PubMed Health⌕ Search

Biomedical subjects

M Forsting

Publications and source records attributed to M Forsting.

At least 127 records · Page 7Linked to original sources
PubMed1995

Does arterial recanalization improve outcome in carotid territory stroke?

BACKGROUND AND PURPOSE: We sought to determine whether early (< 8 hours) or delayed (8 to 24 hours) recanalization after stroke may be an independent variable in the improvement of clinical outcome in patients with occlusion of the middle cerebral artery. METHODS: We prospectively studied 77 patients by combined Scandinavian Stroke Scale score at admission, repeated computed tomography and angiography before and after thrombolytic treatment at < 8 hours after stroke onset, and transcranial Doppler ultrasound 24 hours later. We tested an association between clinical and neuroradiological baseline characteristics, recanalization, and outcome as assessed by the modified Rankin Scale 4 weeks after stroke and determined the effect of recanalization on mortality and good outcome (Rankin Scale grades 0 to 3) by multiple logistic regression analyses. RESULTS: Recanalization rates at 8 and 24 hours after stroke correlated with sites of occlusion (middle cerebral artery branch, 73% and 73%, trunk, 27% and 38%, respectively; intracranial internal carotid artery bifurcation, 14% and 14%; P = .002), collaterals (good, 43% and 51%, respectively; scarce, 17% and 19%, respectively; P = .01), and Scandinavian Stroke Scale score at admission (P = .002). Six of 6 patients with delayed recanalization had good outcomes. Recanalization at < 8 hours after symptom onset had no independent predictive value for good outcome (P = .69). Recanalization at 24 hours increased the proportion of good outcomes from 23% to 75% in a subgroup of patients. Recanalization did not independently affect mortality (P > .15). CONCLUSIONS: Even if delayed, arterial recanalization may improve clinical outcome in a subgroup of patients with middle cerebral artery occlusion.

Adult↗
PubMed1995

Clinical and biochemical analysis in infection-associated stroke.

BACKGROUND AND PURPOSE: Currently, recent infection (primarily bacterial infection) is discussed as a risk factor for cerebrovascular ischemia. The aim of this study was to investigate whether the association of ischemic stroke with recent infection is restricted to stroke subtypes and whether recent infection influences the severity of the postischemic deficit; we also aimed to define biochemical pathways linking infection and ischemic stroke. METHODS: Analyzing the data of a prospective case-control study, we classified the etiology of cerebrovascular ischemia on the basis of clinical, neuroradiological, sonographical, cardiological, and biochemical data in 159 patients without and in 38 patients with infection within 1 week before ischemia. We assessed the severity of neurological deficits using the Scandinavian Stroke Scale. RESULTS: In patients with recent infection compared with patients without infection, the neurological deficit on admission was more severe (median of scores, 41 versus 30.5; P < .005), cortical infarcts in the middle cerebral artery territory were more frequent (60% versus 26%; P < .001), the prevalence of extracranial artery stenoses was lower (9% versus 26%; P < .05), and definite or presumed cardioembolic stroke was more frequent (34% versus 19%; P < .05), as was stroke from cervical artery dissection (8% versus 1.3%; P = .05). Serum levels of C-reactive protein were higher in patients with (20.7 +/- 26.8 mg/L) than in those without infection (9.2 +/- 23.7 mg/L; P < .01). CONCLUSIONS: Recent infection may be associated with a more severe postischemic deficit and with an increased risk of stroke from cardioembolic origin and from cervical arterial dissection.

Adolescent↗
PubMed1995

Early MR detection of experimentally induced cerebral ischemia using magnetic susceptibility contrast agents: comparison between gadopentetate dimeglumine and iron oxide particles.

