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Brain Herniation Imaging

  • Author: Margaret Loh-Lee, MD; Chief Editor: L Gill Naul, MD  more...
 
Updated: Aug 12, 2015
 

Overview

The brain is an organ of immense complexity. In the cranium, dural reflections and bony landmarks divide the brain into anatomic regions. Brain herniation represents mechanical displacement of normal brain relative to another anatomic region secondary to mass effect from traumatic, neoplastic, ischemic, or infectious etiologies. See the images below.

Nonenhanced head computed tomography (CT) scan at Nonenhanced head computed tomography (CT) scan at the level of the lateral ventricles was obtained in a 78-year-old man who presented with respiratory failure. The image demonstrates a large right frontal and temporal subdural fluid collection with hyperattenuating and hypoattenuating components consistent with an acute on chronic subdural hematoma. Subfalcine herniation, midline shift, effacement of the ipsilateral lateral ventricle, and enlargement of the contralateral occipital horn are present.
Nonenhanced head computed tomography scan at the l Nonenhanced head computed tomography scan at the level of the suprasellar cistern in the same patient as in the previous image. A large right frontotemporal subdural hematoma is exerting mass effect on the right frontal and temporal lobes, with resultant effacement of the suprasellar cistern and with right-sided uncal herniation. Mass effect from the subdural hematoma effaces the ipsilateral temporal horn, causing dilatation of the contralateral temporal horn. Subfalcine herniation and narrowing of the contralateral ambient and quadrigeminal plate cisterns are present.
Nonenhanced head computed tomography (CT) scan obt Nonenhanced head computed tomography (CT) scan obtained at the level of the inferior pons in the same patient as in the previous 2 images. Acute-on-chronic right temporal subdural hematoma exerts mass effect on the right temporal lobe, causing ipsilateral temporal horn, with effacement and dilatation of the contralateral temporal horn. Narrowing of the contralateral ambient and quadrigeminal plate cisterns is present, with ipsilateral widening of the ambient and quadrigeminal cisterns.

Herniations of the brain are divided into 5 major categories, as follows:

  • Transtentorial herniation [1]
  • Subfalcine/cingulate herniation
  • Foramen magnum/tonsillar herniation (seen in patients with Arnold-Chiari malformation, as demonstrated in the images below) [2, 3, 4, 5]
    T1-weighted sagittal magnetic resonance image thro T1-weighted sagittal magnetic resonance image through the cervical spine in a child with a history of an Arnold-Chiari I malformation. Image shows tonsillar herniation with compression of the central canal at the craniocervical junction and resultant syringohydromyelia in the visualized portion of the cervical spinal cord.
    T2-weighted sagittal magnetic resonance image thro T2-weighted sagittal magnetic resonance image through the cervical spine was obtained in the same patient as in the previous image. The cerebellar tonsils are projecting inferiorly below the level of the opisthion, with compression of the central canal at the craniocervical junction. Hyperintense syringohydromyelia in the visualized portion of the cervical spinal cord is demonstrated.
  • Sphenoid/alar herniation
  • Extracranial herniation

Each category of herniation is associated with a specific neurologic syndrome.

Preferred examination

For transtentorial herniation, computed tomography (CT) scanning or magnetic resonance imaging (MRI) is useful for evaluation. MRI can provide axial, as well as sagittal and coronal, views.

For subfalcine/cingulate herniation, CT scanning or MRI is again useful for evaluation, with MRI able to provide axial, sagittal, and coronal views.

For foramen magnum/tonsillar herniation, MRI provides the best visualization on sagittal and coronal views. However, because patients with this type of herniation often present acutely, axial CT scanning enables visualization of this condition.

For sphenoid/alar herniation, MRI provides the best visualization on parasagittal images. However, axial CT scanning or MRI can demonstrate anterior displacement of the ipsilateral middle cerebral artery, which is an indirect sign of sphenoid herniation.[6, 7]

For extracranial herniation, CT scanning or MRI is useful for evaluation.

A study by Probst et al found that among 161 patients with frank brain herniation diagnosed by CT scan, 3 (1.9%) had no neurologic deficit. The authors sought to determine if some patients with brain herniation or significant brain shift diagnosed by cranial CT might have a normal neurologic examination. Using cranial CT scan radiology reports, CT scans were classified into 3 categories: frank herniation, significant shift without frank herniation, and minimal or no shift. The investigators also found that of 91 patients with significant brain shift but no herniation, 4 (4.4%) had no neurologic deficit.[8]

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Computed Tomography

With a descending transtentorial herniation, mass effect in the cerebrum pushes the supratentorial brain through the incisura.[9]

With ascending transtentorial herniation, mass effect from the posterior fossa pushes the infratentorial brain through the incisura (as seen below). This results in the distortion of the midbrain, flattening of the posterior quadrigeminal plate, and narrowing of the bilateral ambient cisterns. Hydrocephalus is frequently noted.

