455. ; 34:6, s. 549-553
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Tidskriftsartikel (refereegranskat)abstract
- To improve image quality in a vertical field MR imaging unit, operating at low field strength (0.3 T), we have designed a half-elliptical coil for use in the upper thoracic region of small children. Our intention was also to shorten the examination time, which until now has been long, because several scans with different coils have been necessary to cover the thoracic region. The experimental coil is designed so that a child's shoulders fit into the central region. The coil consists of 2 serially connected cable-loops, mounted on a foam rubber vest. The coil performance was tested in a phantom and improvements relative to standard coils were demonstrated in in vivo studies. The results indicate that by using the half-elliptical coil, the signal-to-noise (S/N) ratio can be improved by a factor of 2 to 3 in the thoracic region of a child.
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| 2. |
- Larsson, Elna-Marie, et al.
(författare)
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Aortic pathology revealed by MRI in patients with clinical suspicion of spinal disease
- 1993
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Ingår i: Neuroradiology. - 1432-1920. ; 35:7, s. 499-502
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Tidskriftsartikel (refereegranskat)abstract
- In five patients with clinical suspicion of spinal disease, MRI of the spine revealed unexpected aortic pathology explaining the symptoms. No significant intraspinal pathology was found on MRI. However, in one patient with clinical suspicion of spinal stenosis, an aortic occlusion was detected on MR images of the spine. The lower extremity ischaemia, caused by the occlusion, was responsible for the symptoms. In another patient a paravertebral haematoma from a ruptured aortic aneurysm resulted in spinal nerve compression, thought before MRI to be caused by a spinal tumour. In three patients aortic aneurysm or dissection resulted in spinal cord ischaemia with symptoms mimicking those of compressive spinal disease. Thus, if MRI of the spine does not provide an explanation for the patient's symptoms, examination of the aorta is recommended.
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| 3. |
- Li, M H, et al.
(författare)
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MRI of extradural spinal tumours at 0.3 T
- 1993
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Ingår i: Neuroradiology. - 1432-1920. ; 35:5, s. 370-374
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Tidskriftsartikel (refereegranskat)abstract
- Ninety-one patients with extradural spinal tumours were examined by magnetic resonance imaging. There were 76 metastases (6 from unknown primary tumours). Seven patients had primary spinal tumours and 8 had multiple myeloma. Sixteen had bulging, diseased vertebral bodies compressing the subarachnoid space and 67 had extradural tumour compressing the spinal cord. Sixty patients had paravertebral involvement. Intraspinal involvement did not correlate with the extent of spinal lesions. All patients had vertebral destruction, with hypointense or combined hypo- and isointense signal relative to bone marrow on T1-weighted images. In most of the 22 patients with T2-weighted images the tumours were isointense or slightly hyperintense. It was usually impossible to differentiate the various tumours on the basis of signal intensity and morphology. However, metastases from carcinoma of the prostate were often more hypointense than other tumours on T1- and T2-weighted images. An inhomogeneous pattern in which diffusely low signal is combined with focal lower signal on T1-weighted images may suggest myeloma. In the 22 patients examined with both T1- and T2-weighted images, T1-weighted images gave the best information in 18; in 3 they were equivalent and in 1 inferior to T2-weighted images; they are therefore recommended for routine imaging of epidural spinal tumours.
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| 4. |
- Lindgren, Arne, et al.
