Biomedical subjects

G Schroth

Publications and source records attributed to G Schroth.

At least 19 recordsLinked to original sources

PubMed2006

Reasons to withhold intra-arterial thrombolysis in clinical practice.

BACKGROUND: In selected stroke centers intra-arterial thrombolysis (IAT) is used for the treatment of acute stroke patients presenting within 6 hours of symptom onset. However, data about eligibility of acute stroke patients for IAT in clinical practice are very scarce. METHODS: We collected prospectively data on indications advising for or against IAT of 230 consecutive stroke patients in a tertiary stroke center. RESULTS: 76 patients (33.0%) presented within 3 hours, 69 (30%) between 3 and 6 hours of symptom onset and 85 (37%) later than 6 hours. Arteriography was performed in 71 patients (31%) and IAT in 46 (20%). In 11 patients no or only peripheral branch occlusions were seen on arteriography and therefore IAT was not performed. In 9 patients the ICA was occluded and barred IAT and in five anatomical or technical difficulties made IAT impossible. 72 patients presenting within 6 hours did not undergo arteriography and thrombolysis, mostly because of mild (n=44) or rapidly improving neurological deficits (n=13). Other reasons to withhold IAT were CT and/or clinical findings suggesting lacunar stroke due to small vessel occlusion (n=7), limiting comorbidty (n=7) and baseline international normalized ratio>1.7 (n=1). CONCLUSIONS: A third of the patients underwent diagnostic arteriography and one fifth received IAT. The most important reasons to withhold thrombolysis were presentation beyond the 6 hours time window and mild or rapidly improving symptoms.

Adolescent↗

PubMed2006

Impact of comorbidity on ischemic stroke outcome.

OBJECTIVE: To evaluate the impact of comorbidity on stroke outcome of patients admitted to a general ward (GW) and a stroke unit (SU). METHODS: Data of 266 patients with acute ischemic stroke (GW: 103, SU: 163) were collected prospectively for 13 months. Clinical and radiological findings, and the Charlson Comorbidity Index (CCI) were recorded. Predictors of outcome 4 months after stroke were analyzed. Favorable outcome was defined as modified Rankin Scale (mRS) score of < or = 2, unfavorable as mRS >2. RESULTS: The mean age of the patients was 67.2 years (SD = 14.4), the mean CCI 1.2 (SD = 1.4). In univariate analysis, small artery disease predicted favorable outcome (P < 0.001) and age (P = 0.022), high National Institutes of Health Stroke Scale (NIHSS) score (P < 0.001), high CCI (P < 0.001), treatment in a GW (P = 0.004), coronary artery disease (P = 0.02), dementia (P = 0.009), diabetes (P = 0.005) and atrial fibrillation (P < 0.001) unfavorable outcome after 4 months. In multivariate analysis, high NIHSS score (P < 0.001), atrial fibrillation (P = 0.004), coronary artery disease (P = 0.012) and diabetes (P = 0.031) were predictors of unfavorable outcome. CONCLUSIONS: Comorbidity has a significant impact on stroke outcome. In addition to stroke severity, atrial fibrillation, coronary artery disease and diabetes were predictors of outcome after stroke, but not the sum of the CCI.

Adult↗

PubMed2006

Early assessment of brain maturation by MR imaging segmentation in neonates and premature infants.