With subfalcine/cingulate herniation (seen below), the supratentorial brain is displaced underneath the anterior falx.

Nonenhanced head computed tomography (CT) scan at Nonenhanced head computed tomography (CT) scan at the level of the lateral ventricles was obtained in a 78-year-old man who presented with respiratory failure. The image demonstrates a large right frontal and temporal subdural fluid collection with hyperattenuating and hypoattenuating components consistent with an acute on chronic subdural hematoma. Subfalcine herniation, midline shift, effacement of the ipsilateral lateral ventricle, and enlargement of the contralateral occipital horn are present.
Nonenhanced head computed tomography scan at the l Nonenhanced head computed tomography scan at the level of the suprasellar cistern in the same patient as in the previous image. A large right frontotemporal subdural hematoma is exerting mass effect on the right frontal and temporal lobes, with resultant effacement of the suprasellar cistern and with right-sided uncal herniation. Mass effect from the subdural hematoma effaces the ipsilateral temporal horn, causing dilatation of the contralateral temporal horn. Subfalcine herniation and narrowing of the contralateral ambient and quadrigeminal plate cisterns are present.
Nonenhanced head computed tomography (CT) scan obt Nonenhanced head computed tomography (CT) scan obtained at the level of the inferior pons in the same patient as in the previous 2 images. Acute-on-chronic right temporal subdural hematoma exerts mass effect on the right temporal lobe, causing ipsilateral temporal horn, with effacement and dilatation of the contralateral temporal horn. Narrowing of the contralateral ambient and quadrigeminal plate cisterns is present, with ipsilateral widening of the ambient and quadrigeminal cisterns.

With foramen magnum/tonsillar herniation, the infratentorial brain is displaced through the foramen magnum.

With sphenoid/alar herniations, the supratentorial brain is sliding anteriorly or posteriorly over the wing of the sphenoid bone. An anterior herniation occurs when the temporal lobe herniates anteriorly and superiorly over the sphenoid bone. Conversely, a posterior herniation occurs when the frontal lobe herniates posteriorly and inferiorly over the sphenoid bone.

With extracranial herniation, the brain is displaced through a cranial defect, as in the image below.

Nonenhanced computed tomography (CT) scan of the b Nonenhanced computed tomography (CT) scan of the brain at the level of the body of the lateral ventricles was obtained in a 37-year-old man who underwent a right frontotemporal decompression craniectomy for a large right frontal hematoma after a skiing accident. A focal hypoattenuating infarct is seen in the right frontal lobe, with an adjacent edematous brain parenchyma herniating through the right frontotemporal craniectomy defect. The patient had communicating hydrocephalus with dilatation of the lateral ventricles.

Cross-sectional imaging provides a high degree of confidence.

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Magnetic Resonance Imaging

With descending transtentorial herniation, mass effect in the cerebrum pushes the supratentorial brain through the incisura.

In ascending transtentorial herniation (seen in the images below), mass effect from the posterior fossa pushes the infratentorial brain through the incisura. This results in the distortion of the midbrain, flattening of the posterior quadrigeminal plate, and narrowing of the bilateral ambient cisterns. Hydrocephalus is frequently noted.[10]

Right parasagittal gadolinium-enhanced T1-weighted Right parasagittal gadolinium-enhanced T1-weighted magnetic resonance image in a 9-year-old girl with a history of right cerebellar astrocytoma who presented with headaches and vomiting. Heterogeneously enhancing mass is demonstrated in the right cerebellum, with compression of the adjacent brainstem and fourth ventricle. Ascending transtentorial herniation of the cerebellum is demonstrated through the incisura. Descending tonsillar herniation also is present.
Axial gadolinium-enhanced T1-weighted magnetic res Axial gadolinium-enhanced T1-weighted magnetic resonance image obtained at the level of the midbrain in the same patient as in the previous image. A heterogeneously enhancing mass is seen in the right medial anterior cerebellum, with mass effect on the right posterior lateral midbrain and fourth ventricle. The image shows enlargement of the temporal horns of both lateral ventricles as a result of obstruction by the cerebellar mass at the level of the fourth ventricle.

Subfalcine/cingulate herniation causes the supratentorial brain to be displaced underneath the anterior falx.

In foramen magnum/tonsillar herniation, the infratentorial brain is displaced through the foramen magnum, as demonstrated below.

