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Biomedical subjects

L Ketonen

Publications and source records attributed to L Ketonen.

80 records · Page 5Linked to original sources
PubMedDate not supplied

Cerebral MR and CT imaging in Creutzfeldt-Jakob disease.

Magnetic resonance (MR) imaging and CT of three patients with Creutzfeldt-Jakob disease (CJD) showed bilateral cortical atrophy and no apparent white matter changes. Serial examinations revealed the progressive nature of the atrophy, findings compatible with the patients' clinical deterioration. At autopsy some white matter abnormalities were detected in one patient 6 months after MR imaging. The available data suggest that the white matter abnormalities, if present, develop during the final stage of CJD.

Aged↗
PubMedDate not supplied

Hypodense white matter lesions in computed tomography of neurosarcoidosis.

Cerebral CT was performed on 32 patients with neurosarcoidosis and found to be abnormal in 13 (41%). One of the most common abnormalities (five patients) was represented by low density white matter lesions, which have not, to the best of our knowledge, been previously reported in association with neurosarcoidosis. Other types of abnormalities were ventricular enlargement (five patients) and mass lesions (four patients). Nineteen of the 32 patients had normal CT findings; thus normal CT does not exclude neurosarcoidosis. Nine magnetic resonance examinations carried out in seven patients failed to reveal more lesions than CT.

Adult↗
PubMedDate not supplied

A comparison of default and reduced bandwidth MR imaging of the spine at 1.5 T.

The value of a reduced bandwidth MR imaging technique was tested prospectively in 51 spinal MR examinations by using default (16 kHz) bandwidth, 2000/30, 90 (TR/TEs) and 600/30, and reduced (8 kHz) bandwidth, 2000/48, 92 and 600/30, techniques at 1.5 T. Bandwidth reduction was used to maintain the signal-to-noise ratio for a reduced scan time. Concerns have been raised as to the effect of bandwidth reduction at high field, since a savings in time or an increased signal-to-noise ratio occur at the expense of increased chemical shift misregistration artifact. However, when appreciable, the chemical shift-related artifact in the spine was typically located in the frequency-encoding direction at the vertebral body/disk space interface or the dural sac/epidural fat interface in the lower lumbosacral region and was easily distinguished from pathologic lesions. There were no missed diagnoses with the reduced bandwidth technique. This study suggests that chemical shift-related artifact will rarely be confused with pathology by an experienced reader and suggests a clinical role for the bandwidth technique to decrease scanning time in uncooperative patients or to allow acquisition of additional imaging planes in a reasonable time.

Adolescent↗
PubMedDate not supplied

Low-field MRI in the evaluation of rheumatoid cervical spine. Comparison with neurological findings and routine plain radiography.

The usefulness of a low-field magnetic resonance imaging (MRI) instrument in the evaluation of cervical spine abnormalities was studied in 20 patients with rheumatoid arthritis and known anterior atlantoaxial subluxation (AAS) (16 patients) or other cervical spine abnormalities (4 patients). The MRI results were compared with routine plain radiographs and with neurological findings. Three patients had a clinical suspicion of cervical spinal cord compression. This was confirmed by MRI, which additionally detected one more patient with compressive myelopathy. Anterior AAS in MR images was seen in 4 patients, but proper flexion images were not obtained. Atlantoaxial impaction was detected by a recent method of Sakaguchi-Kauppi in 16 patients as compared to 9 patients by the McGregor method and 4 patients by MRI. Most of the clinically important consequences of rheumatoid cervical spine are seen with a low-field MR imager, but detailed bony changes and precise measurements are better evaluated with plain X-rays.

Adult↗
PubMedDate not supplied

Efficacy of gadolinium in MR brain imaging of HIV-infected patients.

PURPOSE: To determine the value of gadolinium in routine head MR imaging of HIV-infected patients. METHODS: One hundred and three consecutive human immunodeficiency virus-infected patients referred for head MR imaging were scanned without and with intravenous gadopentetate dimeglumine (Gd-DTPA) contrast. RESULTS: The precontrast scans of 82 patients were either normal, or had atrophy or diffuse white matter changes only. Sixteen of these 82 demonstrated enhancing abnormalities: eight meningeal/ependymal enhancement and eight focal enhancing lesions. Twenty-one of the 103 scans had focal or mass lesions on the precontrast images; in eight of these scans, new information was obtained with Gd-DTPA. Of the 24 patients in both groups where new information was obtained with Gd-DTPA, the information contributed to a change in the clinical care of nine patients. CONCLUSION: Gadolinium-enhanced MR is useful in the management of selected patients with human immunodeficiency virus infection, for example those with symptoms suggesting meningeal involvement, focal brain lesions, or if the unenhanced MR does not explain all the patient's symptoms.

AIDS Dementia Complex↗