jurnal
DESCRIPTION
jurnalTRANSCRIPT
Running head: TRAUMATIC BRAIN INJURY 1
Diagnosing and Managing Traumatic Brain Injuries
November 15th
, 2011
TRAUMATIC BRAIN INJURY 2
Abstract
Traumatic brain injuries are a serious and common occurrence in the United States. They are
one of the leading causes of death and can cause numerous long term effects on patients.
Imaging is one of the best ways to diagnose and manage a brain injury. There are five different
types of traumatic brain injuries and they are diagnosed using magnetic resonance imaging and
computed tomography. It is important for patients to receive quick and accurate images in order
to have the best possible outcome.
TRAUMATIC BRAIN INJURY 3
Diagnosing and Managing Traumatic Brain Injuries
Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity in
the world. “It is estimated that 10 million people sustain TBI each year worldwide, and the
Centers for Disease Control and Prevention in the USA estimates that 1.7 million people suffer
TBI annually” (Kim & Gean, 2011, p.39). The use of imaging is critical in the diagnosis and
management of these injuries. Computed tomography (CT) and magnetic resonance imaging
(MRI) are the most common imaging modalities used to diagnose and manage TBI.
Categories of Brain Injuries
The two different categories of injury when discussing TBI are primary and secondary.
The primary injuries, such as epidural hematoma, subdural hematoma, subarachnoid
hemorrhage, cortical contusion and traumatic axonal injury, are caused by the direct result of the
impact. The secondary injuries, such as cerebral swelling, herniation, and ischemia, can develop
minutes to days after the primary injury. “This classification highlights that TBI is not a one-
time event but rather a continuous and progressive injury that necessitates optimal medical and
surgical management to maximize patient recovery and prevent successive injury” (Kim & Gean,
2011, p.39).
Primary Injuries
Epidural Hematoma
An epidural hematoma (EDH) commonly occurs at the coup site, which is the site of
impact, and is usually accompanied with an overlying skull fracture. EDH is caused by an
"Injury to a meningeal artery/vein, diploic vein, or dural venous sinus result(ing) in a classically
lentiform-shaped collection of blood that strips the dura away from the inner table of the skull"
(Kim & Gean, 2011, p.40). The most common occurrence of EDHs are found in the temporal or
TRAUMATIC BRAIN INJURY 4
temporoparietal regions and are usually due to an injury of the middle meningeal artery, the
transverse/sigmoid sinus, or the sphenoparietal sinus. In rare occasions EDHs can occur in the
frontal region of the brain, opposite of the trauma site. These are called contrecoup EDHs and
only nine cases have been reported in literature.
EDHs are more common in males than females, with the ratio being 4:1. The peak
incidence is within a mean age of 20-30 years, and is rare in patients older than 50 years. It is
very uncommon for a delayed EDH to occur, “with a reported incidence of approximately 3%”
(Takeuchi, Takasato, Masaoka, & Otani, 2010, p.152).
Imaging epidural hematomas
When imaging EDHs,
the preferred modality is CT.
The hematoma in the images
typically appear to be
lentiform or biconvex in
shape. (See Fig. 1) EDHs do
not cross cranial sutures, but
are able to cross the midline.
This is one way to distinguish an
EDH from the various other
hematomas (Kim & Gean, 2011).
Subdural Hematoma
A subdural hematoma (SDH) usually occurs at the contrecoup site, even though it can
occur at the coup site. SDH’s are caused by an "Injury to superficial bridging veins results in
Fig. 1 A. Epidural hematoma beneath a skull fracture. B.
Arrow pointing to the skull fracture.
Note. Kim, J.J. & Gean, A.D. (2011). Imaging for the diagnosis and
management of traumatic brain injury. Neurotherapeutics, 8(1), 39-53.
Retrieved on November 4, 2011, from doi:10.1007/s13311-010-0003-
3
TRAUMATIC BRAIN INJURY 5
bleeding between the meningeal layer of the dura and arachnoid, and blood may continue to
accumulate in this space" (Kim & Gean, 2011, p.41). Some of the common places for SDHs to
occur are over the cerebral convexities, along the tentorium cerebelli, and along the flax cerebri.
