Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia
This thesis describes the results of a study to investigate early cerebral changes in a piglet model of perinatal asphyxia using quantitative diffusion-weighted imaging (DWI) and subsequent work to develop a robust DWI technique to enable similar studies to be performed in neonates. 31Phophorus magn...
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ndltd-bl.uk-oai-ethos.bl.uk-3955612015-03-19T04:15:47ZQuantitative diffusion weighted imaging : techniques and applications to perinatal asphyxiaNguyen, Quyen2001This thesis describes the results of a study to investigate early cerebral changes in a piglet model of perinatal asphyxia using quantitative diffusion-weighted imaging (DWI) and subsequent work to develop a robust DWI technique to enable similar studies to be performed in neonates. 31Phophorus magnetic resonance spectroscopy and quantitative diffusion and T2 imaging of the cerebrum were performed in a piglet model of perinatal asphyxia. A significant decline in the ratio of phosphocreatine to inorganic phosphate concentrations ([PCr]/[Pi]) was observed during the 48 hours following the transient hypoxicischaemic (H-I) insult. The global directionally averaged apparent diffusion coefficient (ADCav) also declined significantly during the same period and a strong correlation between the [PCr]/[Pi] and ADCav was found. Strong regional and temporal variations in the cerebral response were observed following the H-I insult. In the basal ganglia and parasagittal cortex, significant decline in ADCs was seen approximately 8 hours after the H-I insult. In the thalamus, internal capsule, periventricular white matter and medial cortex, significant ADCs decline was not observed until 32 hours following the H-I insult. A significant T2 increase was observed in the internal capsule but not in the other regions of interest. To enable clinical DWI to be performed in neonates a novel `reacquisition' technique that overcomes the problem of motion artefact in DWI is presented. The reacquisition technique involves the automatic detection and reacquisition of motion-corrupted data in real-time. Computer simulations were used to demonstrate that motion-corrupted data may be detected accurately and reacquired in a time efficient manner. The reacquisition technique was implemented on a Bruker AVANCE scanner in combination with a spinecho 2DFT DWI sequence and an interleaved EPI DWI sequence. The effectiveness of the technique was demonstrated with both a computer-controlled motion phantom and neonates from an ongoing study of perinatal asphyxia.618.92University College London (University of London)http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395561http://discovery.ucl.ac.uk/1382401/Electronic Thesis or Dissertation |
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618.92 Nguyen, Quyen Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
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This thesis describes the results of a study to investigate early cerebral changes in a piglet model of perinatal asphyxia using quantitative diffusion-weighted imaging (DWI) and subsequent work to develop a robust DWI technique to enable similar studies to be performed in neonates. 31Phophorus magnetic resonance spectroscopy and quantitative diffusion and T2 imaging of the cerebrum were performed in a piglet model of perinatal asphyxia. A significant decline in the ratio of phosphocreatine to inorganic phosphate concentrations ([PCr]/[Pi]) was observed during the 48 hours following the transient hypoxicischaemic (H-I) insult. The global directionally averaged apparent diffusion coefficient (ADCav) also declined significantly during the same period and a strong correlation between the [PCr]/[Pi] and ADCav was found. Strong regional and temporal variations in the cerebral response were observed following the H-I insult. In the basal ganglia and parasagittal cortex, significant decline in ADCs was seen approximately 8 hours after the H-I insult. In the thalamus, internal capsule, periventricular white matter and medial cortex, significant ADCs decline was not observed until 32 hours following the H-I insult. A significant T2 increase was observed in the internal capsule but not in the other regions of interest. To enable clinical DWI to be performed in neonates a novel `reacquisition' technique that overcomes the problem of motion artefact in DWI is presented. The reacquisition technique involves the automatic detection and reacquisition of motion-corrupted data in real-time. Computer simulations were used to demonstrate that motion-corrupted data may be detected accurately and reacquired in a time efficient manner. The reacquisition technique was implemented on a Bruker AVANCE scanner in combination with a spinecho 2DFT DWI sequence and an interleaved EPI DWI sequence. The effectiveness of the technique was demonstrated with both a computer-controlled motion phantom and neonates from an ongoing study of perinatal asphyxia. |
author |
Nguyen, Quyen |
author_facet |
Nguyen, Quyen |
author_sort |
Nguyen, Quyen |
title |
Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
title_short |
Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
title_full |
Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
title_fullStr |
Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
title_full_unstemmed |
Quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
title_sort |
quantitative diffusion weighted imaging : techniques and applications to perinatal asphyxia |
publisher |
University College London (University of London) |
publishDate |
2001 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395561 |
work_keys_str_mv |
AT nguyenquyen quantitativediffusionweightedimagingtechniquesandapplicationstoperinatalasphyxia |
_version_ |
1716736980052606976 |