PURPOSE: To evaluate early patterns of MR changes in a rat model of cerebral ischemia using the first pass of two magnetic susceptibility contrast agents. METHODS: One hours after endovascular middle cerebral artery occlusion, all animals were examined in an experimental MR unit. After bolus application of gadopentetate dimeglumine and, 10 minutes later, of iron oxide particles, the MR changes of the first pass of these contrast agents were followed using a T2*-weighted fast low-angle shot sequence. Time-density curves of both contrast agents were analyzed and compared. RESULTS: After bolus injection of either (paramagnetic) gadopentetate dimeglumine or superparamagnetic particles, nonischemic brain parenchyma decreased markedly in signal, whereas the ischemic brain area remained relatively hyperintense (and thus became clearly delineated). Only after application of gadopentetate dimeglumine did a mild reduction in signal occur in the ischemic hemisphere, although the main artery was occluded. An explantation for this phenomenon might be residual capillary perfusion (plasma flow), which is detectable only when the smaller (paramagnetic) contrast molecules are being used. CONCLUSIONS: Cerebral perfusion deficits can be detected 1 hour after vascular occlusion with T2*-weighted fast low-angle shot sequences and bolus injection of paramagnetic or superparamagnetic MR contrast agents. Gadopentetate dimeglumine may be used as a marker of microcirculatory plasma flow.

Animals↗
PubMed1994

Amplification of the epidermal-growth-factor-receptor gene correlates with different growth behaviour in human glioblastoma.

The objective of our study was to determine the frequency of EGF-receptor-gene rearrangement in relation to tumour-growth behaviour in an unselected group of glioma patients. We investigated 73 glial tumours with different grades of malignancy (17 low-grade gliomas, 14 anaplastic variants, and 42 GBM) by Southern analysis, reverse transcriptase PCR (RT-PCR) amplification of mRNA, and Western analysis. An amplification of the EGF-receptor gene was present in 19/42 GBM but in only 1 anaplastic astrocytoma. By RT-PCR, 4/19 GBM with gene amplification showed a specific amino-terminal aberrant splice mutation of 801 bp in addition to undeleted mRNA. By Western analysis, 27/42 GBM showed expression of the EGF-receptor protein. Protein levels, however, varied among individual tumours. Four GBM containing an aberrant splice mutation exhibited an immunoreactive protein of 130 kDa MW in addition to the normal EGF-receptor protein p170. All GBM patients underwent surgery followed by a standard course of radiotherapy. Neuroradiological follow-up in 31/42 GBM patients consisted of bimonthly MRI examinations. There was a statistically significant difference in the mean latency period until tumour regrowth of patients suffering from GBM with and without EGF-receptor-gene amplification (9 weeks vs. 32 weeks). Our data indicate more rapid tumour regrowth kinetics of GBM with amplified EGF receptor genes in vivo.

Adolescent↗
PubMed1994

MRI monitoring of experimental cerebral ischaemia: comparison of two models.

In experimental stroke research one of the key questions is whether animals models truly reflect human disease. One important reason for modelling stroke is to produce tissue changes that can be used to validate the correlation between the results of advanced radiological imaging and pathology. The aim of this study was to compare two minimally invasive rat models of focal ischaemic stroke as to their ability to simulate clinical stroke reproducibly. In one model a focal infarct was induced using the photochemical Rose Bengal technique. The second model was based on transvascular occlusion of the middle cerebral artery using a cervical approach. In all animals we performed MRI at different times with two different paramagnetic contrast agents. The time course of blood-brain-barrier disruption in the Rose Bengal model differed entirely from that in human brain ischaemia. The experimental stroke showed marked contrast enhancement in the first hour after the onset of ischaemia. On the other hand, the MRI changes in the suture occlusion model were very similar to the changes observed in human brain ischaemia: no early disruption of the blood-brain-barrier and increased T2-signal 4-6 h after the onset of stroke. We hope that the suture occlusion model will be used for research not only by basic and clinical scientists but also by radiologists, who, using modern imaging methods, may greatly influence the diagnosis as well as the management of this devastating disease.

Animals↗
PubMed1994

Significance of haemorrhagic lacunes on MRI in patients with hypertensive cerebrovascular disease and intracerebral haemorrhage.

Our purpose was to determine the frequency and significance of haemorrhagic lacunes (HL) on MRI in patients with a history of, or at risk for intracerebral haemorrhage. We examined 72 patients with old spontaneous intracerebral haemorrhage (ICH) using T1- and T2-weighted spin-echo sequences. MRI studies of 137 consecutive patients with cerebrovascular disease but no known ICH were also reviewed. Both groups showed about the same degree of age-related white matter change and nonhaemorrhagic lacunar infarcts, whereas the ICH group had a higher frequency of HL (12/72 patients) than the non-ICH group (6/131 patients, p < 0.01). These results correlate well with reported pathological findings. We conclude that haemorrhagic lacunes found on MRI studies of patients with cerebrovascular disease may suggest a higher risk of intracerebral haemorrhage.