According to Cantu and Gean (2010) "an acute SDH is the most common cause of death due to
head injury in sports" (p.1561). SDHs are believed to be
caused by the acceleration/deceleration forces that
accompany these injuries.
Imaging subdural hematomas
A SDH will appear crescent in shape and can be
extremely subtle, so window settings and adjustments are
crucial in diagnosing. SDH's are able to cross cranial suture
lines, but do not cross the midline, which is the opposite of
an EDH. It is common for an SDH to cause a
shift in the midline. (See Fig. 2) "The volume of
the extra-axial collection is proportional to the
extent of mass effect and midline shift" (Cantu &
Gean, 2010, p.1562).
Subarachnoid Hemorrhage
A Subarachnoid hemorrhage (SAH) occurs in nearly half of patients that suffer a large
head injury and can commonly be associated with other types of hemorrhages. "SAH may result
from direct laceration of the small cortical vessels traversing the subarachnoid space,
redistribution of intraventricular hemorrhage exiting the fourth ventricular outflow foramen, or
direct extension from cortical contusion/hematoma" (Kim & Gean, 2011, p.43). The blood that
Fig.2 A CT image of a SDH on the left
side. The image shows a midline shift
that is common in a SDH.
Cantu, R.C. & Gean, A.D. (2010). Second-impact
syndrome and a small subdural hematoma: an
uncommon catastrophic result of repetitive head
injury with a characteristic imaging appearance.
Journal of Neurotrauma, 27(9), 1557-1564.
Retrieved November 4, 2011, from
doi:10.1089/neu.2010.1334
TRAUMATIC BRAIN INJURY 6
fills the subarachnoid space causes a rise in intracranial pressure and displaces the cerebrospinal
fluid. According to Sehba, Pluta, and Zhang (2010), this moment of increased pressure is
usually described by patients as "the worst headache of my life" (p.28) .
Imaging subarachnoid hemorrahages
An SAH is observed on CT images as linear
areas of high attenuation. (See Fig. 3) They can be
found in the cerebral sulci, Sylvian fissures, or basilar
cisterns. Some patients with TBIs may only have a
small SAH as the only abnormal finding on a CT scan,
so it is crucial to identify them accurately. Patients that
have an accompanying SAH with other TBI's have a
significantly worse outcome and are less likely to
achieve a good recovery in comparison with the
TBI's that are not accompanied with SAH (Kim &
Gean, 2011).
Cerebral Contusion
A cerebral contusion (CC) can be caused by either direct trauma or
acceleration/deceleration injury. CCs usually occur at the contrecoup site and are caused when a
moving head collides with a stationary object. Although CC's can occur at the coup site beneath
a skull fracture, they are more common and severe in contrecoup injuries. CC's are commonly
referred to as a bruise in the brain that are caused by the rough and irregular surfaces of the skull.
These impacts with the skull cause hemorrhagic contusions (Kim & Gean, 2011).
Fig. 3 A CT image of a SAH. The arrow
head shows the linear areas.
Note. Kim, J.J. & Gean, A.D. (2011). Imaging for
the diagnosis and management of traumatic brain
injury. Neurotherapeutics, 8(1), 39-53. Retrieved
on November 4, 2011, from doi:10.1007/s13311-
010-0003-3
TRAUMATIC BRAIN INJURY 7
Imaging cortical contusions
A CC can be imaged
using CT or MRI, but MRI is
more sensitive in detecting
small hemorrhagic contusions.
CC's appear as "small, focal
areas of pepechial hemorrhage
peripherally located in the
brain" (Kim & Gean, 2011, p.43).
They can be very subtle on the
initial CT scan, but about half of
contusions will evolve and grow
larger over time. (See Fig. 4) Due
to the evolving of CC's it is crucial that serial CT imaging and close monitoring of patients is
done.
