Biomedical subjects

Einar Goebell

Publications and source records attributed to Einar Goebell.

6 recordsLinked to original sources

PubMed2006

Intravenous administration of acetylsalicylic acid during endovascular treatment of cerebral aneurysms reduces the rate of thromboembolic events.

BACKGROUND AND PURPOSE: The purpose of this study is to analyze the effect of a modified intraoperative anticoagulation strategy including acetylsalicylic acid (ASA) on complication rates during endovascular coil embolization. METHODS: Two hundred and sixty-one cerebral aneurysms were treated in 247 patients by endovascular coil embolization from January 2001 to September 2004. Additional intravenous administration of 250 mg ASA was applied since January 2003. Patients treated before (-ASA; n=102 aneurysms) and after that date (+ASA; n=159 aneurysms) were compared. End points were rates of thromboembolism and severity of hemorrhages after intraoperative aneurysm rupture. RESULTS: Thromboembolic events during the procedure were observed more often in the -ASA group (18/102 aneurysms, 17.6%) in comparison with the +ASA group (14/159 aneurysms, 8.8%; P=0.028; Fisher exact test). Aneurysm perforation events occurring during or immediately after the procedure were observed equally often in the -ASA group (7/102 aneurysms, 6.9%) in comparison with the +ASA group (10/159 aneurysms, 6.3%). CONCLUSIONS: Intravenous application of ASA is feasible and safe during interventional aneurysm embolization. ASA seems to be associated with a significant reduction in the rate of thromboembolic events without increase in the rate or severity of intraoperative bleedings.

Adult↗

PubMed2006

Low-grade and anaplastic gliomas: differences in architecture evaluated with diffusion-tensor MR imaging.

PURPOSE: To prospectively evaluate whether diffusion-tensor magnetic resonance (MR) imaging depicts differences in World Health Organization (WHO) grade II and III glial brain tumors on the basis of tumor architecture and peritumoral tract invasion. MATERIALS AND METHODS: The study protocol was approved by the local ethics committee, and written informed consent was obtained. Diffusion-tensor MR imaging was performed in 23 patients (15 men, eight women; mean age, 47 years) with histologically confirmed brain gliomas. Eleven of the 23 tumors were low-grade gliomas (WHO grade II) and 12 were anaplastic gliomas (WHO grade III). Regions of interest were placed in the tumor center, tumor border, normal-appearing white matter (NAWM) adjacent to the tumor, and NAWM of the contralateral hemisphere. fractional anisotropy (FA) ratios were calculated for regions of interest in relation to the NAWM of the contralateral hemisphere. Pairwise comparisons were performed by using the Mann-Whitney U test. RESULTS: Median FA ratios for grade II versus grade III gliomas were 0.406 versus 0.405, respectively, for tumor center, 0.733 versus 0.449, respectively, for tumor border, and 0.962 versus 0.943, respectively, for NAWM adjacent to the tumor. Differences in FA ratio between low-grade and high-grade tumors were significant in the tumor border only (P = .01). Differences in FA ratio were not significant between low-grade and high-grade gliomas in the tumor center or in the NAWM adjacent to the tumor. CONCLUSION: The periphery of low-grade gliomas contains a considerable amount of preserved fiber tracts. In high-grade gliomas, however, most of these tracts are disarranged. Low FA ratios in the tumor center are consistent with a high degree of disorganization of myelinated fiber tracts in the center of both low-grade and high-grade gliomas.

Adult↗

PubMed2006

Face memory in MRI-positive and MRI-negative temporal lobe epilepsy.

PURPOSE: Effects of MRI-positive (MRI(+)) as compared to MRI-negative (MRI(-)) temporal lobe epilepsy (TLE) on face memory are not yet known. METHODS: We studied 24 MRI(-) (11 right/13 left) and 20 MRI(+) (13 right/7 left) TLE patients, 12 generalized epilepsy patients, and 12 healthy subjects undergoing diagnostic workup with 24-72-h Video-EEG-monitoring. Twenty faces were shown, and had to be recognized from 40 faces immediately and after a 24-h delay. RESULTS: MRI(+) and MRI(-) right TLE (RTLE) patients showed deficits in face recognition compared to controls or generalized epilepsy, consistent with right temporal lobe dominance for face recognition. MRI(+) RTLE patients had deficits in both immediate and delayed recognition, while MRI(-) RTLE patients showed delayed recognition deficits only. The RTLE groups showed comparable delayed recognition deficits. Separate analyses in which the MRI(+) group included patients with hippocampal sclerosis only, did not alter results. Furthermore, MRI(-) RTLE had a worse delayed recognition than MRI(-) left TLE (LTLE). On the other hand, MRI(+) RTLE did not differ from MRI(+) LTLE in delayed recognition. Combining MRI(-) and MRI(+) TLE groups, we found differences between RTLE and LTLE in delayed, but not immediate face recognition. CONCLUSIONS: Our results suggest that a delayed recognition condition might be superior to immediate recognition tests in detecting face memory deficits in MRI(-) RTLE patients. This might explain why former studies in preoperative patients did not observe an immediate face recognition dominance of the right temporal lobe when combining MRI(-) and MRI(+) TLE patients. Our data further point to an important role of the right mesial temporal region in face recognition in TLE.

