FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W3009688322> ?p ?o ?g. }

• W3009688322 abstract "Previous studies have shown an extensive area of ischaemia around an acute intracerebral haematoma, and that this ischaemia contributes to patients' clinical condition and outcome. The relative contribution of tissue pressure and chemical vasoconstriction in the production of ischaemia is uncertain. If vasoconstrictors present in blood were found to play a significant role, and if ischaemia could be detected early, it might prove possible to improve blood flow by pharmacological manipulation of the vasoconstrictor effect. The studies reported here used the new technique of Magnetic Resonance Imaging (MRI) to investigate intracerebral and subarachnoid haemorrhage, and associated changes in the brain parenchyma. Ischaemic change was assayed in an experimental animal model using different intracerebral space-occupying lesions, and local effects of a haematoma were observed at stages up to three months. The first part of the study was concerned with assessing the sensitivity and specificity of MRI in acute and subacute intracranial haemorrhage (ICH). The diagnostic yield of MRI is determined by the choice of radiofrequency (RF) pulse sequences appropriate to the condition. A system was developed which used computer analysis of in vitro relaxation time measurements of brain, blood and cerebrospinal fluid (CSF) to predict optimum pulse sequences for imaging patients with ICH. T1 and T2 of fresh human post-mortem grey matter and white matter, and of CSF from patients undergoing myelography, were measured in vitro using a MR spectrometer. Relaxation times of blood from volunteers, and of CSF samples after the addition of blood to simulate different degrees of subarachnoid haemorrhage (SAH), were also measured daily for 15 days. T1 and T2 of blood fell sharply over the first 48 hours and gradually over the rest of the period. There was an insignificant fall in the values for bloodstained CSF. On day one, there were substantial differences between the relaxation times of all the tissues, but the fall in the relaxation times of blood led to overlap with the values for brain tissue. A simple computer program used these measurements to calculate values for image signal intensity for all the tissues. Signal intensity values were obtained for all the pulse sequence combinations available on the Picker 0.15T imager. From these results, sequences were chosen which produced the greatest separation of the signal intensities, and hence the image contrast, of normal and haemorrhagic tissues. A Spin-echo (SE) 2200/80 sequence was chosen for clinical imaging studies as it combined good tissue contrast with good definition and a short imaging time (9.2 mins). Clinical studies were then undertaken on patients with subarachnoid haemorrhage, intracerebral haematoma and head injury. Conclusions 1. Intracranial haemorrhage from a variety of causes was well demonstrated by Magnetic Resonance Imaging in both acute and subacute situations in three series of selected patients. To diagnose haemorrhage conclusively, care must be exercised in the selection of radiofrequency pulse sequences. Computer modelling of MRI using data from in vitro tissue studies proved to be a useful method of selecting appropriate sequences. 2. MRI showed extensive tissue change around small and large haematomas at an early stage, while the signal intensity of haematomas seen on MR images was lower compared to that of uninvolved brain than had been predicted by in vitro studies. It was thought possible that these two findings might be in part explained by early transudation of fluid from the haematoma, but it was not possible to prove this in patients or to produce an appropriate animal model for MR and tissue analysis. 3. Small animal studies showed an immediate and profound effect on the vasculature in the region of an intracerebral haematoma and at more distant sites which could not be explained solely by its space- occupying effect, as similar-sized lesions of inert fluids did not cause changes of equal extent. It is therefore possible that substances diffusing or tracking from the clot might contribute to ischaemia, but this could not be proven experimentally, although blood was seen to track along the perivascular spaces for some distance from the clot. In the experimental situation widespread ischaemia was transient; local ischaemic change increased to a peak by 48 hours, and reduced progressively thereafter with concomitant phagocytosis and absorption of the clot to leave a small glial scar. (Abstract shortened by ProQuest.)." @default.
• W3009688322 created "2020-03-13" @default.
• W3009688322 creator A5066572610 @default.
• W3009688322 date "1989-01-01" @default.
• W3009688322 modified "2023-09-24" @default.
• W3009688322 title "Acute intracranial haemorrhage : pathophysiological and magnetic resonance studies" @default.
• W3009688322 cites W1991094324 @default.
• W3009688322 cites W1996355804 @default.
• W3009688322 cites W2007349861 @default.