T1-weighted sagittal magnetic resonance image thro T1-weighted sagittal magnetic resonance image through the cervical spine in a child with a history of an Arnold-Chiari I malformation. Image shows tonsillar herniation with compression of the central canal at the craniocervical junction and resultant syringohydromyelia in the visualized portion of the cervical spinal cord.
T2-weighted sagittal magnetic resonance image thro T2-weighted sagittal magnetic resonance image through the cervical spine was obtained in the same patient as in the previous image. The cerebellar tonsils are projecting inferiorly below the level of the opisthion, with compression of the central canal at the craniocervical junction. Hyperintense syringohydromyelia in the visualized portion of the cervical spinal cord is demonstrated.

With sphenoid/alar herniations, the supratentorial brain slides either anteriorly or posteriorly over the wing of the sphenoid bone. An anterior herniation occurs when the temporal lobe herniates anteriorly and superiorly over the sphenoid bone. Conversely, a posterior herniation occurs when the frontal lobe herniates posteriorly and inferiorly over the sphenoid bone.

Extracranial herniation causes the brain to be displaced through a cranial defect.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Systemic Fibrosis. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or magnetic resonance angiography (MRA) scans.  For more information, see Medscape.

Cross-sectional imaging provides a high degree of confidence.

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Ultrasonography

Neonatal intracranial ultrasonography may have a limited role.[11]

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Angiography

Vascular displacement from mass effect associated with herniation can be seen on cerebral angiograms. Specifically, deep venous anatomic distortion aids in identifying these entities, although CT scanning and MRI are the currently favored diagnostic modalities.

The degree of confidence is high when classic displacement of the deep venous structures is seen.

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Contributor Information and Disclosures
Author

Margaret Loh-Lee, MD Staff Physician, Department of Radiology, Santa Clara Valley Medical Center

Margaret Loh-Lee, MD is a member of the following medical societies: Radiological Society of North America

Disclosure: Nothing to disclose.

Coauthor(s)

Mahesh R Patel, MD Chief of MRI, Department of Diagnostic Imaging, Santa Clara Valley Medical Center

Mahesh R Patel, MD is a member of the following medical societies: American Roentgen Ray Society, American Society of Neuroradiology, Radiological Society of North America

Disclosure: Nothing to disclose.

Specialty Editor Board

Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand

Disclosure: Nothing to disclose.

Robert L DeLaPaz, MD Director, Professor, Department of Radiology, Division of Neuroradiology, Columbia University College of Physicians and Surgeons

Robert L DeLaPaz, MD is a member of the following medical societies: American Society of Neuroradiology, Association of University Radiologists, Radiological Society of North America

Disclosure: Nothing to disclose.

Chief Editor

L Gill Naul, MD Professor and Head, Department of Radiology, Texas A&M University College of Medicine; Chair, Department of Radiology, Baylor Scott and White Healthcare, Central Division

L Gill Naul, MD is a member of the following medical societies: American College of Radiology, American Medical Association, American Roentgen Ray Society, Radiological Society of North America

Disclosure: Nothing to disclose.

Additional Contributors

Chi-Shing Zee, MD Chief of Neuroradiology, Professor, Departments of Radiology and Neurosurgery, Keck School of Medicine of the University of Southern California

Chi-Shing Zee, MD is a member of the following medical societies: American Society of Neuroradiology

Disclosure: Nothing to disclose.

References
  1. Koenig MA, Bryan M, Lewin JL 3rd, Mirski MA, Geocadin RG, Stevens RD. Reversal of transtentorial herniation with hypertonic saline. Neurology. 2008 Mar 25. 70(13):1023-9. [Medline].

  2. Aquilina K, Merchant TE, Boop FA, Sanford RA. Chiari I malformation after cranial radiation therapy in childhood: a dynamic process associated with changes in clival growth. Childs Nerv Syst. 2009 Nov. 25(11):1429-36. [Medline].

  3. Leikola J, Koljonen V, Valanne L, Hukki J. The incidence of Chiari malformation in nonsyndromic, single suture craniosynostosis. Childs Nerv Syst. 2009 Dec 16. [Medline].

  4. Meadows J, Kraut M, Guarnieri M, et al. Asymptomatic Chiari type I malformations identified on magnetic resonance imaging. J Neurosurg. 2000 Jun. 92(6):920-6. [Medline].

  5. Cesmebasi A, Loukas M, Hogan E, Kralovic S, Tubbs RS, Cohen-Gadol AA. The Chiari malformations: a review with emphasis on anatomical traits. Clin Anat. 2015 Mar. 28 (2):184-94. [Medline].

  6. Chotai S, Kim JH, Kim JH, Kwon TH. Brain herniation induced by drainage of subdural hematoma in spontaneous intracranial hypotension. Asian J Neurosurg. 2013 Apr. 8(2):112-5. [Medline]. [Full Text].