PURPOSE: We evaluated the impact of premature extrauterine life on brain maturation. PATIENTS AND METHODS: Twelve neonates underwent MR imaging at 40 (39.64 +/- 0.98) weeks (full term). Fifteen premature infants underwent 2 MR imaging examinations, after birth (preterm at birth) and at 40 weeks (41.03 +/- 1.33) (preterm at term). A 3D MR imaging technique was used to measure brain volumes compared with intracranial volume: total brain volume, cortical gray matter, myelinated white matter, unmyelinated white matter, basal ganglia (BG), and CSF. RESULTS: The average absolute volume of intracranial volume (269.8 mL +/- 36.5), total brain volume (246.5 +/- 32.3), cortical gray matter (85.53 mL +/- 22.23), unmyelinated white matter (142.4 mL +/-14.98), and myelinated white matter (6.099 mL +/-1.82) for preterm at birth was significantly lower compared with that for the preterm at term: the average global volume of intracranial volume (431.7 +/- 69.98), total brain volume (391 +/- 66,1), cortical gray matter (179 mL +/- 41.54), unmyelinated white matter (185.3 mL +/- 30.8), and myelinated white matter (10.66 mL +/- 3.05). It was also lower compared with that of full-term infants: intracranial volume (427.4 mL +/- 53.84), total brain volume (394 +/- 49.22), cortical gray matter (181.4 +/- 29.27), unmyelinated white matter (183.4 +/- 27.37), and myelinated white matter (10.72 +/- 4.63). The relative volume of cortical gray matter (30.62 +/- 5.13) and of unmyelinated white matter (53.15 +/- 4.8) for preterm at birth was significantly different compared with the relative volume of cortical gray matter (41.05 +/- 5.44) and of unmyelinated white matter (43.22 +/- 5.11) for the preterm at term. Premature infants had similar brain tissue volumes at 40 weeks to full-term infants. CONCLUSION: MR segmentation techniques demonstrate that cortical neonatal maturation in moderately premature infants at term and term-born infants was similar.

Brain↗

PubMed2005

Degeneration of the cervical disc: histology compared with radiography and magnetic resonance imaging.

Decisions about the treatment of neck pain are largely made on the basis of information gained from plain X-rays and magnetic resonance imaging (MRI), which are used routinely as part of preliminary investigation. We performed a descriptive cadaveric study to compare histology with radiography and MRI. We correlated plain radiography, disc height [Farfan index (FI)] and MRI findings with histology to assess the ability of radiology to detect significant pathologic lesions. The study included 52 motion segments from nine subjects over the age of 50, who underwent routine hospital autopsy. Disc degeneration was assessed by histology, radiography, disc height (FI: anterior disc height plus posterior disc height divided by anterioposterior diameter) and MRI using established grading systems. Most of the discs were classified radiologically as grade 1 (19/52), grade 2 (13/52), grade 3 (9/52) or grade 4 (3/52). Eight of the discs were graded as normal. The distribution of MRI grades was grade 0 (9/36), grade 1 (9/36), grade 2 (7/36), grade 3 (8/36) and grade 4 (3/36). Half of the discs (26/52) showed advanced (grade 4) degeneration histologically. FI correlated with histological grade (P = 0.013), MRI grade (P = 0.02) and radiological grade (P < 0.001) of degeneration. Radiological and histological grade of degeneration showed a weak correlation (r = 0.3, P = 0.033). MRI correlated with overall histological grade (r = 0.41, P = 0.015, n = 34). Histological features (e.g., tears, rim lesions, prolapse of nucleus material) were poorly recognised by MRI, which had a sensitivity for disc material prolapse and annulus tears of less than 40%. Our study showed that discs from patients over 50 years are histologically severely degenerated; however, these changes may not be detected by conventional radiography and MRI.

Aged↗

PubMed2005

Comparison of intra-arterial thrombolysis with conventional treatment in patients with acute central retinal artery occlusion.

BACKGROUND: Several case series and a recent meta-analysis indicate that intra-arterial thrombolysis (IAT) is effective for the treatment of acute central retinal artery occlusion (CRAO). METHODS: A total of 37 patients with acute monocular blindness because of unilateral thromboembolic CRAO were treated with IAT using urokinase within six hours of the onset of symptoms. Visual outcome was compared with a control group of 19 patients, also seen within six hours, who did not undergo thrombolytic treatment. In both groups some patients were treated by paracentesis and/or acetazolamide. Predictors of visual outcome were evaluated. RESULTS: Visual improvement was more likely with IAT (p = 0.01) as were the chances to regain visual acuity of >0.6 significantly better (p = 0.04): 8/37 patients (22%) regained visual acuity of >0.6 in the IAT group and none (0/19) in the control group. Younger patients were more likely to regain some vision with (p = 0.012) or without IAT (p = 0.026). Three patients had minor treatment related cerebral ischaemic events, two had transient ischaemic attacks and one a minor stroke. There were no haemorrhagic complications. CONCLUSIONS: This series of patients with CRAO demonstrated that IAT enhanced the chances of visual improvement compared with conventional treatment only. Furthermore, younger patients have a better chance to achieve some visual recovery.

