Biomedical subjects

S Vorstrup

Publications and source records attributed to S Vorstrup.

75 records · Page 5Linked to original sources

PubMedDate not supplied

CBF before and after extracranial-intracranial bypass surgery in patients with ischemic cerebrovascular disease studied with 133Xe-inhalation tomography.

Cerebral blood flow (CBF) was studied by 133Xenon inhalation tomography in 22 patients with symptoms of ischemic cerebrovascular disease before and after establishment of an extracranial-intracranial bypass shunt. Selection of patients for shunting was based on angiographically demonstrated arterial occlusions and on the finding of focal low flow areas corresponding to the clinical symptoms, that consisted mainly of minor stroke with good remission and with or without subsequent TIAs. It was required that the area of low flow should clearly exceed the CT lesion present in practically all cases. Following surgery, the permanent neurologic deficits remained unchanged, while the TIAs stopped in all but one case. Two patients showed a definite increase of CBF in the low flow area while another two showed a questionable increase. All the other cases, 18 of the 22, showed an unchanged tomographic flow map with no trend towards diminution in extension or severity of the focal hypoperfused area. A persistent low flow in areas with no corresponding CT lesion following alleviation of a possible flow impediment is interpreted to represent an incomplete infarction or diaschisis.

Adult↗

PubMedDate not supplied

Cell density in the border zone around old small human brain infarcts.

Nine brain autopsy cases of small old cerebral infarcts were selected for neuropathological studies. Eight of the patients had cortical infarcts, in two cases with extension into the striate body. In one case the infarct involved the striate body only. The density of neurons and glial cells was measured in the coronal and the horizontal planes at various distances from the margin of the infarct. Corresponding counting points in the contralateral hemisphere served as control. On light microscopy, the infarcted cortex was irregularly shaped, but on serial sections the bulging parts appeared to be cut off from the infarcted tissue ("pseudo-infarct islands"). The zone of transition from infarcted to normal brain tissue was less than a few mm wide. In one patient, tomographic measurements of the cerebral blood flow (CBF) and a CT scan could be compared with the neuropathological findings. In this patient, CBF in the surroundings of the infarct was decreased despite a normal neuronal density. The study supports the traditional view held by pathologists that a sharp transition exists between infarcted and normal brain tissue and suggests that the hypoperfusion zone surrounding the region of complete infarction may be due to mechanisms other than selective loss of neurons.

Brain↗

PubMedDate not supplied

Evaluation of the cerebral vasodilatory capacity by the acetazolamide test before EC-IC bypass surgery in patients with occlusion of the internal carotid artery.

Cerebral blood flow (CBF) was measured by xenon-133 inhalation tomography in 18 patients with cerebrovascular disease before and 4 months after extracranial-intracranial bypass surgery. Only patients who showed a reduced CBF in areas that were intact on the CT scan and relevant to the clinical and angiographical findings were operated. The majority of the patients had suffered a minor stroke with or without subsequent transient ischemic attacks. They were studied at least 6 weeks following the stroke. All patients had an occlusion of the relevant internal carotid artery. To identify preoperatively the patients with a compromised collateral circulation and hence reduced CBF due to reduced perfusion pressure, a cerebral vasodilatory stress test was performed using acetazolamide (Diamox). In normal subjects, Diamox has been shown to increase tomographic CBF without change of the flow distribution. In the present series 9 patients showed a significant redistribution of flow in favor of the non-occluded side ("positive" Diamox test). Two of these 9 patients showed even a paradoxical decrease in focal CBF preoperatively, i.e., a "steal" effect. These 2 patients were the only patients who improved in focal CBF after shunting. The remaining 9 patients all showed uniform flow responses ("negative" Diamox test), and none of these increased in focal CBF postoperatively. The finding of an unchanged flow map postoperatively confirmed that the low flow areas were not due to restricted flow via collateral pathways. However, an increase in the regional vasodilatory capacity was observed postoperatively in the majority of patients.

Acetazolamide↗