Trauma

12

Trauma


Traumatic Brain Injury


Overview


Head CT indications in the trauma setting:


GCS <15 two hours after injury or any GCS deterioration


Suspected skull fractures


Signs of basal skull fracture


Loss of consciousness, persistent antegrade amnesia


Dangerous mechanism (For example: ejection from motor vehicle)


Elderly population age >60


Drug or ETOH intoxication or inappropriate mental status


Seizure or focal neurologic deficit


Coagulopathy


Trauma above the level of clavicle


Skull Fractures


Described based upon the following characteristics:


• Open vs. closed


• Depressed vs. nondepressed


• Linear vs. comminuted


Epidural Hematoma


Hematoma between the dura and the skull


Lateral fracture of skull resulting in disruption of middle meningeal artery or nearby vessel


Convex appearance


Presents as lucid interval: Temporary improvement in consciousness followed by deterioration


RADIOLOGY


CT findings (Fig. 12.1)


• Lentiform-shaped hyperdense area immediately deep to the skull, often in the temporal or parietal regions


• Does not cross cranial sutures


• Areas of hypodensity may indicate active hemorrhage


FIGURE 12.1


A. Epidural hematoma


B. Frontal lobe


C. Temporal lobe


D. Cerebellum


E. Pons


F. Petrous pyramid



Subdural Hematoma


Hematoma between the dura and the cortex


Due to tearing of bridging veins


Concave appearance


RADIOLOGY


Subdural Hematoma


CT findings (Fig. 12.2)


• Usually seen as hyperdense fluid layering over the cerebral convexities or along the falx cerebri which appears thickened


• If acute, the blood will be hyperdense, but if chronic, the blood will be mixed in density


• Blood decreases in density over time with a similar density to CSF after a few weeks to months


FIGURE 12.2 A–C


FIGURE 12.2 A


A. Subdural hematoma


B. Right-to-left midline shift


C. Lateral ventricles


D. Falx cerebri


E. Scalp hematoma



FIGURE 12.2 B


A. Subdural hematoma


B. Right-to-left midline shift


C. Lateral ventricles


D. Falx cerebri


E. Tentorium cerebelli


F. Cerebellum


G. Scalp hematoma



FIGURE 12.2 C


A. Subdural hematoma


B. Occipital lobe


C. Scalp hematoma


D. Tentorium cerebelli


E. Cerebellum



Subdural Hematoma with Diffuse Cerebral Edema


CT findings (Fig. 12.3)


• Effacement of cerebral sulci, as well as the suprasellar and quadrigeminal plate cisterns


• Compression of ventricular systems may be seen


• Edema causes diffuse decreased attenuation of the brain parenchyma with loss of the gray–white junction


FIGURE 12.3


A. Subdural hematoma


B. Narrowed ventricles from edema


C. Parietal bone fracture


D. Loss of sulci


E. Diffuse scalp hematoma



Subarachnoid Hemorrhage


Bleeding into the subarachnoid space (area between the pia mater and the arachnoid membrane)


Disruption of vessels feeding the cortex


Signifies traumatic brain injury


RADIOLOGY


Subarachnoid Hemorrhage (SAH)


CT findings (Fig. 12.4)


• Hyperdense fluid that follows the sulci and gyri of the cerebrum (unlike subdural hemorrhages)


• Blood within the ventricles, cisterns, and spinal canal can also be seen


MRI findings


• Dark, “blooming” artifact is seen with blood on T2* GRE


• Failure to suppress the CSF on FLAIR sequences may indicate blood (which appears as bright fluid around the cerebral sulci and hyri)


• If chronic SAH, a thin layer of T2 hypointense signal outlining the leptomeninges, especially in the basal cisterns can be seen


FIGURE 12.4 A–C


FIGURE 12.4 A


A. Subarachnoid hemorrhage


B. Falx cerebri


C. Lateral ventricles



FIGURE 12.4 B


A. Subarachnoid hemorrhage


B. Falx cerebri


C. Anterior horn of lateral ventricles


D. Temporal horn of lateral ventricles


E. Third ventricle


F. Gyrus


G. Sulcus


H. Tentorium cerebelli


I. Pons



FIGURE 12.4 C


A. Subarachnoid hemorrhage


B. Lateral ventricle


C. Occipital lobe


D. Cerebellum


E. Pons


F. Parietal lobe


G. Pituitary



Brain Herniation


CT findings (Fig. 12.5)


• Subfalcine herniation is the most common form of brain herniation


• Cingulate gyrus is displaced across the midline under the falx cerebri


• Compression of adjacent lateral ventricle may be seen


• Patients are at risk of anterior cerebral artery infarction in the distribution of the callosomarginal branch, where it is susceptible to compression against the falx cerebri