Acute Disease↗

PubMed2005

Ischaemic stroke in young adults: predictors of outcome and recurrence.

BACKGROUND: There is limited information about predictors of outcome and recurrence of ischaemic stroke affecting young adults. OBJECTIVE: To assess the predictive value of the presenting characteristics for both outcome and recurrence in young stroke victims. METHODS: Clinical and radiological data for 203 patients aged 16 to 45 years were collected prospectively; they comprised 11% of 1809 consecutive patients with ischaemic stroke. The National Institutes of Health stroke scale (NIHSS), the Bamford criteria, and the trial of ORG 10172 in acute stroke treatment (TOAST) classification were used to define stroke severity, subtype, and aetiology. The clinical outcome of 198 patients (98%) was assessed using the modified Rankin scale (mRS) and categorised as favourable (score 0-1) or unfavourable (score 2-6). RESULTS: Stroke was caused by atherosclerotic large artery disease in 4%, cardioembolism in 24%, small vessel disease in 9%, another determined aetiology in 30%, and undetermined aetiology in 33%. Clinical outcome at three months was favourable in 68%, unfavourable in 29%, and lethal in 3%. Thirteen non-fatal stroke, two fatal strokes, and six transient ischaemic attacks (TIA) occurred during a mean (SD) follow up of 26 (17) months. High NIHSS score, total anterior circulation stroke, and diabetes mellitus were independent predictors of unfavourable outcome or death (p<0.0001, p = 0.011, and p = 0.023). History of TIA predicted stroke recurrence (p = 0.02). CONCLUSIONS: Severe neurological deficits at presentation, total anterior circulation stroke, and diabetes mellitus predict unfavourable outcome. Previous TIA are associated with increased risk of recurrence.

Adolescent↗

PubMed2005

Recanalisation of middle cerebral artery occlusion after intra-arterial thrombolysis: different recanalisation grading systems and clinical functional outcome.

BACKGROUND: Different grading systems of arterial recanalisation have never been compared in large series of stroke patients treated with intra-arterial thrombolysis (IAT). METHODS: Clinical and angiographic findings and outcome were analysed in 147 patients with M1 or M2 segment occlusion of the middle cerebral artery treated with IAT. Associations of the thrombolysis in myocardial infarction (TIMI) grading system and the Mori grading system with clinical outcome were compared. RESULTS: The median NIHSS score on admission was 15 and the mean time from symptom onset to IAT was 242 minutes. After three months the outcome was favourable (defined as modified Rankin scale score (mRS) < or = 2) in 85 patients (58%) and poor (mRS 3 to 5) in 44 (30%); 18 patients (12%) were dead. Recanalisation was categorised as TIMI grade 0 in 17 patients (12%), TIMI 1 in 16 (11%), TIMI 2 in 83 (56%), and TIMI 3 in 31(21%). Seventeen patients (12%) showed Mori grade 0 reperfusion, 16 (11%) Mori 1, 37 (25%) Mori 2, 46 (31%) Mori 3, and 31 (21%) Mori 4. In both TIMI and Mori grading systems, reopening the artery was an independent predictor of a favourable clinical outcome (p < 0.0001). When recanalisation was partial, outcome was better in patients with reperfusion >50% (Mori 3) than in those with reperfusion <50% (Mori 2) (p = 0.008). CONCLUSIONS: Both TIMI and Mori grading systems are useful for predicting outcome after stroke and IAT. When recanalisation is partial the Mori classification is more refined in giving prognostic information.

Adolescent↗

PubMed2004

Locally induced hypothermia for treatment of acute ischaemic stroke: a physical feasibility study.