Adult↗
PubMed1994

MRI in acute cerebral ischaemia: perfusion imaging with superparamagnetic iron oxide in a rat model.

An imaging technique capable of detecting ischaemic cerebral injury at an early stage could improve diagnosis in acute or transient cerebral ischaemia. We compared the ability of superparamagnetically contrast-enhanced MRI and conventional T2-weighted MRI to detect ischaemic injury early after unilateral occlusion of the middle cerebral artery in 12 male Wistar rats. Permanent vessel occlusion was achieved by a transvascular approach, which has the advantage of not requiring a craniectomy. At 45-60 min after the procedure, the animals had conventional T2-weighted MRI before and after administration of a superparamagnetic contrast agent (iron oxide particles). Unenhanced images were normal in all animals. After administration of iron oxide particles, the presumed ischaemic area was clearly visible, as relatively increased signal, in all animals; this high signal area corresponded to the area of ischaemic brain infarction seen on histological studies. Magnetic susceptibility effects of iron particles cause low signal in normally perfused cerebral tissue, whereas tissue with reduced or absent blood flow continues to give relatively high signal. Our results suggest that superparamagnetic iron particles may significantly reduce the interval between an ischaemic insult and the appearance of parenchymal changes on MRI.

Acute Disease↗
PubMed1994

Laser Doppler flowmetry of focal ischaemia and reperfusion in deep brain structures in rats.

Monitoring cerebral blood flow during focal ischaemia and reperfusion with established techniques such as hydrogen clearance and autoradiography is difficult. Laser Doppler flowmetry is a new technique, it allows one to continuously measure blood flow in small tissue samples. The objective of this study was to compare laser Doppler flowmetry with hydrogen clearance using a new single fiber probe to obtain measurements in deep brain structures and then to show the temporal profile of cerebral blood flow during focal ischaemia and after reperfusion. First, the single fiber laser Doppler method was compared with the hydrogen clearance method in ten Wistar rats. Second, focal cerebral ischaemia was induced in fifteen Wistar rats using a model of middle cerebral artery occlusion based on the intravascular insertion of a nylon suture; reperfusion occurred after withdrawal of the suture. The laser Doppler probe was placed in the lateral caudatoputamen, and local cerebral blood flow was measured continuously before and during occlusion as well as after reperfusion. The relative blood flow values obtained by the laser Doppler method and the hydrogen clearance method showed a good correlation (r = 0.76) and a linear relationship. A rapid decrease in laser Doppler flowmetry to 42 +/- 16% of former baseline values was seen with occlusion of the middle cerebral artery; during occlusion cerebral blood flow remained at this level. Reperfusion resulted in a heterogeneous pattern of cerebral blood flow as laser Doppler flowmetry values ranged from 25% to 134% of baseline values. The effects of middle cerebral artery occlusion and reperfusion on cerebral blood flow can be monitored on-line with laser Doppler flowmetry.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Early postoperative magnetic resonance imaging after resection of malignant glioma: objective evaluation of residual tumor and its influence on regrowth and prognosis.

In the vast majority of studies that address the role of surgery in the management of high-grade gliomas, the degree of tumor removal accomplished is solely based on the intraoperative perception of the neurosurgeon. Despite its fundamental importance for a comparison of different treatment modalities, little systematic effort has been made to evaluate the residual gross tumor by neuroimaging methods immediately after surgery. We report the results of a prospective study using contrast-enhanced computed tomography and magnetic resonance imaging (MRI) to monitor 60 patients after the resection of a high-grade glioma. In each case, the first scans were obtained between Days 1 and 5 after surgery, followed by serial imaging every 2 to 3 months, usually until the condition of the patient deteriorated severely or the patient died. Gadolinium-enhanced MRI proved to be extremely valuable for assessing gross residual tumor when performed during Days 1 to 3 after the resection of a preoperatively enhancing high-grade glioma. This timing avoided surgically induced contrast enhancement and minimized interpretative difficulties. In delineating residual tumor, MRI was vastly superior to computed tomography. About 80% of tumor "recurrences" emerged from definitely enhancing remnants, as revealed by early postoperative MRI. The neurosurgeon's estimation of gross tumor burden reduction could be shown to be much less accurate (by a factor of 3) than the postoperative assessment by modern neuroimaging. In our series, residual tumor enhancement was the most predictive prognostic factor of survival in patients with glioblastoma, followed by radiotherapy. Patients with a residual tumor postoperatively had a 6.595-times higher risk of death in comparison to patients without a residual tumor. Patients undergoing radiotherapy had a 0.258-times lower risk of death in comparison to patients who were not treated with radiation. Concerning survival, the prognostic significance of both variables surpassed age and performance.

