Biomedical subjects

Carsten Gyldensted

Publications and source records attributed to Carsten Gyldensted.

6 recordsLinked to original sources

PubMed2006

[Diagnostic imaging in dementia evaluation].

INTRODUCTION: The aim of the study was to evaluate the changes in diagnoses and treatment by structural scanning in dementia evaluation. MATERIAL AND METHODS: 336 elderly, consecutively evaluated patients from two university memory clinics (mean age 75 y, mean MMSE 21.7), were retrospectively diagnosed without and with inclusion of scan results. These results were compared to prospective data obtained from 137 patients scanned as part of a population based study (The Odense Study, mean age 78.5, mean MMSE 23.3). CT and MRI were performed in 93% and 7% of the patients, respectively. RESULTS: Potentially reversible structural pathology was found in 3.5% of the memory clinic patients, and in 2% of the population based patients. By applying international diagnostic criteria and treatment recommendations to the retrospective memory clinic data, it was found that adding a structural scan changed diagnoses and treatment in 37% and 33% of the patients, primarily due to identification of cerebrovascular disease (CVD) in patients with no clinical signs or symptoms of CVD. In comparison, the change in diagnosis found in the prospective population data was lower (15%). It was not possible to identify a group of patients that would not benefit from scanning. CONCLUSION: Our data support recent guidelines that suggest CT scan as a routine investigation in dementia evaluation.

Aged↗

PubMed2005

Ischemic injury detected by diffusion imaging 11 minutes after stroke.

A 78-year-old woman suffered a stroke inside a magnetic resonance scanner while being imaged because of a brief transient ischemic attack 2 hours earlier. Diffusion-weighted images obtained 11 minutes after stroke showed tissue injury not found on initial images. The data show early, abrupt diffusion changes in hypoperfused tissue, adding to our understanding of the progression of microstructural abnormalities in the hyperacute phase of stroke.

Aged↗

PubMed2004

Do indomethacin and propofol cause cerebral ischemic damage? Diffusion-weighted magnetic resonance imaging in patients undergoing craniotomy for brain tumors.

BACKGROUND: Diffusion-weighted magnetic resonance imaging was used to determine whether indomethacin and propofol induce cerebral ischemic damage in patients undergoing craniotomy for cerebral tumors. As a secondary aim, the authors investigated whether low jugular bulb oxygen saturation values were associated with brain parenchymal damage as evaluated by diffusion-weighted imaging. METHODS: Nine patients subjected to craniotomy for supratentorial brain tumors in propofol-fentanyl anesthesia were studied. Magnetic resonance imaging including diffusion- and perfusion-weighted and structural sequences were performed (1) on the day before surgery, (2) before and (3) 20 min after administration of indomethacin (bolus of 0.2 mg/kg followed by infusion of 0.2 mg.kg.h) in the propofol-fentanyl-anesthetized patient, and (4) 2 days after surgery. Apparent diffusion coefficient maps were calculated. Jugular bulb oxygen saturation, arteriovenous oxygen difference, mean arterial blood pressure, and arterial oxygen and carbon dioxide tensions were measured simultaneously with the magnetic resonance examinations performed during anesthesia. RESULTS: No ischemic lesions were detected in the diffusion-weighted or apparent diffusion coefficient images. A nonsignificant decrease in jugular bulb oxygen saturation from 51% (range, 40-61%) to 43% (range, 37-63%) and increase in arteriovenous oxygen difference from 4.4 mm (range, 2.7-4.6 mm) to 4.7 mm (range, 2.9-5.2 mm) was observed after indomethacin administration. CONCLUSION: Administration of indomethacin during propofol anesthesia is not associated with evidence of ischemic damage in patients with brain tumors, as evaluated by diffusion-weighted imaging.

Adult↗

PubMed2002

Time evolution of cerebral perfusion and apparent diffusion coefficient measured by magnetic resonance imaging in a porcine stroke model.