During the treatment of stroke by local intra-arterial thrombolysis (LIT) it is frequently possible to pass the blood clot with a micro-catheter, allowing perfusion of brain tissue distally to the occlusion. This possibility allows for new early treatments of ischaemic brain tissue, even before the blood clot has been removed. One potential new approach to preserve brain tissue at risk may be locally induced endovascular hypothermia. Physical parameters such as the required micro-catheter input pressure, output velocity and flow rates, and a heat exchange model, applicable in the case of a micro-catheter placed within a guiding catheter, are presented. Also, a simple cerebral temperature model is derived that models the temperature response of the brain to the perfusion with coolant fluids. Based on this model, an expression has been derived for the time needed to reach a certain cerebral target temperature. Experimental in vitro measurements are presented that confirm the usability of standard commercially available micro-catheters to induce local hypothermia of the brain. If applied in vivo, the model predicts a local cooling rate of ischaemic brain tissue of 300 g of approximately 1 degrees C in 1 min, which is up to a factor 30-times faster than the time-consuming systemic hypothermia via the skin. Systemic body temperature is only minimally affected by application of local hypothermia, thus avoiding many limitations and complications known in systemic hypothermia.

Algorithms↗

PubMed2004

Acute stenting and thromboaspiration in basilar artery occlusions due to embolism from the dominating vertebral artery.

Intra-arterial thrombolysis (IAT) is the only treatment that has demonstrated benefit in patients with acute basilar artery occlusions (ABAO). IAT may be difficult to perform when access to the occluded basilar artery (BA) is prevented by pathology of the vertebral arteries (VA). We report on two patients with ABAO due to embolism from the dominating VA. Catheter navigation through the occluded VA and thromboaspiration enabled access to the BA. Thromboaspiration alone or in addition to IAT resulted in a complete recanalization of the BA and a favorable clinical outcome. A stent was deployed at the site of the stenosis in the VA either prior to or immediately after BA recanalization.

Adult↗

PubMed2004

Diffusion-weighted MRI in cortical ischaemia.

We carried out MRI on 16 male and three female comatose patients, aged 2 days to 79 years, with suspected cortical ischaemia referred from our intensive care units. Using a head coil, and following standard imaging, including coronal fluid-attenuated inversion-recovery images, we performed diffusion-weighted imaging (DWI) using a whole-brain multislice single-shot echo-planar sequence with b 0 and 1000 s/mm2: 5-mm slices covering the whole brain, TR 7000 TE 106 ms, 128 x 128 pixels, field of view 250 mm, one excitation. Maps of apparent diffusion coefficients (ADC) were generated automatically. DWI showed cortical, basal ganglia and watershed-area high signal in all cases, associated with a decrease in ADC to 60- 80% of normal. DWI showed lesions not seen (40%) or underestimated (40%) on conventional T2-weighted imaging. Within 24 h of the onset of symptoms, DWI showed changes not readily detectable on T2-weighted images. The cortical high signal on DWI and the ADC changes, suggesting severe ischaemia rather than oedema, was found in areas known to be affected by cortical laminar necrosis. Extension to the brain stem and white matter was associated with a higher likelihood of death.

Adolescent↗

PubMed2004

Clinical and radiological predictors of recanalisation and outcome of 40 patients with acute basilar artery occlusion treated with intra-arterial thrombolysis.

