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Biomedical subjects

H Brückmann

Publications and source records attributed to H Brückmann.

At least 19 recordsLinked to original sources
PubMed2006

Effects of treatment with the atypical neuroleptic quetiapine on working memory function: a functional MRI follow-up investigation.

BACKGROUND: Working memory as a part of higher-order executive functions is defined by the parallel storage and processing of information. Recent functional fMRI studies have revealed a functional, interregional disintegration of a neuronal network connecting cortical, subcortical and cerebellar regions in schizophrenic patients (SZ). Cognitive impairment in working memory is a core psychopathological correlate of schizophrenic symptoms. Atypical neuroleptics such as quetiapine have shown good efficacy in treating positive and negative symptoms. The presented study evaluated the impact of a neuroleptic steady state treatment with quetiapine on the altered working memory activation patterns in schizophrenia. METHODS: Patients were examined by fMRI at baseline and after 12 weeks of steady state treatment with quetiapine. Matched healthy controls (HC) underwent baseline examination. In the scanner, stimuli were presented in a 2-back and 0-back condition of a working memory (wm) paradigm, whereby a degraded and a non-degraded version were used each time. Additionally, behavioural responses (reaction time to target stimuli and error ratio) were measured. RESULTS: At baseline, healthy controls revealed increased activity in the frontal lobe, especially in regions of the prefrontal cortex. Compared to HC, SZ showed hypoactivation in the right dorsolateral prefrontal cortex (DLPFC) and the ventrolateral prefrontal cortex (VLPFC) bilaterally for the 2-back condition. In the 2-back degraded condition there was a hypoactivation in both, the right DLPFC and the VLPFC. Additionally, patients showed bilaterally decreased activation in the basalganglia in the 2-back and in the right caudatus in the 2-back degraded condition compared to healthy controls. After treatment with quetiapine, patients activations patterns were increased. The pre-post comparison of the 2-back condition revealed a significant increase of activation in the left VLPFC at a significance level of 0.001 (uncorrected). The 2-back degraded condition led to a significant activation pattern in the lingual gyrus and the right precuneus. In both wm conditions, at baseline there were no differences in reaction time but only a worse performance in SZ. After treatment, behavioural measurement of responses, including reaction time and performance, showed slight improvements in SZ, although these did not reach statistical significance. CONCLUSIONS: The neuronal networks underlying working memory are clearly altered in schizophrenia. After 12 weeks of treatment with quetiapine monotherapy, patients showed significant clinical improvement and revealed increased BOLD activity in the VLPFC during a working memory task, although there was no improvement of cognitive performance.

Adult↗
PubMed2006

30 day results from the SPACE trial of stent-protected angioplasty versus carotid endarterectomy in symptomatic patients: a randomised non-inferiority trial.

BACKGROUND: Carotid endarterectomy is effective in stroke prevention for patients with severe symptomatic carotid-artery stenosis, and carotid-artery stenting has been widely used as alternative treatment. Since equivalence or superiority has not been convincingly shown for either treatment, we aimed to compare the two. METHODS: 1200 patients with symptomatic carotid-artery stenosis were randomly assigned within 180 days of transient ischaemic attack or moderate stroke (modified Rankin scale score of < or =3) carotid-artery stenting (n=605) or carotid endarterectomy (n=595). The primary endpoint of this hospital-based study was ipsilateral ischaemic stroke or death from time of randomisation to 30 days after the procedure. The non-inferiority margin was defined as less than 2.5% on the basis of an expected event rate of 5%. Analyses were on an intention-to-treat basis. This trial is registered at Current Controlled Trials with the international standard randomised controlled trial number ISRCTN57874028. FINDINGS: 1183 patients were included in the analysis. The rate of death or ipsilateral ischaemic stroke from randomisation to 30 days after the procedure was 6.84% with carotid-artery stenting and 6.34% with carotid endarterectomy (absolute difference 0.51%, 90% CI -1.89% to 2.91%). The one-sided p value for non-inferiority is 0.09. INTERPRETATION: SPACE failed to prove non-inferiority of carotid-artery stenting compared with carotid endarterectomy for the periprocedural complication rate. The results of this trial do not justify the widespread use in the short-term of carotid-artery stenting for treatment of carotid-artery stenoses. Results at 6-24 months are awaited.

Aged↗
PubMed2006

Eye closure in darkness animates olfactory and gustatory cortical areas.

