Biomedical subjects

Oliver Wittkugel

Publications and source records attributed to Oliver Wittkugel.

8 recordsLinked to original sources

PubMed2004

MR evaluation of dural ectasia in Marfan syndrome: reassessment of the established criteria in children, adolescents, and young adults.

PURPOSE: To retrospectively evaluate known criteria for assessment of dural ectasia by using magnetic resonance (MR) imaging in children, adolescents, and young adults with and those without Marfan syndrome. MATERIALS AND METHODS: Local ethics committee approval and informed consent were obtained. MR images of the lumbar spine in 28 patients with clinically proved Marfan syndrome (group A; 17 male, 11 female; age range, 4-21 years; mean, 12.1 years), seven patients with suspicion of Marfan syndrome (group B; six male, one female; age range, 6-18 years; mean, 10.4 years), and 55 patients without Marfan syndrome (group C; 26 male, 29 female; age range, 4-20 years; mean, 10.7 years) were evaluated retrospectively for dural ectasia criteria (scalloping, dural sac ratio, nerve root sleeve diameter, sagittal dural sac width at S1 greater than that at L4) and according to classifications by Ahn et al and Fattori et al. For statistical comparison of results, one-way analysis of variance with Scheffe post hoc comparisons was used, with an overall two-tailed significance at alpha = .05. RESULTS: No significant differences in scalloping and nerve root sleeve diameter were shown between groups. A significant difference was measured for dural sac ratios at L5 and S1 (F test, P = .003 and P < .001 at L5 and S1, respectively; post hoc t test for groups A vs C, P = .004 and P < .001 at L5 and S1, respectively). Significant differences were also obtained between groups A and C for sagittal dural sac width at S1 greater than that at L4 according to the calculated mean difference (for both F test and post hoc t test, P < .001 and P = .003 at S1 and L4, respectively). The Ahn et al and Fattori et al classifications were of limited value. CONCLUSION: The data suggest that only dural sac ratio at L5 and S1 and a sagittal dural sac width at S1 greater than that at L4 are statistically significant criteria for the assessment of dural ectasia in children, adolescents, and young adults.

Adolescent↗

PubMed2004

Predictors of apparent diffusion coefficient normalization in stroke patients.

BACKGROUND AND PURPOSE: We sought to describe the frequency of normalization of apparent diffusion coefficient (ADC) values that are decreased in hyperacute stroke and to identify characteristics of tissue demonstrating normalization. METHODS: Sixty-eight acute ischemic stroke patients underwent MRI examination (including diffusion/perfusion imaging and MR angiography) within 6 hours (mean, 2.8 hours) after symptom onset, after 24 hours, and again 4 to 7 days later. Lesion volumes with decreased ADC and delayed time to peak in perfusion imaging were determined. In patients showing ADC normalization, volumes with ADC decrease graded as <50%, 50% to 60%, 60% to 70%, and 70% to 80% of the contralateral value were determined by thresholding. Patients were categorized as normalizers (demonstrating ADC normalization in >5 mL tissue with initially decreased ADC) or nonnormalizers (demonstrating ADC normalization in <5 mL tissue). RESULTS: Fourteen patients (19.7%) were classified as normalizers. Eleven of 31 patients (35.5%) initially imaged <3 hours after stroke onset and 3 of 37 (7.5%) of those imaged 3 to 6 hours after onset were normalizers. ADC normalization occurred predominantly in the basal ganglia and white matter after thrombolytic therapy in patients with more distal vessel occlusions. All normalizers demonstrated at least partial tissue reperfusion. Tissue with more severe initial decrease in ADC was less likely to demonstrate normalization. CONCLUSIONS: ADC normalization is not a rare event in acute stroke after tissue reperfusion. Brain tissue with initially decreased ADC, especially within 3 hours after stroke onset, may include "tissue at risk."

Acute Disease↗

PubMed2004

Bile resistance of coated transjugular intrahepatic portosystemic shunt stents in a flow-model.

PURPOSE: We sought to test the bile resistance of transjugular intrahepatic portosystemic shunt (TIPS) stents with 3 different coatings. MATERIALS AND METHODS: Three stents with different coating materials (monolayer polyethylene terephthalate [PETP], monolayer polytetrafluoroethylene [PTFE], and double layer [PTFE]) were tested in a flow model. After testing the sealing of the system with isotonic saline solution, fresh human bile was circulated. Constant pressure was 50 cm H2O. Bile resistance of the stent membranes was analyzed. RESULTS: Two of the 3 stents proved completely resistant to water. Only the PETP stent was resistant to bile. The PTFE-coated stents were not bile resistant. CONCLUSION: The bile resistance of coated TIPS stents and, thus, the dependency of TIPS shunt patency is called into question. The stent with the reported superior patency rates does not show experimental bile resistance.