OBJECTIVE: To define predictors of recanalisation and clinical outcome of patients with acute basilar artery occlusions treated with local intra-arterial thrombolysis (IAT). METHODS: Vascular risk factors, severity of the neurological deficit graded by the National Institutes of Health stroke scale (NIHSS), and radiological findings were recorded at presentation. Outcome was measured using the modified Rankin scale (mRS) three months later and categorised as favourable (mRS 0-2), poor (mRS 3-5), or death (mRS 6). RESULTS: 40 patients were studied. Median NIHSS on admission was 18. Mean time from symptom onset to treatment was 5.5 hours (range 2.3 to 11). Outcome was favourable in 14 patients (35%) and poor in nine (23%); 17 (42%) died. There were two symptomatic cerebral haemorrhages (5%). Recanalisation of the basilar artery was achieved in 32 patients (80%); it was complete (TIMI grade 3) in 20% and partial (TIMI grade 2) in 60%. In multivariate logistic regression analysis, low NIHSS score on admission (p = 0.002) and vessel recanalisation (p = 0.005) were independent predictors of favourable outcome. Recanalisation occurred more often with treatment within six hours of symptom onset (p = 0.003) and when admission computed tomography showed a hyperdense basilar artery sign (p = 0.007). In a univariate model, quadriplegia (p = 0.002) and coma (p = 0.004) were associated with a poor outcome or death. CONCLUSIONS: Low baseline NIHSS on admission and recanalisation of basilar artery occlusions predict a favourable outcome after intra-arterial thrombolysis. Early initiation of IAT and the presence of a hyperdense basilar artery sign on CT were associated with a higher likelihood of recanalisation.

Acute Disease↗

PubMed2003

Multiresolution fuzzy clustering of functional MRI data.

Recent developments in the analysis of functional MRI data reveal a shift from hypothesis-driven statistical tests to unsupervised strategies. One of the most promising approaches is the fuzzy clustering algorithm (FCA), whose potential to detect activation patterns has already been demonstrated. But the FCA suffers from three drawbacks: first the computational complexity, second the higher sensitivity to noise and third the dependence on the random initialization. With the multiresolution approach presented here, these weak points are significantly improved, as is demonstrated in our tests with simulated and real functional MRI data.

Algorithms↗

PubMed2003

Diffusion-weighted MRI in acute spinal cord ischaemia.

Acute spinal cord ischaemia is often undetectable with conventional MRI. Diffusion-weighted MRI (DWI) has been difficult to use in the spine because of susceptibility artefacts. We assessed the diagnostic value of echoplanar DWI for early confirmation of spinal cord ischaemia. We performed conventional MRI and DWI in two men and three women, aged 54-75 years with clinically suspected acute spinal cord ischaemia. Imaging was performed 9-46 h after the onset of symptoms, and 2-9 days later to assess the extent of ischaemic signal change. Spatial resolution of DWI within the spine using standard equipment was poor, but in all patients, early DWI revealed areas of high signal indicating decreased diffusion, confirmed by measurement of apparent diffusion coefficients. Follow-up MRI showed high signal on T2-weighted images and contrast enhancement at the expected levels. Neurological deficits corresponded with radiological findings in four patients: various syndromes, including isolated bilateral weakness or sensory change and combined deficits, were found. Echoplanar DWI may be helpful for confirmation of spinal cord ischaemia in the acute stage, but follow-up T2-weighted images have superior spatial resolution and correlation with clinical findings and lesion extent.

Acute Disease↗

PubMed2003

Isotropic apparent diffusion coefficient mapping of postnatal cerebral development.

Diffusion-weighted imaging (DWI) allows us to image the motion of tissue water. This has been used to demonstrate acute ischaemia. Diffusion imaging is also sensitive to water movement along neuronal tracts. Our objective was to map brain maturation in vivo using maps of apparent diffusion coefficient (ADC). We studied 22 children without neurological disease aged between 2 and 720 days. MRI was performed at 1.5 tesla. Multislice single-shot echoplanar DWI was performed at b 0 and 1000 s/mm(2). ADC maps were generated automatically and measurements were performed in the basal ganglia, frontal and temporal white matter and the pons. There was a decrease over time in water diffusion in the areas examined, most marked in the frontal (0.887-1.898 x 10(-3) mm(2)/s) and temporal (1.077-1.748 x 10(-3) mm(2)/s)lobes. There was little change, after an initial decrease, in the basal ganglia (0.690-1.336 x 10(-3) mm(2)/s). There was a difference in water diffusion between the anterior (0.687-1.581 x 10(-3) mm(2)/s) and posterior (0.533-1.393 x 10(-3) mm(2)/s) pons. These changes correlate well with those observed in progressive myelination: the increased water content probably reflects incomplete myelination and the decrease with time in water motion reflects the increase in myelinated brain.