In two previous fMRI studies, it was reported that eyes-open and eyes-closed conditions in darkness had differential effects on brain activity, and typical patterns of cortical activity were identified. Without external stimulation, ocular motor and attentional systems were activated when the eyes were open. On the contrary, the visual, somatosensory, vestibular, and auditory systems were activated when the eyes were closed. In this study, we investigated whether cortical areas related to the olfactory and gustatory system are also animated by eye closure without any other external stimulation. In a first fMRI experiment (n = 22), we identified cortical areas including the piriform cortex activated by olfactory stimulation. In a second experiment (n = 12) subjects lying in darkness in the MRI scanner alternately opened and closed their eyes. In accordance to previous studies, we found activation clusters bilaterally in visual, somatosensory, vestibular and auditory cortical areas for the contrast eyes-closed vs. eyes-open. In addition, we were able to show that cortical areas related to the olfactory and gustatory system were also animated by eye closure. These results support the hypothesis that there are two different states of mental activity: with the eyes closed, an "interoceptive" state characterized by imagination and multisensory activity and with the eyes open, an "exteroceptive" state characterized by attention and ocular motor activity. Our study also suggests that the chosen baseline condition may have a considerable impact on activation patterns and on the interpretation of brain activation studies. This needs to be considered for studies of the olfactory and gustatory system.

Attention↗
PubMed2006

[Diagnosis and therapy of basilar artery occlusion].

In view of the poor prognosis for untreated patients with basilar artery occlusion, rapid delivery of effective treatment has the highest priority. Early recanalization by intra-arterial thrombolysis can improve the outcome in some patients. Apart from this method, specialized centers are increasingly using mechanical devices and glycoprotein IIb/IIIa inhibitors to achieve recanalization. This review focuses on current developments in the diagnosis and treatment of acute basilar artery occlusion.

Cerebral Angiography↗
PubMed2006

[Imaging techniques in diagnosis of brainstem infarction].

Twenty per cent of cerebral ischaemic infarctions involve tissue, supplied by the vertebrobasilar circulation. This overview of the current literature and our own experiences present the value of different imaging techniques (CT and MRI) and new developments for diagnosing brainstem infarction. Furthermore, the roles of invasive and noninvasive vascular imaging methods (computed tomographic angiography, magnetic resonance angiography, intra-arterial angiography, ultrasound) for evaluating vertebrobasilar stenosis and occlusion are described. The diagnostic workup of the most severe form of brainstem infarction, basilar artery thrombosis, is shown.

Brain Stem Infarctions↗
PubMed2006

[Lysis therapy vs. conservative therapy: randomised and prospective study on the treatment of acute central retinal artery occlusion (EAGLE study)].

In the prospective, randomised and multicenter EAGLE study, the therapeutic efficiency of local intra-arterial fibrinolysis (LIF) versus conservative treatment is being tested in patients with an acute central retinal artery occlusion (CRAO). The most important inclusion criteria are: (1) age between 18-75 years, (2) CRAO not older than 20 h, and (3) visual acuity <0.32. The primary study endpoint is the visual acuity before and 1 month after therapy. The study was started in 2002. To August 2006, 63 of the 200 required patients have been included in the study at 17 medical centers in Germany, Switzerland and Austria.

Europe↗
PubMed2004

Congested residual nidus after preoperative intranidal embolization in midsize cerebral arteriovenous malformations of 3-6 cm in diameter.

BACKGROUND: Modern delicate microcatheters allow intranidal embolization of cerebral arteriovenous malformations (AVM). The aim of the current analysis was to assess effects of preoperative intranidal deployment of embolic material on surgical time and blood loss in cerebral arteriovenous malformations of 3-6 cm in diameter. METHODS: The case records of 38 cerebral AVM between 3 and 6 cm in maximum diameter were reviewed, that had been embolized intranidally with N-butyl 2-cyanoacrylate (Histacryl) and subsequently operated on. Surgical time and blood loss as well as particular intraoperative findings such as a congested nidus and thrombosis of draining veins were registered and correlated with the extent of embolization and the time interval between embolization and surgery. FINDINGS: Preoperative embolization occluded an estimated range of 10 to 90% of the nidus. Minor embolization related bleeding without clinical relevance occurred in 5 patients. Significant embolization related bleeding resulting in earlier than planned surgery occurred in another 5 patients. All embolization related haemorrhages occurred within 24 hours. Average total operating time was 343+/-106 min and average blood loss was 684+/-858 ml. Unequivocal bleeding difficulty from the nidus and a total blood loss of more than 1000 ml were encountered in 7 instances and dissection was tedious due to a bleeding AVM core in 5 other cases. A congested AVM core was the source of bleeding in 11 patients and paraventricular neovascularization in one. 6 of the 11 cases with a congested AVM core had suffered minor or substantial haemorrhage after a preoperative endovascular procedure. Intraoperative nidus congestion was noted in this series after an interval as long as 2 weeks after the last embolization. Combined management resulted in permanent morbidity in 6 of the 38 cases. In 4 of them the neurological deficit was associated with an intraoperative bleeding problem, in all due to congested nidus. Morbidity had to be correlated with major haemorrhage resulting from preoperative embolization in 2 instances. CONCLUSIONS: Intranidal embolization prior to surgical removal of AVM can lead to a congested residual nidus and intraoperative bleeding. Minor leakage after preoperative embolization is an inconsistent warning sign of nidus congestion. Nidus outflow after intranidal embolization appears to require a few weeks for normalization. Delay of surgery after embolization should be considered in cases of suspected congested residual nidus. The danger of major haemorrhage or arterial revascularization during this waiting period appears small.