(författare)
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Cerebral lesions on magnetic resonance imaging, heart disease, and vascular risk factors in subjects without stroke. A population-based study
- 1994
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Ingår i: Stroke: a journal of cerebral circulation. - 1524-4628. ; 25:5, s. 929-934
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: To assess the prevalence of asymptomatic abnormalities on magnetic resonance imaging of the brain and their possible relation to hypertension, heart disease, and carotid artery disease, we studied 77 randomly selected subjects (mean age, 65.1 years; range, 36 to 95 years) with no history of focal brain lesions. METHODS: The study protocol included magnetic resonance imaging of the brain, transthoracic and transesophageal echocardiography, ultrasonography of the carotid arteries, and electrocardiographic recording. Deep and periventricular white matter hyperintensities on magnetic resonance imaging were assessed both separately and together. RESULTS: On magnetic resonance imaging of the brain 62.3% (95% confidence interval [CI], 51.5% to 73.2%) of the subjects had white matter hyperintensities. These abnormalities increased significantly with age (chi 2 test; P = .0001), from 13.6% (95% CI, 0% to 28.0%) of subjects aged younger than 55 years to 85.2% (95% CI, 71.8% to 98.6%) of subjects aged 75 years or older. Six subjects had deep gray matter hyperintensities localized in the basal ganglia, and one had a cerebellar infarction. Stepwise logistic regression analysis identified age and a history of heart disease (but not echocardiographic findings) to be independently associated with deep and periventricular white matter hyperintensities. Hypertension was only independently associated with periventricular white matter hyperintensities. Of the 68 subjects examined with both transthoracic and transesophageal echocardiography, potential cardioembolic sources were detected in 38.2% (95% CI, 26.7% to 49.8%) of the subjects with transthoracic echocardiography and in 47.1% (95% CI, 35.2% to 58.9%) of those with transthoracic and transesophageal echocardiography combined. In subjects aged 75 years or older, a possible cardiac embolic source was detected in 64.0% on transthoracic echocardiography and in 72.0% on transthoracic and transesophageal echocardiography combined, compared with 5.3% and 15.8%, respectively, in subjects aged younger than 55 years. CONCLUSIONS: White matter hyperintensities and potential cardioembolic sources are frequently present in asymptomatic individuals, stressing the need for age-matched control subjects in studies of patients with stroke or dementia.
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| 5. |
- Malmgren, Lars, et al.
(författare)
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Improved receiver coil for upper thoracic spine imaging in a vertical magnetic field
- 1992
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 2:2, s. 191-195
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Tidskriftsartikel (refereegranskat)abstract
- To improve image quality in the upper thoracic spine, an anatomically shaped copper wire loop coil, made to fit over the patient's shoulders, was constructed. The coil was permanently mounted on a foam-rubber vest to facilitate attachment to the patient. Phantom and in vivo studies of the performance of the coil in healthy volunteers showed as much as a two times greater signal-to-noise ratio relative to that of standard coils for the upper thoracic spine. In a patient with lesions in the upper thoracic cord, the coil gave better image quality in the region of interest than did the standard coils. The coil has been integrated into the authors' routine imaging equipment and has been the coil of choice for imaging of the upper thoracic spine on their 0.3-T vertical field system.
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| 6. |
- Redlund-Johnell, Inga, et al.
(författare)
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Subluxation of the upper thoracic spine in rheumatoid arthritis
- 1993
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Ingår i: Skeletal Radiology. - 1432-2161. ; 22:2, s. 105-108
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Tidskriftsartikel (refereegranskat)abstract
- Only single cases with rheumatoid arthritis of the thoracic spine with vertebral subluxation have been reported to date. In a review of 100 patients with severe rheumatoid arthritis who had undergone occipitocervical fusion, arthritis of the upper thoracic spine with subluxation was discovered on conventional radiographs in four patients. Two additional patients were found elsewhere. Magnetic resonance imaging (MRI) was performed in three of the patients, confirming the diagnosis of subluxation of the upper thoracic vertebrae. In addition, MRI revealed encroachment on the anterior subarachnoid space and compression of the spinal cord.
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| 7. |
- Svahn, Gudmund, et al.
(författare)
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PACS for radiology conferences--improvement of application software
- 1994
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Ingår i: Computer Methods and Programs in Biomedicine. - 0169-2607. ; 43:1-2, s. 81-84
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Tidskriftsartikel (refereegranskat)abstract
- The introduction of PACS in a radiology department means that most functions that are available in the film-based system must be included. One important function is the radiology conference. The handling and application programs of digital workstations are normally not developed for demonstrations of many images in a limited time. This paper describes a workstation with specially designed software for radiology conferences. The application is separated in preparation and presentation of the cases to be demonstrated. Very fast image handling is achieved during the conference because the function is based on the principle of prefetching of the selected images. The images are presented on a large screen with high resolution. The experiences of digital radiology conferences are good. However, reference films from previous examinations create extra work because they have to be shown on the conventional lightbox.
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| 8. |
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