Brain Mapping↗

PubMed2003

Changes on diffusion-weighted MRI with focal motor status epilepticus: case report.

Transient imaging abnormalities, including changes on diffusion-weighted imaging (DWI), may be seen in focal status epilepticus. The changes on DWI provide am insight into the pathophysiology. We report a 53-year-old man with focal motor status epilepticus involving the left hand, arm and face with focal slowing on EEG. The apparent diffusion coefficients (ADC) were higher in the affected hemisphere than on the other side. At 10 days and 6 weeks after the end of the seizures, we saw normal ADCs and atrophy of the affected hemisphere. We conclude that the MRI findings indicate both cytotoxic and vasogenic oedema during seizure activity and subsequent loss of brain parenchyma.

Arm↗

PubMed2003

The dilemma of success: percutaneous coronary interventions in patients > or = 75 years of age-successful but associated with higher vascular complications and cardiac mortality.

Elderly patients are increasingly referred to percutaneous coronary interventions (PCIs). Recent reports suggest complications rates are declining in the elderly. We sought to determine whether procedural and in-hospital outcomes are different in patients aged > or = 75 years undergoing nonemergent PCI as compared to patients age < 75 years. The outcome of 266 consecutive patients age > or = 75 years undergoing nonemergent PCI was compared to that of 1,681 consecutive patients age < 75 years. Compared with younger patients, greater proportions of elderly patients were women and had a history of hypertension, peripheral vascular disease, and cerebral vascular events. Elderly patients had more extensive coronary involvement. Procedural success was similar in both groups (94%). The in-hospital cardiac death rate was significantly higher in the elderly patients (2.3% vs. 0.7%; P = 0.03). Aged patients also had a significantly higher incidence of vascular and bleeding complications. Blood transfusion was required more often in the elderly group (4.5% vs. 2.6%; P = 0.07). The hospitalization length was significantly higher in the elderly group (4.1 +/- 6.0 vs. 2.5 +/- 4.3 day; P = 0.0004). By multivariate logistic regression (adjusted for baseline clinical and angiographic variables), age > or = 75 years was found to be an independent predictor of in-hospital cardiac death (odds ratio = 3.9; 95% CI = 1.3-11.5; P = 0.015). Although PCI is technically successful in patients aged > or = 75 years; it is associated with more acute cardiac and vascular complications and higher in-hospital cardiac mortality.

Age Factors↗

PubMed2003

[Stents in the treatment of supraaortic vessel stenosis].

We describe and discuss our experience of more than 500 endovascular procedures for revascularisation of acute or chronic occlusion and stenosis of supraaortic vessels using stents in 171 cases. Whereas endovascular treatment of the innominate, subclavian and vertebral arteries are routinely used in atherosclerotic occlusive lesions, carotid stenting is currently being investigated as an alternative treatment to carotid endarterectomy and seems to offer a less invasive, less traumatic and less cost expensive alternative to achieve the goal to prevent stroke. In a subgroup of high surgical risk patients carotid artery stenting with simultaneous embolic protection of the cerebral blood flow by filter systems was even superior to the endarterectomy-treated patients in a prospective, randomized multi-center study (SAPPHIRE): at 30-day follow up the major event rate for the stented group of 156 patients was 5.8% versus 12.6 for the 151 endarterectomy-treated patients.

Angiography↗

PubMed2003

[Therapeutic interventional neuroradiology in acute stroke].

Interventional neuroradiological techniques are described, which are used for revascularisation of the intra-extracranial vessels in acute stroke. The results are based on our experience gained during the endovascular treatment of more than 300 patients suffering from acute stroke during the last years. Indication, procedures and results of intraarterial thrombolysis, thrombo-aspiration, percutaneous transluminal angioplasty, and implantation of stents in cases of occlusion or pseudoocclusion of brain supplying vessels are discussed. Furthermore first experiences with new techniques from other centers are presented, e.g., thrombolysis by ultrasound (sonothrombolysis), by angiojet aspiration, and laser evaporation of the thromboembolic occlusion of intra- and extracranial blood vessels.

Acute Disease↗