Brain Neoplasms↗
PubMed1994

[Radiology of cerebrovascular malformations].

Cerebral vascular malformations are, after hypertension, the second most frequent cause of non-traumatic, intracerebral hemorrhage. A reliable intravital diagnosis only became possible with radiological diagnostic methods which also contributed significantly to the development of therapeutic concepts. Diagnostic and therapeutic possibilities for the various forms of cerebral vascular malformations are surveyed in the present review. Since radiology occupies a central position in the diagnosis and (in the meantime also) therapy of cerebral vascular malformations, epidemiological and prognostic factors are also discussed in detail.

Brain Neoplasms↗
PubMed1994

Sensitivity and prognostic value of early CT in occlusion of the middle cerebral artery trunk.

PURPOSE: To investigate the incidence and prognostic value of local brain swelling, the extent of parenchymal hypodensity, and the hyperdense middle cerebral artery sign as shown by CT within the first 5 hours after the onset of symptoms in patients with angiographically proved middle cerebral artery trunk occlusions. METHODS: Fifty-three patients were studied prospectively with CT 46 to 292 minutes (median, 120; mean, 134 +/- 59) after symptom onset and scored clinically at admission and 4 weeks later. All patients were treated with recombinant tissue plasminogen activator (30 to 100 mg). RESULTS: Early CT showed parenchymal hypodensity in 43 patients (81%), local brain swelling in 20 patients (38%), and hyperdensity of the middle cerebral artery trunk in 25 patients (47%). Hypodensity covering more than 50% of the middle cerebral artery territory had an 85%, local brain swelling a 70%, and the hyperdense middle cerebral artery sign a 32% positive predictive value for fatal clinical outcome. Specificity of these findings for fatal outcome was 94%, 83%, and 51%, respectively, and sensitivity was 61%, 78% and 44%, respectively. CONCLUSIONS: Early CT in acute middle cerebral artery trunk occlusion is highly predictive for fatal clinical outcome if there is extended hypodensity or local brain swelling despite aggressive therapeutic attempts such as thrombolysis or decompressive surgery.

Adult↗
PubMed1993

Accelerated methaemoglobin formation: potential pitfall in early postoperative MRI.

Postoperative magnetic resonance imaging (MRI) of glioblastomas to assess residual tumour should be performed within the first 4 days following surgery. Early methaemoglobin formation near the resection site may mimic residual tumour if only gadolinium-DTPA-enhanced images are obtained. In a prospective study 24 of 54 patients (44%) showed well-defined areas of increased signal intensity on unenhanced T1-weighted images performed soon after surgery. By in vitro experiments we showed that hydrogen peroxide used in neurosurgery as a styptic agent accelerates formation of methaemoglobin when added to whole blood samples.

Brain↗
PubMed1993

Clipping of proximal paraclinoid aneurysms with support of the balloon-catheter "trapping-evacuation" technique. Technical note.

A method is described in which we use a combined endovascular balloon-catheter technique and open microneurosurgical approach for clipping aneurysms of the proximal paraclinoidal intracranial segment of the internal carotid artery. By temporary occlusion of the cervical carotid artery and continuously retrograde sucking of blood from the distal vessel via a double-lumen balloon-catheter, clip application to large and critically located aneurysms is facilitated applying evacuation-decompression to the trapped arterial segment under intra-operative SEP-monitoring.

Adult↗
PubMed1993

Prospective evaluation of the prognostic significance of evoked potentials in acute basilar occlusion.

