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Clinical review: Prognostic value of magnetic resonance imaging in acute brain injury and coma.

Weiss N, Galanaud D, Carpentier A, Naccache L, Puybasset L - Crit Care (2007)

Bottom Line: This raises concerns about whether it is ethically appropriate to apply aggressive care routinely, which is also associated with burdensome long-term management costs.In addition, there is some evidence that MRI may have potential in terms of predicting outcome.Finally, the roles played by the main anatomical structures involved in arousal and awareness are discussed and avenues for future research suggested.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hopitaux de Paris and Pierre et Marie Curie University, Bd de l'hôpital, 75013, Paris, France.

ABSTRACT
Progress in management of critically ill neurological patients has led to improved survival rates. However, severe residual neurological impairment, such as persistent coma, occurs in some survivors. This raises concerns about whether it is ethically appropriate to apply aggressive care routinely, which is also associated with burdensome long-term management costs. Adapting the management approach based on long-term neurological prognosis represents a major challenge to intensive care. Magnetic resonance imaging (MRI) can show brain lesions that are not visible by computed tomography, including early cytotoxic oedema after ischaemic stroke, diffuse axonal injury after traumatic brain injury and cortical laminar necrosis after cardiac arrest. Thus, MRI increases the accuracy of neurological diagnosis in critically ill patients. In addition, there is some evidence that MRI may have potential in terms of predicting outcome. Following a brief description of the sequences used, this review focuses on the prognostic value of MRI in patients with traumatic brain injury, anoxic/hypoxic encephalopathy and stroke. Finally, the roles played by the main anatomical structures involved in arousal and awareness are discussed and avenues for future research suggested.

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FLAIR and T2* sequences in a patient with an arteriovenous malformation. (a) Axial fluid-attenuated inversion recovery (FLAIR) sequence showing hypersignal in the left temporal lobe. (b) Axial T2* sequence showing mild hyposignal in the same area suggestive of bleeding. (c) Different section of the axial FLAIR sequence showing hypersignal surrounded by hyposignal. Bleeding cannot be confirmed. (d) Axial T2* sequence clearly showing hyposignal lateral to the left putamen. The patient has bleeding from the arteriovenous malformation.
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Figure 1: FLAIR and T2* sequences in a patient with an arteriovenous malformation. (a) Axial fluid-attenuated inversion recovery (FLAIR) sequence showing hypersignal in the left temporal lobe. (b) Axial T2* sequence showing mild hyposignal in the same area suggestive of bleeding. (c) Different section of the axial FLAIR sequence showing hypersignal surrounded by hyposignal. Bleeding cannot be confirmed. (d) Axial T2* sequence clearly showing hyposignal lateral to the left putamen. The patient has bleeding from the arteriovenous malformation.

Mentions: Conventional MRI relies chiefly on four sequences [6]. Fluid-attenuated inversion recovery (FLAIR) is the primary sequence used in neuroradiology (Figure 1). It detects brain contusion, brain oedema and subarachnoid or intraventricular haemorrhage, as well as the resulting ventricular dilatation or herniation. The T2*-weighted sequence is more sensitive to intraparenchymal blood than is FLAIR. This sequence can also reveal haemorrhagic DAI [7,8]. The T2-weighted sequence completes the FLAIR sequence and provides greater detail on brainstem and central grey matter. Finally, diffusion weighted imaging (DWI) is sensitive to random movement of water molecules. This sequence shows cerebral oedema and distinguishes cytotoxic from vasogenic oedema. It is used chiefly in patients with ischaemic stroke.


Clinical review: Prognostic value of magnetic resonance imaging in acute brain injury and coma.

Weiss N, Galanaud D, Carpentier A, Naccache L, Puybasset L - Crit Care (2007)

FLAIR and T2* sequences in a patient with an arteriovenous malformation. (a) Axial fluid-attenuated inversion recovery (FLAIR) sequence showing hypersignal in the left temporal lobe. (b) Axial T2* sequence showing mild hyposignal in the same area suggestive of bleeding. (c) Different section of the axial FLAIR sequence showing hypersignal surrounded by hyposignal. Bleeding cannot be confirmed. (d) Axial T2* sequence clearly showing hyposignal lateral to the left putamen. The patient has bleeding from the arteriovenous malformation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2556735&req=5

Figure 1: FLAIR and T2* sequences in a patient with an arteriovenous malformation. (a) Axial fluid-attenuated inversion recovery (FLAIR) sequence showing hypersignal in the left temporal lobe. (b) Axial T2* sequence showing mild hyposignal in the same area suggestive of bleeding. (c) Different section of the axial FLAIR sequence showing hypersignal surrounded by hyposignal. Bleeding cannot be confirmed. (d) Axial T2* sequence clearly showing hyposignal lateral to the left putamen. The patient has bleeding from the arteriovenous malformation.
Mentions: Conventional MRI relies chiefly on four sequences [6]. Fluid-attenuated inversion recovery (FLAIR) is the primary sequence used in neuroradiology (Figure 1). It detects brain contusion, brain oedema and subarachnoid or intraventricular haemorrhage, as well as the resulting ventricular dilatation or herniation. The T2*-weighted sequence is more sensitive to intraparenchymal blood than is FLAIR. This sequence can also reveal haemorrhagic DAI [7,8]. The T2-weighted sequence completes the FLAIR sequence and provides greater detail on brainstem and central grey matter. Finally, diffusion weighted imaging (DWI) is sensitive to random movement of water molecules. This sequence shows cerebral oedema and distinguishes cytotoxic from vasogenic oedema. It is used chiefly in patients with ischaemic stroke.

Bottom Line: This raises concerns about whether it is ethically appropriate to apply aggressive care routinely, which is also associated with burdensome long-term management costs.In addition, there is some evidence that MRI may have potential in terms of predicting outcome.Finally, the roles played by the main anatomical structures involved in arousal and awareness are discussed and avenues for future research suggested.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hopitaux de Paris and Pierre et Marie Curie University, Bd de l'hôpital, 75013, Paris, France.

ABSTRACT
Progress in management of critically ill neurological patients has led to improved survival rates. However, severe residual neurological impairment, such as persistent coma, occurs in some survivors. This raises concerns about whether it is ethically appropriate to apply aggressive care routinely, which is also associated with burdensome long-term management costs. Adapting the management approach based on long-term neurological prognosis represents a major challenge to intensive care. Magnetic resonance imaging (MRI) can show brain lesions that are not visible by computed tomography, including early cytotoxic oedema after ischaemic stroke, diffuse axonal injury after traumatic brain injury and cortical laminar necrosis after cardiac arrest. Thus, MRI increases the accuracy of neurological diagnosis in critically ill patients. In addition, there is some evidence that MRI may have potential in terms of predicting outcome. Following a brief description of the sequences used, this review focuses on the prognostic value of MRI in patients with traumatic brain injury, anoxic/hypoxic encephalopathy and stroke. Finally, the roles played by the main anatomical structures involved in arousal and awareness are discussed and avenues for future research suggested.

Show MeSH
Related in: MedlinePlus