Traumatic Axonal Injury
A Traumatic axonal injury (TAI) is typically caused by extreme
acceleration/deceleration or by child abuse, such as shaking baby syndrome. TAI involves the
loss of neural function in the areas of the brain where white and grey matter meet, which is
usually away from the area of direct trauma with the skull. The white matter in the brain is
denser than the gray matter, "due to the different inertial characteristics based on these densities,
as the brain rotates during acceleration-deceleration events, lower density tissues move more
rapidly than those of greater density. This velocity difference causes sheering of neuronal
Fig. 4 A. The initial CT scan of a patient, the short
arrow is pointing to a small CC. B. A CT scan of the
same patient 6 hours later, the short arrows pointing to a
much larger CC.
Note. Kim, J.J. & Gean, A.D. (2011). Imaging for the diagnosis and
management of traumatic brain injury. Neurotherapeutics, 8(1), 39-
53. Retrieved on November 4, 2011, from doi:10.1007/s13311-010-
0003-3
TRAUMATIC BRAIN INJURY 8
axons" (Shipley, 2011, para. 4). This process is usually bilateral, covers a large area and is near
the cerebral cortex, corpus callosum, or brain stem (Kim & Gean, 2011).
Imaging traumatic axonal injuries
The most diagnostic imaging modality for TAI is
MRI, due to CT being insensitive to white matter lesions.
Most CT scans show up normal with TAI injuries because
they are nonhemorrhagic (Marquez de la Plata et al., 2011).
TAI usually shows up on the MRI as multifocal areas of
abnormal signal in the white matter. (See Fig. 5) Many
studies have indicated that MRI can predict the
length of coma in TAI patients. "The volume of
white-matter lesions has been correlated to the
degree of injury, as measured by MRI"
(Wasserman, 2011, para. 5).
Secondary Injuries
Cerebral Swelling
The cause of cerebral swelling can be either cerebral edema or cerebral hyperemia.
Cerebral hyperemia is due to "Dysautoregulation with vascular engorgement and increased
cerebral blood volume" (Kim & Gean, 2011, p.46). This was believed to be the main mechanism
that caused cerebral swelling. Some of the recent studies have suggested that the main causes of
cerebral swelling are due to edema, which is "due to the failure of cell membrane pumps,
resulting in intracellular water leakage" (Kim & Gean, 2011, p.46). Images of cerebral swelling
Fig. 5 An MRI of a patient with a TAI,
the arrows are pointing to the abnormal
signal in the white matter.
Note. Kim, J.J. & Gean, A.D. (2011). Imaging for
the diagnosis and management of traumatic brain
injury. Neurotherapeutics, 8(1), 39-53. Retrieved
on November 4, 2011, from doi:10.1007/s13311-
010-0003-3
TRAUMATIC BRAIN INJURY 9
due to hyperemia appear as the loss of sulci, with gray and white matter differentiation intact.
(See Fig. 6) Images of cerebral edema with
appear as the loss of gray and white matter.
Cerebral Herniation
Cerebral herniation is due to part of
the brain being compressed by a hematoma.
This causes part of the brain to move from
one compartment of the cranium to
another. Subfalcial herniation, uncal
herniation, and cerebellar tonsillar
herniation are the three major types of
herniation that can occur separately or in
combination (Agamanolis, n.d.). Patients that suffer from herniation "typically undergo
decompressive craniectomy with mass lesion evacuation" (Kim & Gean, 2011, p.47).
Cerebral Ischemia and Infarction
Cerebral ischemia and infarction are not very common in
TBI patients, but occasionally they are present on CT scans.
Ischemia is usually due to a blood vessel being compressed by a
cerebral herniation. (See Fig. 7) Infarctions are common in the
anterior or posterior cerebral artery following a subfalcine or uncal
Fig. 6 A and B are CT images of a patient with
cerebral swelling. Both images show
differentiation in gray and white matter, with loss
of sulci.
Note. Kim, J.J. & Gean, A.D. (2011). Imaging for the
diagnosis and management of traumatic brain injury.
Neurotherapeutics, 8(1), 39-53. Retrieved on November 4,
2011, from doi:10.1007/s13311-010-0003-3
Fig. 7 A CT image that has bilateral multifocal ischemic lesions.