Blood Loss, Surgical↗
PubMed2004

[Magnetic resonance imaging of subarachnoid hemorrhage].

Computed tomography (CT) is the method of choice to detect acute subarachnoid hemorrhage (SAH). The sensitivity of CT has been reported to range from 85 to 100 %. Magnetic resonance imaging (MRI) using FLAIR sequences shows a comparable sensitivity in acute SAH and in some cases can even be superior to CT. However, additional proton density weighted (PDW) TSE sequences or 3D-FLAIR sequences should be used to avoid false-positive results caused by flow artifacts. Conventional T (1)- or T (2)-weighted SE sequences or susceptibility weighted T (2)* or EPI sequences used for the diagnosis of intracerebral hemorrhage do not detect SAH reliably enough. In subacute SAH, starting from day 5 after the suspected hemorrhage, the sensitivity of MRI is clearly superior to CT. Patients with suspected ischemic stroke scheduled for the initial evaluation by MRI no longer need additional CT studies to rule out subarachnoid hemorrhage as long as the MRI protocols are adequate and the radiologist has the necessary experience.

Acute Disease↗
PubMed2003

Combined cerebellar and bilateral cervical posterior spinal artery stroke demonstrated on MRI.

Combined cerebellar and spinal ischemic stroke is a rare, critical condition. We report a patient with combined cerebellar and bilateral posterolateral cervical spinal cord infarction due to bilateral stenosis of the vertebral arteries. MRI is the method of choice for imaging this condition; diffusion-weighted imaging of the spinal cord gives reliable results.

Cerebellar Diseases↗
PubMed2001

Detection of hyperacute parenchymal hemorrhage of the brain using echo-planar T2*-weighted and diffusion-weighted MRI.

We investigated the usefulness of echo-planar imaging (EPI) as well as T2*-weighted and diffusion-weighted MRI (DWI) to identify hyperacute hemorrhage (within 24 h after ictus) in the brain. Seven patients were examined 3.5 to 24 h after onset of symptoms using a whole-body 1.5-T MR system. Two diffusion-weighted sequences were run to obtain isotropic and anisotropic diffusion images. Apparent diffusion coefficients (ADC) were calculated from the isotropic diffusion images. All DWI images as well as the T2*-weighted EPI images showed the hematomas as either discrete, deeply hypointense homogeneous lesions, or as lesions of mixed signal intensity containing hypointense areas. We conclude that even in the early phase after hemorrhage, sufficient amounts of paramagnetic deoxyhemoglobin are present in intracerebral hemorrhages to cause hypointensity on EPI T2*-weighted and DWI images; thus, use of ultrafast EPI allows identification of intracerebral hemorrhage.

Acute Disease↗
PubMed2000

Rotational vertebral artery occlusion syndrome with vertigo due to "labyrinthine excitation".

Leftward head rotations in a patient with a rotational vertebral artery occlusion syndrome elicited recurrent uniform attacks of severe rotatory vertigo and tinnitus in the right ear. These attacks were accompanied by a mixed clockwise torsional downbeat nystagmus with a horizontal component toward the right. A transient ischemia of the right labyrinth probably induced the attacks and led to a combined transient excitation of the right anterior and horizontal semicircular canals as well as the cochlea.

Angiography, Digital Subtraction↗
PubMed2000

Serial CT and MRI of ischaemic cerebral infarcts: frequency and clinical impact of haemorrhagic transformation.

The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80%. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size (P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred.

Adolescent↗
PubMed2000

Visualization of cranial nerves I-XII: value of 3D CISS and T2-weighted FSE sequences.

The aim of this study was to evaluate the sensitivity of the three-dimensional constructive interference of steady state (3D CISS) sequence (slice thickness 0.7 mm) and that of the T2-weighted fast spin echo (T2-weighted FSE) sequence (slice thickness 3 mm) for the visualization of all cranial nerves in their cisternal course. Twenty healthy volunteers were examined using the T2-weighted FSE and the 3D CISS sequences. Three observers evaluated independently the cranial nerves NI-NXII in their cisternal course. The rates for successful visualization of each nerve for 3D CISS (and for T2-weighted FSE in parentheses) were as follows: NI, NII, NV, NVII, NVIII 40 of 40 (40 of 40), NIII 40 of 40 (18 of 40), NIV 19 of 40 (3 of 40), NVI 39 of 40 (5 of 40), NIX, X, XI 40 of 40 (29 of 40), and NXII 40 of 40 (4 of 40). Most of the cranial nerves can be reliably assessed when using the 3D CISS and the T2-weighted FSE sequences. Increasing the spatial resolution when using the 3D CISS sequence increases the reliability of the identification of the cranial nerves NIII-NXII.

