Bernhard Widder

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BACKGROUND AND PURPOSE Retrospective studies have found a close correlation between an impaired cerebrovascular reserve capacity and the incidence of hemodynamic stroke. The present study evaluates this relation prospectively. METHODS We measured the CO2 reactivity in 85 patients with internal carotid artery occlusions by transcranial Doppler sonography(More)
Since 1986, German ultrasound criteria for grading carotid stenosis have followed the local diameter reduction percentage consistent with the definition used in the European Carotid Surgery Trial (ECST) definition. To overcome the confusion caused by the coexisting grading method used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET),(More)
BACKGROUND AND PURPOSE Assessing both stroke patients and their CT scans by using a conventional videoconference system offers an interesting opportunity to improve stroke care in rural areas. However, until now there have been no studies to suggest whether this method is feasible in routine stroke management. METHODS Seven rural hospitals in the southern(More)
BACKGROUND AND PURPOSE Patients with internal carotid artery occlusions and highly impaired cerebrovascular reactivity have been identified as having an increased risk of stroke. It is still unclear, however, whether cerebral hemodynamics may be restored in the course of time by the development of collaterals. METHODS During a 5-year period we assessed(More)
Cerebral CO2-reactivity was tested by transcranial Doppler sonography (Doppler CO2 test) in 232 patients. Time averaged flow velocity in the middle cerebral artery at the 40 mm Hg blood PCO2 level was taken as a reference point, and the relative increase of flow in hypercapnia of 46.5 mm Hg pCO2 was defined as “Normalized Autoregulatory Response” (NAR). A(More)
BACKGROUND AND PURPOSE Lesions in the centrum ovale may be classified as microangiopathic (lacunar) lesions and hemodynamic infarctions. To distinguish between them, a size of more than 2 cm has been postulated for hemodynamic infarctions. The reliability of this criterion was assessed with MR imaging. METHODS In 16 patients with unilateral or bilateral(More)
  • B Widder
  • Journal of neurology, neurosurgery, and…
  • 1989
In patients with an internal carotid artery (ICA) occlusion who suffer from ipsilateral transient ischaemic attacks or minor stroke extra/intracranial (EC/IC) bypass surgery may be useful only where there is insufficient collateral supply. The transcranial Doppler CO2 test offers a simple method of investigating the residual autoregulatory capacity which(More)
In patients with an internal carotid artery (ICA) occlusion the CO2 reactivity (autoregulatory reserve) is supposed to give information about the function of the collateral supply. To prove this hypothesis we compared the CO2 reactivity measured by transcranial Doppler sonography to the ipsilateral clinical symptoms and the patterns of infarction in cranial(More)
During a 9-month period the carotid arteries of 2420 consecutive patients were investigated by conventional Doppler and duplex ultrasonography as well as by colour-coded duplex sonography. Of 186 internal carotid arteries showing a diameter reduction at the bifurcation level of 95% or more by conventional techniques, 131 underwent X-ray angiography which(More)