摘要
It is significantly important to define brain death with greater precision in terms of timing and accuracy. While in the past determination of brain death is simply based on conventional angiography, now with major technological advances the Diffusion-weighted MRI is a new method sensitive to cerebral ischemia which gives on the molecular level the deeply ischemic nature of the changes. Its value in brain death has been shown in various studies. In our study, we did a comparative overview of diffusion-weighted imaging (DWI) with and magnetic resonance angiography (MRA) considering the contribution of ADC measurements from brain parenchyma, in the patients diagnosed with brain death by clinical criteria. We studied 16 brain deaths in serial studies, in which there is a prominent difference between the white and gray matter ADC values on diffusion MRI. In the postmortem brains, ADC values comparing with the normal brain parenchyma, were reduced 65% in white matter and 42% in gray matter. Also, the patients’ ADC values of gray and white matter were significantly lower than those of irreversible brain-ischemia patients’ in ADC values. In comparison to most of the other studies, in our study population studied is large, in which is a comprehensive study that results consistent with the literature. As a result we propose that in the definition of brain death Diffusion MRI and ADC measurements are reliable to show diffuse ishemic changes of brain parenchyma.
It is significantly important to define brain death with greater precision in terms of timing and accuracy. While in the past determination of brain death is simply based on conventional angiography, now with major technological advances the Diffusion-weighted MRI is a new method sensitive to cerebral ischemia which gives on the molecular level the deeply ischemic nature of the changes. Its value in brain death has been shown in various studies. In our study, we did a comparative overview of diffusion-weighted imaging (DWI) with and magnetic resonance angiography (MRA) considering the contribution of ADC measurements from brain parenchyma, in the patients diagnosed with brain death by clinical criteria. We studied 16 brain deaths in serial studies, in which there is a prominent difference between the white and gray matter ADC values on diffusion MRI. In the postmortem brains, ADC values comparing with the normal brain parenchyma, were reduced 65% in white matter and 42% in gray matter. Also, the patients’ ADC values of gray and white matter were significantly lower than those of irreversible brain-ischemia patients’ in ADC values. In comparison to most of the other studies, in our study population studied is large, in which is a comprehensive study that results consistent with the literature. As a result we propose that in the definition of brain death Diffusion MRI and ADC measurements are reliable to show diffuse ishemic changes of brain parenchyma.