• W3009688322 cites W2010212590 @default.
• W3009688322 cites W2020623316 @default.
• W3009688322 cites W2028386075 @default.
• W3009688322 cites W2058662153 @default.
• W3009688322 cites W2076973948 @default.
• W3009688322 cites W2086807063 @default.
• W3009688322 cites W2095821122 @default.
• W3009688322 cites W2138493909 @default.
• W3009688322 hasPublicationYear "1989" @default.
• W3009688322 type Work @default.
• W3009688322 sameAs 3009688322 @default.
• W3009688322 citedByCount "0" @default.
• W3009688322 crossrefType "dissertation" @default.
• W3009688322 hasAuthorship W3009688322A5066572610 @default.
• W3009688322 hasConcept C10162356 @default.
• W3009688322 hasConcept C126322002 @default.
• W3009688322 hasConcept C126838900 @default.
• W3009688322 hasConcept C142724271 @default.
• W3009688322 hasConcept C143409427 @default.
• W3009688322 hasConcept C157767197 @default.
• W3009688322 hasConcept C158846371 @default.
• W3009688322 hasConcept C2778013878 @default.
• W3009688322 hasConcept C2779651940 @default.
• W3009688322 hasConcept C2780813603 @default.
• W3009688322 hasConcept C2781192897 @default.
• W3009688322 hasConcept C2909286980 @default.
• W3009688322 hasConcept C42219234 @default.
• W3009688322 hasConcept C541997718 @default.
• W3009688322 hasConcept C71924100 @default.
• W3009688322 hasConceptScore W3009688322C10162356 @default.
• W3009688322 hasConceptScore W3009688322C126322002 @default.
• W3009688322 hasConceptScore W3009688322C126838900 @default.
• W3009688322 hasConceptScore W3009688322C142724271 @default.
• W3009688322 hasConceptScore W3009688322C143409427 @default.
• W3009688322 hasConceptScore W3009688322C157767197 @default.
• W3009688322 hasConceptScore W3009688322C158846371 @default.
• W3009688322 hasConceptScore W3009688322C2778013878 @default.
• W3009688322 hasConceptScore W3009688322C2779651940 @default.
• W3009688322 hasConceptScore W3009688322C2780813603 @default.
• W3009688322 hasConceptScore W3009688322C2781192897 @default.
• W3009688322 hasConceptScore W3009688322C2909286980 @default.
• W3009688322 hasConceptScore W3009688322C42219234 @default.
• W3009688322 hasConceptScore W3009688322C541997718 @default.
• W3009688322 hasConceptScore W3009688322C71924100 @default.
• W3009688322 hasLocation W30096883221 @default.
• W3009688322 hasOpenAccess W3009688322 @default.
• W3009688322 hasPrimaryLocation W30096883221 @default.
• W3009688322 hasRelatedWork W136848763 @default.
• W3009688322 hasRelatedWork W1496590792 @default.
• W3009688322 hasRelatedWork W177653360 @default.
• W3009688322 hasRelatedWork W182864195 @default.
• W3009688322 hasRelatedWork W1973893428 @default.
• W3009688322 hasRelatedWork W1985533675 @default.
• W3009688322 hasRelatedWork W2002249773 @default.
• W3009688322 hasRelatedWork W2029292002 @default.
• W3009688322 hasRelatedWork W2052114958 @default.
• W3009688322 hasRelatedWork W2054146778 @default.
• W3009688322 hasRelatedWork W2060672842 @default.
• W3009688322 hasRelatedWork W2064046107 @default.
• W3009688322 hasRelatedWork W2084068128 @default.
• W3009688322 hasRelatedWork W2164557897 @default.
• W3009688322 hasRelatedWork W2169977266 @default.
• W3009688322 hasRelatedWork W2183167841 @default.
• W3009688322 hasRelatedWork W2361848737 @default.
• W3009688322 hasRelatedWork W2394247749 @default.
• W3009688322 hasRelatedWork W2413771867 @default.
• W3009688322 hasRelatedWork W3005741250 @default.
• W3009688322 isParatext "false" @default.
• W3009688322 isRetracted "false" @default.
• W3009688322 magId "3009688322" @default.
• W3009688322 workType "dissertation" @default.