Adult↗
PubMed2000

Three-dimensional reconstructed rotational digital subtraction angiography in planning treatment of intracranial aneurysms.

We evaluated three-dimensional (3D) reconstructions of 200 degrees rotational digital subtraction angiography (DSA) images for their contributions to improving the safety of endovascular embolization of intracranial aneurysms. Standard DSA and 200 degrees rotational DSA were performed in 40 adult patients (aged 21-77 years) with 45 intracranial aneurysms. Information obtainable from standard DSA and 3D-DSA images about aneurysm shape and size was compared. In 40 (89%) of the 45 aneurysms 3D-DSA gave additional information about the anatomy of the aneurysm. In 17 (43 %) of these cases aneurysm anatomy could be visualized better on 3D-DSA than on standard DSA images. In three cases only 3D-DSA images showed blood vessels originating from the aneurysm. Reconstructed 3D images were also helpful in visualizing partially clipped aneurysms. On maximum-intensity projection images it was even possible to depict previously embolized aneurysms. Blood vessels originating from the aneurysm are visible on 3D-DSA images, and even previously clipped aneurysms can be visualized well. Rotational DSA with 3D reconstruction is a helpful tool in the assessment of intracranial aneurysms.

Adult↗
PubMed2000

Usefulness of 3-D reconstructed images of the human cerebral cortex for localization of subdural electrodes in epilepsy surgery.

Three-dimensional (3-D) images of 14 patients, in whom subdural electrodes were implanted for epilepsy surgery evaluation, were produced by fusing computerized tomography (CT) scans and magnetic resonance images (MRI) to determine the exact location of the electrodes. In 25% (198 of 806) of the subdural electrodes an exact location for resection strategy was not evident from the X-rays. The location of these electrodes ('doubtful location', DL) was compared to the 3-D images. Intraoperative inspection served as the gold standard. Concordance score was defined as good for 75-100% concordance, moderate for 50-75%, and poor for less than 50% concordance of the DL electrodes to the intraoperatively determined location. A comparative analysis of the 3-D images and X-ray films showed a highly significant difference (P < 0.0002) in favor of 3-D images. The concordance score for the DL electrodes in the 3-D images was good in 93% of the patients and moderate in 7%. In contrast, the concordance score was good in only 7% of the patients for the two-dimensional (2-D) skull films, moderate in 57%, and poor in 36%. Interobserver reliability was better for 3-D images (93%) than for the 2-D X-rays (43%). These findings suggest that 3-D images aid preoperative planning for resective epilepsy surgery.

Adolescent↗
PubMed1999

[Progressive multifocal leukoencephalopathy as a result of immunosuppressive therapy].

HISTORY AND ADMISSION FINDINGS: A 62-year-old woman developed paresis in her right arm within several weeks. She was being treated with methylprednisolone (4 mg daily) and chlorambucil (2 mg every other day) for systemic lupus erythematodes (SLE), which was now in remission. Neurological examination on admission revealed a right flaccid hemiparesis, predominantly of the right arm. The physical examination was otherwise unremarkable. INVESTIGATIONS: Magnetic resonance imaging (MRI) (T2 weighted) showed hyperintense changes in the subcortical medullary layer of the left precentral gyrus without perifocal oedema or abnormal contrast medium uptake, which argued against progressive cerebral ischaemia or tumour. Blood and cerebrospinal fluid (CSF) showed no abnormalities except leukopenia and a raised antinuclear antibody titre. Progressive paralysis of the right side of the body after 2 years of immunosuppressive treatment, the MRI findings and an essentially normal CSE suggested progressive multifocal leucoencephalopathy (PML), confirmed by polymerase chain reaction (PCR) demonstrating JC-virus DNA in serum and CSF. TREATMENT AND COURSE: As a result of the CNS infection with papovavirus JC, an opportunistic infection of the central nervous system, which is usually fatal, occurred. The cerebral changes spread within a few weeks, despite of the immunosuppressive drugs having been discontinued. The pareses progressed further and a marked personality disorder of organic origin ensued. CONCLUSION: While efficacious immunosuppressive drugs against autoimmune disease are available, their use risks the occurrence of life-threatening opportunistic infections.

Brain↗