Comparison of quantitative EEG parameters from four different analysis techniques in evaluation of relationships between EEG and CBF in brain infarction.
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Adult↗
Biomedical subjects
U Tolonen
Publications and source records attributed to U Tolonen.
Serial measurements of quantitative EEG and cerebral blood flow and circulation time after brain infarction.
The quantitative EEG (QEEG), regional cerebral blood flow (rCBF) and circulation time of 17 patients were examined semisimultaneously thrice during the first 3 months after a cerebral supratentorial infarction. The EEG was quantified according to normalized slope descriptor technique in nine patients and by means of a combined period and amplitude analysis in eight patients. Intravenously injected isotopes 133Xenon and 99TcmO4 were used for blood flow and circulation time measurements. The QEEG-values improved during the whole follow-up period. Cerebral blood flow stayed low for all 3 months and did not alter during this period, while initially prolonged circulation time to some extent improved within 2 weeks remaining, however, prolonged even thereafter. A tendency for a positive correlation between QEEG and rCBF values in the infarcted hemisphere could be seen.
Adult↗
Quantitative 99mTechnetium cerebral circulation time in brain infarction. Its relation to clinical findings, electroencephalograms and conventional radionuclide studies.
Four circulation time parameters were measured by intravenously injected 99mTechnetium and a gamma camera in 183 patients displaying a unilateral supratentorial brain infarction. The mean values of all the calculated circulation time parameters in the infarcted hemisphere were significantly slower than those of the contralateral hemispheres. The difference between the hemispheres proved a more sensitive parameter than absolute values. Both the quantitative circulation time differences between the hemispheres and the absolute circulation time values showed significant correlations with several clinical findings, e.g. severity of infarction, recovery from infarction, and patient's age. However, quantification gave only a minor addition to the number of the patients with abnormalities detected by routine static and dynamic brain scintigrams. Though the value of the quantitative intravenous 99mTechnetium method in routine clinical work is limited, it provides valuable information on the haemodynamics in brain infarction, e.g. the persistence of measurable asymmetry suggesting decreased function even of non-infarcted parts of the affected hemisphere ("deafferentiation").
Adult↗
Evaluation of cerebral infarctions of the carotid area by an intravenous 133Xenon and 99mTechnetium method.
Quantitative determinations of regional cerebral blood flow (rCBFf, rCBFm) and volume (rCBV), transfer time (rCTT) and fast compartmental weight (Wf) were performed in 34 patients with infarctions of the carotid area by a 133Xe and 99mTc intravenous injection method. The results were compared with clinical signs and electroencephalographic (EEG) findings. A significant difference was found between the lesion side and the control side in all the parameters except rCBV. This difference increased with the severity of the infarction and age of the patients. The difference between the two sides was especially great in the patients with totally occluded internal carotid artery. A slight diaschisis could be observed in the present infarction group. An almost significant reduction on the "normal side" was seen in Wf. In order to assess the reciprocal influence of all the different blood flow parameters, the difference index (DI): Formula: (see text) was calculated, where delta i = the difference between the two sides in one parameter expressed in percent. This proved to be abnormal in 80% of the patients. The atraumatic isotope technique employed offers a good opportunity for the quantitative evaluation of hemodynamics in cerebral infarction and serves as an aid in the diagnosis of infarction.
Adult↗
Recurrent subarachnoid haemorrhages in patient with Hageman factor deficiency.
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Adult↗
[Isotope examination in diagnosis of brain death].
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Brain↗
Radionuclide diagnosis of venous angioma.
Venous angioma is a rare vascular anomaly of the central nervous system. Pathologically, it resembles arteriovenous malformation, but the vascular changes are seen only in the veins. In the present case, the lesion was seen better with dynamic rather than static radionuclide examination. In a computerized dynamic study, the circulation time in the lesion was significantly prolonged compared with the circulation time in the symmetrical area of the contralateral hemisphere. The peak of the time-activity curve also appeared later in the lesion area than in the symmetrical contralateral area. Thus the use of the computerized gamma camera is useful in the diagnosis of venous angioma and the method seems to have some differential diagnostic possibilities.
Adult↗
An intravenous radioisotope method for measuring rCBF and rCBV.
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Adult↗
Correlation of tibial nerve SEPs with the development of seizures in patients with supratentorial cerebral infarcts.