Epilepsy, Temporal Lobe↗

PubMed2005

Vascular occlusion sites determine differences in lesion growth from early apparent diffusion coefficient lesion to final infarct.

BACKGROUND AND PURPOSE: Occlusion of major cerebral arteries is the primary source of tissue damage in ischemic stroke and the target of thrombolytic therapy. We hypothesized that large infarcts in more proximal vascular occlusions correspond with substantially increased ischemic lesions shown on initial apparent diffusion coefficient (ADC) maps. METHODS: Initial ADC lesions in 120 patients with acute ischemic stroke were analyzed within 6 hours of stroke onset. Patients were categorized on the basis of vascular occlusion, as shown on MR angiography. Lesion volumes were determined by using manual delineation (ADC(man)) and a threshold method for ADC values (<550 x 10(-9) mm(2)/s(-1), ADC(<550)). Infarct volumes were analyzed by using T2-weighted (n = 109) or CT (n = 11) images obtained on days 5-8. RESULTS: Median lesion volumes for ADC(<550), ADC(man), and infarcts, respectively, were as follows: proximal internal carotid artery (ICA)/middle cerebral artery (MCA) occlusions, 10, 23, and 32 cm(3); carotid-T occlusions, 11, 37, and 138 cm(3); MCA trunk occlusions, 11, 27, and 44 cm(3)); and MCA branch occlusions 8, 27, and 21 cm(3). Initial ADC lesion volumes were different only between the carotid T and the MCA branch (P < .05). On days 5-8, infarct volumes decreased from proximal to distal sites (P < .05), with the exception of MCA trunk versus proximal ICA/MCA occlusions. Recanalization rate in carotid-T occlusion was significantly lower than those of all other occlusion types. CONCLUSION: Initial ADC lesions can be small, even in patients with proximal vascular occlusions. These patients develop considerably large infarctions, suggesting a high potential for infarct growth. This growth might be averted with improved early recanalization of proximal vascular occlusions.

Arterial Occlusive Diseases↗

PubMed2004

Screening for cerebellopontine angle tumors: is a CISS sufficient?

This study attempted to evaluate the reliability of ultra-thin T2-weighted imaging with a constructive interference in steady state (CISS) sequence as a screening method for tumors in the cerebellopontine angle. A retrospective study of 200 CISS examinations was made by five investigators. The examinations were inspected on plain film supported by clinical information. The interobserver agreement in the detection of lesions was analyzed. Fourteen cases (50% of the contrast-enhancing lesions) were rated pathological by all five readers. One case of subarachnoid lymphoma infiltration was overlooked by all five readers. Overall, six pathological lesions (median = 6, range 1-9) were not identified. The interobserver agreement for all pathological lesions was moderate (kappa=0.53; 95% CI, 0.43-0.62). The mean sensitivity was 77.8% (range 72.0-96.3%), and the mean specificity was 97.6% (range 94.8-100%). The median sensitivity for pathological lesions concerning only patients with acute sensorineural hearing loss (n=148, patients with 20 contrast-enhancing cases) was 86.6% (range 80-100%), and median specificity was 95.2% (range 84.4-96.9%) with a moderate interobserver agreement (kappa=0.55; 95% CI, 0.44-0.66). In our opinion the CISS sequence is a valuable addition to the examination of the cerebellopontine angle but lacks sufficient reliability for the detection of tumors of small size or of tumors adjacent to brain parenchyma or the temporal bone.

Cerebellar Neoplasms↗

PubMed2004

Normal brain maturation characterized with age-related T2 relaxation times: an attempt to develop a quantitative imaging measure for clinical use.

OBJECTIVES: We studied age-related changes in T2 relaxation times from the normal maturating human brain under routine clinical MR examination conditions. MATERIALS AND METHODS: In 70 healthy subjects aged between 3 weeks and 39 years, T2 maps of the brain in which the intensity of each pixel corresponded to T2 relaxation times were generated based on magnetic resonance imaging data collected with a triple spin echo sequence. T2 relaxation times in white matter (WM) and gray matter (GM) were measured in 6 distinctive regions of interest of the T2 maps. The age dependence of the T2 values was mathematically simulated using a biexponential function. RESULTS: T2 values were largest at the age of 3 weeks (maximum: approximately 400 milliseconds for WM and 200 milliseconds for GM) and decreased continuously with increasing age, faster in the first few months and slower thereafter, until values achieved between 95 and 110 milliseconds for WM and 88 and 95 milliseconds for GM in adults. The relationship between T2 values and age could be well simulated using a biexponential function (R > 0.92). CONCLUSIONS: T2 relaxation time correlates well with the progress of brain maturation. The used biexponential function reflects the dynamic development of myelination in newborns and young children as well as the maturation of myelination during adolescence and could be used to develop a "normal" reference for neuroradiological diagnoses.

Adult↗