  7. Moon W, Joo W, Chough J, Park H. Spontaneous spinal subdural hematoma concurrent with cranial subdural hematoma. J Korean Neurosurg Soc. 2013 Jul. 54(1):68-70. [Medline]. [Full Text].

  8. Probst MA, Baraff LJ, Hoffman JR, Wolfson AB, Ourian AJ, Mower WR. Can patients with brain herniation on cranial computed tomography have a normal neurologic exam?. Acad Emerg Med. 2009 Feb. 16(2):145-50. [Medline].

  9. Yuh EL, Gean AD, Manley GT, Callen AL, Wintermark M. Computer-aided assessment of head computed tomography (CT) studies in patients with suspected traumatic brain injury. J Neurotrauma. 2008 Oct. 25(10):1163-72. [Medline].

  10. Jang SH, Kim DS, Son SM, et al. Clinical application of diffusion tensor tractography for elucidation of the causes of motor weakness in patients with traumatic brain injury. NeuroRehabilitation. 2009. 24(3):273-8. [Medline].

  11. Bor-Seng-Shu E, Paiva WS, Figueiredo EG, Fujimoto Y, de Andrade AF, Fonoff ET, et al. Posttraumatic refractory intracranial hypertension and brain herniation syndrome: cerebral hemodynamic assessment before decompressive craniectomy. Biomed Res Int. 2013. 2013:750809. [Medline].

 
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Nonenhanced head computed tomography (CT) scan at the level of the lateral ventricles was obtained in a 78-year-old man who presented with respiratory failure. The image demonstrates a large right frontal and temporal subdural fluid collection with hyperattenuating and hypoattenuating components consistent with an acute on chronic subdural hematoma. Subfalcine herniation, midline shift, effacement of the ipsilateral lateral ventricle, and enlargement of the contralateral occipital horn are present.
Nonenhanced head computed tomography scan at the level of the suprasellar cistern in the same patient as in the previous image. A large right frontotemporal subdural hematoma is exerting mass effect on the right frontal and temporal lobes, with resultant effacement of the suprasellar cistern and with right-sided uncal herniation. Mass effect from the subdural hematoma effaces the ipsilateral temporal horn, causing dilatation of the contralateral temporal horn. Subfalcine herniation and narrowing of the contralateral ambient and quadrigeminal plate cisterns are present.
Nonenhanced head computed tomography (CT) scan obtained at the level of the inferior pons in the same patient as in the previous 2 images. Acute-on-chronic right temporal subdural hematoma exerts mass effect on the right temporal lobe, causing ipsilateral temporal horn, with effacement and dilatation of the contralateral temporal horn. Narrowing of the contralateral ambient and quadrigeminal plate cisterns is present, with ipsilateral widening of the ambient and quadrigeminal cisterns.
Right parasagittal gadolinium-enhanced T1-weighted magnetic resonance image in a 9-year-old girl with a history of right cerebellar astrocytoma who presented with headaches and vomiting. Heterogeneously enhancing mass is demonstrated in the right cerebellum, with compression of the adjacent brainstem and fourth ventricle. Ascending transtentorial herniation of the cerebellum is demonstrated through the incisura. Descending tonsillar herniation also is present.
Axial gadolinium-enhanced T1-weighted magnetic resonance image obtained at the level of the midbrain in the same patient as in the previous image. A heterogeneously enhancing mass is seen in the right medial anterior cerebellum, with mass effect on the right posterior lateral midbrain and fourth ventricle. The image shows enlargement of the temporal horns of both lateral ventricles as a result of obstruction by the cerebellar mass at the level of the fourth ventricle.
Nonenhanced computed tomography (CT) scan of the brain at the level of the body of the lateral ventricles was obtained in a 37-year-old man who underwent a right frontotemporal decompression craniectomy for a large right frontal hematoma after a skiing accident. A focal hypoattenuating infarct is seen in the right frontal lobe, with an adjacent edematous brain parenchyma herniating through the right frontotemporal craniectomy defect. The patient had communicating hydrocephalus with dilatation of the lateral ventricles.
T1-weighted sagittal magnetic resonance image through the cervical spine in a child with a history of an Arnold-Chiari I malformation. Image shows tonsillar herniation with compression of the central canal at the craniocervical junction and resultant syringohydromyelia in the visualized portion of the cervical spinal cord.
T2-weighted sagittal magnetic resonance image through the cervical spine was obtained in the same patient as in the previous image. The cerebellar tonsils are projecting inferiorly below the level of the opisthion, with compression of the central canal at the craniocervical junction. Hyperintense syringohydromyelia in the visualized portion of the cervical spinal cord is demonstrated.
 
 
 
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