In 40 patients with supratentorial non-haemorrhagic cerebral infarct, the findings in the tibial nerve SEPs recorded during the acute stage correlated significantly with the development of seizures during a 1 year follow-up period. Abnormality in the side-to-side difference of the P40-N48 amplitude was the finding with the highest correlation with the development of seizures: 87.5% of the patients were classified correctly as to the risk of seizures.
Adult↗
A prospective 1 year follow-up study with somatosensory potentials evoked by stimulation of the posterior tibial nerve in patients with supratentorial cerebral infarction.
Somatosensory potentials evoked by stimulation of the posterior tibial nerve (tibial nerve SEPs) were studied in 40 patients with supratentorial non-haemorrhagic cerebral infarction and in 25 control subjects, SEPs were recorded twice in 39 patients and thrice in 35 patients. The first examination was carried out 4-19 days after the onset of the symptoms, the second examination 56-100 days after the stroke, and the third examination 348-393 days after the stroke. Increased side-to-side differences in the P57 and N75 peak latencies and absence of the P40 peak were the most frequent abnormal findings. The latency abnormalities were associated with involvement of the subcortical white matter of the rolandic region. The absence of the P40 peak was, in contrast, closely related to the extension of the infarcted area into the cortical gray matter of the rolandic region. When all SEP abnormalities were taken into account 55% of patients showed at least one abnormality in the tibial nerve SEP during the acute stage, 51% of patients had abnormal SEPs in the second examination and 43% of patients in the third examination. A nearly significant decrease was observed in the number of latency abnormalities, but the number of amplitude abnormalities, including absent responses, did not change during the 1 year follow-up period.
Adolescent↗
Non-invasive external regional measurement of cerebral circulation time changes in supratentorial infarctions using pertechnetate.
A method for measuring regional cerebral circulation time (rCCT) between the hemispheres using intravenous pertechnetate and a multidetector system is presented. Interhemispheric differences of rCCT instead of absolute values were selected because of the variation of pertechnetate bolus dispersion due to changes in the systemic circulation and injection technique inter-and intraindividually. Time activity curves over one minute were analyzed by a modified gamma function fitting method. The results are printed as a brain map which shows reference values and abnormal findings. Abnormal rCCT asymmetry was observed in 10 out of 77 controls (13%) and 58 out of 65 patients with cerebral infarction (89%). Within 2 weeks after a stroke shorter circulation time values on the side of the lesion than on the contralateral side were found in 5 patients. In the severe infarction cases and in the acute stages of infarction circulatory changes could be found in a great number of areas. In patients with manifest diabetes abnormal circulatory findings occurred in larger regions and in a greater number of the patients than in those without that disease. Although the luxury perfusion and diaschisis phenomena, as well as the influence of cross-over of the count rates between the hemispheres, reduce circulatory time differences, use of the present pertechnetate method allows detection of subtle regional circulatory changes in patients with brain infarction.
Adult↗
Cervical headgear therapy as a factor in obstructive sleep apnea syndrome.
PURPOSE: Obstructive sleep apnea syndrome (OSAS) has been a subject of increasing interest from the orthodontic point of view, but less attention has been paid to the possible influence of orthodontic treatment on its occurrence. The aim here was to study possible associations between the use of cervical headgear and nocturnal cessations of airflow and the severity of the latter. METHODS: The subjects were 30 children (12 boys, 18 girls, mean age 8.2, sd 1.61 years), divided into three groups: a group of 10 children undergoing headgear therapy, selected for this examination because of symptoms of OSAS while using headgear, an age-matched control group of 10 healthy children and a group of 10 with OSAS. Standard cephalograms of the headgear group prior to the orthodontic therapy and the corresponding cephalograms of healthy controls were analysed. A polygraphic (PG) sleep evaluation was used to assess the tendency for OSAS. Apnea and hypopnea periods were summated as apnea index (AI) and number of desaturations as desaturation index (ODI). All the subjects spent one night sleeping under laboratory conditions, those with orthodontic treatment spending the first half of the night with the headgear and the latter half without. RESULTS: The position of the mandible was found to be slightly more posterior in the headgear group than in the control group. The children in the headgear group were found to have significantly more apnea/hypopnea periods during the hours when the appliance was used, and the ODI-index showed increased values in this group. CONCLUSIONS: We suggest that headgear therapy may contribute to the occurrence of sleep apnea, when a strong predisposition, such as mandibular retrognathia to the development of upper airway occlusion already exists.
Cephalometry↗