PURPOSE: To demonstrate the feasibility of sequential diffusion-weighted (DW) and perfusion-weighted (PW) magnetic resonance imaging (MRI) of a recently developed porcine stroke model and to evaluate the evolution of cerebral perfusion and the apparent diffusion coefficient (ADC) over time. Materials and Methods In five pigs, DW imaging (DWI) and PW imaging (PWI) was carried out for 7 hours after stroke onset, starting 1 hour after middle cerebral artery occlusion (MCAO). RESULTS: The DWI lesion volume increased significantly with time, and final DWI lesion volume correlated well with lesion area on histological sections (r = 0.910). T2 changes could be recognized 3 hours after stroke onset. At 1 hour the ADC ratio (ischemic lesion/contralateral side) was reduced to 0.81 in the caudate-putamen and to 0.87 in the cortex, and the cerebral blood flow ratio was reduced to 0.40 in the caudate-putamen and 0.51 in the cortex. CONCLUSION: The level of flow reduction in the caudate-putamen and the cortex after 1 hour is in good correlation with human thresholds of irreversible and reversible ischemic damage, and accordingly, this model might be a model for mechanisms of infarct evolution and therapeutic intervention.

Analysis of Variance↗

PubMed2002

Blood flow and ischemia within traumatic cerebral contusions.

OBJECTIVE: To provide evidence of irreversible ischemia in cerebral contusions among patients with severe traumatic brain injuries and to clarify the potential viability of tissue in the pericontusional zone, quantitative regional cerebral blood flow (rCBF) measurements obtained with the xenon-enhanced computed tomographic method were correlated with the areas of contusions, by using image fusion. METHODS: rCBF measurements obtained during the acute phase (mean, 2 d after injury; range, 0-10 d) were statistically correlated with the extent of tissue necrosis identified as focal atrophy on late follow-up computed tomographic scans (mean time after the xenon-enhanced computed tomographic cerebral blood flow investigation, 265 d; range, 30-1047 d). RESULTS: Seventeen patients exhibited 26 traumatic contusions. All contusions progressed to late focal atrophic areas on the follow-up computed tomographic scans. The rCBF values within the traumatic contusions ranged from 0.5 to 22.0 ml/100 g/min, with a mean of 5.9 +/- 5.9 ml/100 g/min. The contusions exhibited a specific rCBF profile, presenting as a core of severe lethal ischemia surrounded by variable but gradually increasing perfusion with increasing distance from the ischemic core. CONCLUSION: The ischemic profile of the contusions, with a pericontusional zone of low rCBF, presents the potential risk of secondary ischemic insults, similar to the risk in the ischemic penumbral zones surrounding areas of acute ischemic stroke.

Adolescent↗

PubMed2002

Final infarct size after acute stroke: prediction with flow heterogeneity.

PURPOSE: To compare acute measurements of flow heterogeneity (FH) and mean transit time (MTT) with follow-up data to determine which method yields better predictive measures of final infarct volumes. MATERIALS AND METHODS: Twenty-three patients with symptoms of stroke underwent magnetic resonance (MR) imaging during the acute stage, and the tissue at risk was estimated from MTT maps and maps generated by means of detecting abnormal FH. Final infarct volumes were calculated from T2-weighted follow-up MR image measurement. The Wilcoxon signed rank test was performed to compare the two predictive maps (MTT and FH) with T2-weighted follow-up maps. RESULTS: Eleven (48%) patients experienced infarct growth. Both the MTT and the FH maps enabled prediction of 10 of these cases. There were five false-positive cases with MTT measurement but three with FH measurement. In terms of predicting final infarct volumes, the final infarct size on the MTT maps was overestimated by 75%. The final infarct size on the FH maps also was overestimated, but by only 15%. MTT map measurements were significantly different from follow-up MR image measurements (P =.005), but FH map measurements were not (P =.059). CONCLUSION: FH maps may enable more precise prediction of final infarct volume in stroke patients.

Acute Disease↗