Cantu, R.C. & Gean, A.D. (2010). Second-impact syndrome and a small subdural hematoma: an
uncommon catastrophic result of repetitive head injury with a characteristic imaging appearance. Journal of
Neurotrauma, 27(9), 1557-1564. Retrieved November 4, 2011, from doi:10.1089/neu.2010.1334
TRAUMATIC BRAIN INJURY 10
herniation (Kim & Gean, 2011). MRI and CT are able to provide a vast amount of information
and assessment of the size, location, and severity of cerebral ischemia and infarctions (Leiva-
Salinas, Wintermark, & Kidwell, 2011).
Imaging traumatic brain injuries
Imaging plays an important role in diagnosing and managing TBI’s. It is critical that the
right images are taken and the best modality is used to properly diagnose an injury. According to
Kim and Gean (2011):
For diagnosis of TBI in the acute setting, noncontrast CT is the modality of choice
as it quickly and accurately identifies intracranial hemorrhage that warrants neurosurgical
evacuation. CT readily identifies both extra-axial hemorrhage (epidural, subdural, and
subarachnoid/intraventricular hemorrhage) and intra axial hemorrhage (cortical
contusion, intraparenchymal hematoma, and TAI or shear injury). While CT is the
mainstay of TBI imaging in the acute setting, magnetic resonance imaging (MRI) has
better diagnostic sensitivity for certain types of injuries that are not necessarily
hemorrhagic (p.40).
Both CT and MRI are used in the prognosis and management of TBI and advancements
are continually made to increase the quality of the images.
Conclusion
In conclusion, CT and MRI are crucial in diagnosing and managing TBI. The images that CT
and MRI provide are important in identifying the acute primary injuries when making a
diagnosis and identifying secondary injuries to guide the management process. Due to the large
number of individuals that suffer from TBI, it is imperative that high quality images are
produced to provide the best possible treatment for patients.
TRAUMATIC BRAIN INJURY 11
References
Agamanolis, D.P., (n.d.) Traumatic brain injury and increased intracranial pressure.
Neuropathology Web site. Retrieved from http://neuropathology-web.org/chapter4/
chapter4cHerniations.html#herniations
Cantu, R.C. & Gean, A.D. (2010). Second-impact syndrome and a small subdural hematoma: An
uncommon catastrophic result of repetitive head injury with a characteristic imaging
appearance. Journal of Neurotrauma, 27(9), 1557-1564. doi:10.1089/neu.2010.1334
Kim, J.J. & Gean, A.D. (2011). Imaging for the diagnosis and management of traumatic brain
injury. Neurotherapeutics, 8(1), 39-53. doi:10.1007/s13311-010-0003-3
Leiva-Salinas, C., Wintermark, M., & Kidwell, C.S. (2011). Neuroimaging of cerebral ischemia
and infarction. Neurotheraputics, 8(1), 19-27. Retrieved from
http://www.springerlink.com/content/k0125231757l8v13/fulltext.pdf
Marquez de la Plata, C.D., Garces, J., Kojori, E.S., Grinnan, J., Krishnan, K., Pidikiti, R.,
…Diaz-Arrastia, R. (2011). Deficits in functional connectivity of hippocampal and
frontal lobe circuits after traumatic axonal injury. Archives of Neurology, 68(1), 74-84.
doi:10.1001/archneurol.2010.342
Sehba, F.A., Pluta, R.M., & Zhang, J.H. (2011). Metamorphosis of subarachnoid hemorrhage
research: from delayed vasospasm to early brain injury. Mol Neruobiol, 43(1), 27-
40. doi:10.1007/s12035-010-8155-z
Shipley, C. (2010). Traumatic brain injury and diffuse axonal injury. Trial Image Inc. Web site.
Retrieved from http://trialimagestore.com/article_traumatic_brain_injury.html
Takeuchi, S., Takasato, Y., Masaoka, H., & Otani, N. (2010). Contrecoup epidural hematoma.
Neurology India, 58(1), 152-154. doi:10.4103/0028-3886.60425
Wasserman, J.R. (2011). Diffuse axonal injury imaging. Retrieved from
TRAUMATIC BRAIN INJURY 12
http://emedicine.medscape.com/article/339912-overview#a21