Bile↗

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↗

PubMed2004

Huntington disease: a case study of early onset presenting as depression.

Huntington disease is a dominantly inherited, neurodegenerative disease characterized by choreiform movement disturbances and dementia, usually with adult onset. The rare juvenile-onset Huntington disease differs from the adult phenotype. A case presenting twice, at age 10 with all the signs of a major depression and age 14 with mutism and rigidity, is reported. Meanwhile, the father developed the adult variant of Huntington disease. The boy's diagnosis was confirmed by molecular genetic analysis and magnetic resonance imaging. It is important to be aware of hereditary conditions such as Huntington disease and to provide family counseling before genetic testing and after the diagnosis is confirmed.

Adolescent↗

PubMed2003

Endovascular treatment of internal carotid artery stenosis: effect of primary stent application on debris particle release in human cadaveric specimens.

PURPOSE: To compare debris release with primary stent application (self-expanding stent application at stenosis and then balloon dilation through the opened stent) and that with secondary stent application (balloon angioplasty of stenosis and afterward additional stent application) for high-grade internal carotid artery stenosis in human cadaveric specimens. MATERIALS AND METHODS: Fresh human cadaveric internal carotid artery specimens were attached to a tube system. High-grade stenoses (>66%) were selected, randomized for primary or secondary stent application, and then treated, with fluoroscopic guidance, while the system was rinsed in a pulsating flow. Fluid was collected and filtered, and debris particles were examined with a light microscope. Particles were analyzed according to those consecutively caught by 100 x 100-microm and 11 x 11-microm mesh filters. Results were evaluated in relation to stent application. For statistical analyses of group differences, the exact Mann-Whitney U test was used. RESULTS: Thirteen high-grade human cadaveric internal carotid artery stenoses were analyzed. Five specimens were randomly assigned to secondary stent application, and eight were assigned to primary stent application. No significant difference could be demonstrated for debris release with primary or secondary stent application. P values ranged from.051 to.754. CONCLUSION: The reported superiority of primary stent application may not be related to debris reduction.

Arteriosclerosis↗

PubMed2003

Atypical focal MRI lesions in a case of juvenile Alexander's disease.

We present a juvenile case of Alexander's disease with atypical focal magnetic resonance imaging-detected lesions and elevated levels of lactate in cerebrospinal fluid. The diagnosis was based on the neuropathological finding of a diffuse accumulation of Rosenthal fibers within the brain and the spinal cord. The diagnosis was confirmed by detection of a mutation in exon 1 at nucleotide position 249 of glial fibrillary acidic protein cDNA, a finding previously reported in cases of infantile Alexander's disease.

Alexander Disease↗

PubMed2002

Cerebral blood flow predicts lesion growth in acute stroke patients.

BACKGROUND AND PURPOSE: We sought to study the role of MRI-derived cerebral blood flow (CBF) measurements for the prediction of lesion development in acute stroke patients. METHODS: Thirty-two patients were treated with tissue plasminogen activator. Diffusion-weighted (DWI) and perfusion-weighted MRI, T2-weighted imaging, and MR angiography were performed before treatment (2.8+/-0.9 hours after symptom onset) and on follow-up (days 1 and 7). CBF thresholds (12 and 22 mL/100 g per minute) were applied to bolus tracking MRI maps to determine predictive cutoff levels. RESULTS: In 21 patients (group A), the terminal lesion volume (T2-weighted imaging) was larger than the initial DWI lesion volume (89+/-93 versus 21+/-38 mL). In 11 patients (group B), the terminal lesion volume was smaller than the initial DWI lesion volume (7+/-27 versus 15+/-29 mL). The initial DWI lesion volume did not differ between both groups. The presence of a tissue volume > or =50 mL with a CBF value < or =12 mL/100 g per minute was predictive for lesion enlargement to day 7 in T2-weighted imaging (positive predictive value, 0.80). CONCLUSIONS: The presence of a tissue volume > or =50 mL with a CBF value < or =12 mL/100 g per minute predicts further lesion growth in hyperacute stroke patients. MRI-derived CBF values, with all their present limitations, are valuable in early estimation of prognosis of stroke patients.

Acute Disease↗