OBJECTIVE: To establish valid prognostic parameters in patients with acute basilar artery occlusive disease. DESIGN: A prospective study. SETTING: Neurocritical care unit at the University of Heidelberg. PATIENTS: Twenty-three patients (12 male, 11 female; 32 to 69 yrs of age, median 54) with acute basilar occlusions. INTERVENTIONS: Angiography, brainstem auditory and somatosensory evoked potentials. MEASUREMENTS AND MAIN RESULTS: Clinical and electrophysiologic data were obtained before angiography and thrombolytic therapy. Outcome was classified according to a slightly modified Glasgow Outcome Scale at discharge from the intensive care unit (ICU). Level of consciousness was determined in four classes: awake (n = 4); somnolence (n = 7); stupor (n = 4); and coma (n = 8). Bilateral recordings of brainstem auditory and somatosensory evoked potentials were ranked in three categories: normal; one side normal; and both sides abnormal. Of 23 sets of evoked potential recordings, brainstem auditory evoked potentials were normal in seven patients, one side abnormal in four patients, and both sides abnormal in 12 patients. Somatosensory evoked potentials were normal in eight patients, one side abnormal in eight patients, and both sides abnormal in seven patients. A combination of both evoked potential modalities demonstrated normal results in three patients, one side abnormal recordings in six patients, and both sides abnormal findings in 14 patients. Outcome was ranked in three groups: five individuals had a good recovery or moderate disability; two patients remained severely disabled; and 16 patients persisted either in a locked-in state or died. Statistical analysis using Fisher's exact test demonstrated a significant correlation between the initial brainstem auditory evoked potential findings and outcome (p < .005), while for the initial somatosensory evoked potentials a significant correlation with outcome was not identified (p = .089). All patients with normal brainstem auditory and somatosensory evoked potential findings did well, whereas all patients with bilateral (both sides) abnormal brainstem auditory evoked potential and bilateral abnormal somatosensory evoked potential remained locked-in or died. CONCLUSION: Initial brainstem auditory evoked potential and somatosensory evoked potential testing are valid prognostic parameters on which to base therapeutic decisions in patients with acute basilar occlusion.

Acute Disease↗
PubMed1993

[Goniotrepanation combined with sinus surgery as a transitional measure in spontaneous carotid artery-cavernous sinus fistulas].

Two patients with spontaneous, angiographically proven fistulas showed progressive ocular symptoms which precluded waiting for spontaneous occlusion of the fistulas. On the other hand, endovascular therapy of the carotid-cavernous fistulas was not possible because the arterial supply of the fistulas came from both internal carotids. Therefore filtering surgery was performed in the affected eyes. Postoperatively, intraocular pressure decreased to normal values in both patients and the symptoms resolved. The visual acuity increased in one patient and remained the same in the other. In conclusion, filtering surgery is an important therapeutic tool to preserve visual function in eyes with carotid-cavernous fistulas that display progressive ocular symptoms but cannot be treated by embolization.

Aged↗
PubMed1993

[Thrombolysis in acute cerebral ischemia].

During the last years some medical centers have performed emergency treatment for intracranial thromboembolic occlusions by thrombolysis using streptokinase, urokinase, and recombinant tissue plasminogen activator intraarterially or intravenously. So far, it appears that the risk of intracranial hemorrhage with clinical deterioration is not increased by thrombolysis if thrombolysis is performed during the first 8 hours after symptom onset. Successful recanalization of occlusions in the anterior or posterior circulation is associated with a decrease of mortality and morbidity. Intraarterial application of the thrombolytic agent seems to be more effective than intravenous application. However, there is still a lack of controlled studies that could exclusively prove which thrombolytic agent and which mode of application is the most effective with regard to arterial recanalization and clinical outcome.

Acute Disease↗
PubMed1993

[Radiology of stroke].

Today radiologic methods play an important role in the diagnosis of cerebral stroke. The aim of the radiologist, however, should not only be to classify the stroke into the four main categories (ischemic stroke, intracerebral bleeding, subarachnoid hemorrhage, sinovenous thrombosis), but also to interpret the findings with regard to the etiology of the disease. The pattern of lesions gives information about the etiology of ischemic stroke; the correct interpretation of these lesion patterns allows one to optimize therapeutic decisions. This paper additionally focuses on the differential diagnosis of intracerebral hemorrhage and the CT and MR signs of sinovenous thrombosis. New developed concepts in the field of stroke therapy and prophylaxis call for authority and continuous education of the radiologist on this topic. Pure descriptions of radiologic findings without an understanding of the pathogenesis of the disease will be ignored by the clinician. On the other hand, the radiologist can turn the therapeutic decisions in the right direction by combining morphological descriptions with pathogenetic orientated interpretations. In this way, the radiologist can contribute to the reduction of costs in the public health system.

Cerebrovascular Disorders↗