FIGURE 12.5 A–C


FIGURE 12.5 A


A. Subfalcine herniation


B. Left-to-right midline shift


C. Lateral ventricles


D. Posterior horn of lateral ventricles



FIGURE 12.5 B


A. Subfalcine herniation


B. Subdural hematoma


C. Left-to-right midline shift


D. Lateral ventricles


E. Anterior horn of lateral ventricles


F. Subarachnoid hemorrhage



FIGURE 12.5 C


A. Tonsillar herniation


B. Transtentorial herniation


C. Cerebellum


D. Occipital lobe


E. Tentorium cerebelli


F. Lateral ventricle


G. Parietal lobe


H. Frontal lobe


I. Scalp hematoma



Intraparenchymal Hemorrhage


Bleeding into the brain parenchyma


Ranges from small contusions to large hematoma


Diffuse Axonal Injury


Severe rotational forces lead to shear injury to white matter pathways


Not directly seen on CT imaging but suggested by


• punctate hemorrhages


• loss of the gray/white matter differentiation


Spinal Injuries


Overview (Illustration 1)


Anterior column: Anterior half of the vertebral body and disc, anterior longitudinal ligament


Middle column: Posterior half of the vertebral body and disc, posterior longitudinal ligament


Posterior column: Pedicles, lamina, ligamentum flavum, transverse process, spinous process, articular process, supraspinous and interspinous ligaments, joint capsules


Instability:


• Fracture that disrupts two of the three columns


• Compression with reduction of more than 50% of vertebral height


• More than 2.5 mm sagittal plane displacement of the vertebral body


• Angulation of more than 20 degrees in the sagittal plane


Illustration 1


Spine anatomy



Cervical Spine Injuries (C-spine)


One-third occur at level of C2


One-half occur at level of C6–C7


NEXUS (National Emergency X-Radiography Utilization Study) criteria—C-spine is determined to be stable if:


C-spine injuries


GCS 15 (no neurologic deficit)


No intoxication


No painful distracting injury


No focal neurologic deficit


No posterior midline tenderness


RADIOLOGY


Plain film findings


• Trauma series includes AP, lateral, and open mouth (odontoid views)


• Malalignment of any element within the cervical spine (vertebral bodies, facet joints, spinous processes, etc.)


• May see increased interspinous distance or widening of the intervertebral disc spaces


• Abnormal motion of the vertebrae with neck flexion and extension views indicate ligamentous injury


CT findings


• More sensitive examination for cervical spine injuries (Fig 12.6 A-D)


• Provides more detail of the extent of injury seen on plain film


MRI findings


• More sensitive examination for soft tissue injuries such as ligament tears


• Examination of choice to evaluate for spinal cord injuries


• Can detect epidural/subdural hematomas within the spinal canal


FIGURE 12.6 AD



FIGURE 12.6 A



FIGURE 12.6 B


FIGURE 12.6 C


A. Vertebral body



FIGURE 12.6 D



Flexion Injuries


Simple wedge (Illustration 2)


• Anterior body wedging


• Decreased vertebral body height, increased density on imaging


• Stable


ILLUSTRATION 2


Simple wedge fracture



Flexion teardrop (Illustration 3)


• Flexion with vertical axial compression


• Fracture of anteroinferior aspect of vertebral body with displacement


• Involves disruption of all three columns and associated with cord injury


• Unstable


ILLUSTRATION 3


Flexion teardrop



Anterior subluxation (Illustration 4)


• Rupture of posterior ligamentous structures


• Widening of interspinous space seen on lateral view


• Stable, but rarely associated with neurologic deficit, most are treated as unstable


ILLUSTRATION 4


Anterior subluxation



Bilateral facet dislocation (Illustration 5)


• Anterior subluxation with displacement of more than half of AP diameter, resulting in a “locked facet”


• Associated with disk rupture


• Unstable


ILLUSTRATION 5


Bilateral facet dislocation



Clay-shoveler (Illustration 6)


• Abrupt flexion with neck contraction


• Oblique fracture at base of spinous process, usually low C-spine


• Stable


ILLUSTRATION 6


Clay shoveler



Flexion–rotation (Illustration 7)


• Unilateral facet dislocation


• Inferior facet of upper vertebra passes superior and anterior to superior facet of lower vertebra


• Disruption of posterior ligament


• Anterior displacement < one-half of AP diameter of body on lateral view


• Stable


ILLUSTRATION 7


Flexion–rotation



Rotatory atlantoaxial dislocation (Illustration 8)


• Specific unilateral facet dislocation


• Asymmetry of C1 with respect to dens


• Unstable


ILLUSTRATION 8


Rotatory atlantoaxial dislocation



Extension Injuries


Hangman fracture (Illustration 9)


• Traumatic spondylolisthesis of C2


• Bilateral fractures through pedicles of C2


• Rarely associated with spinal cord injury


• Unstable


ILLUSTRATION 9


Hangman fracture



Extension teardrop (Illustration 10)


• Anterior longitudinal ligament pulls away inferior aspect of vertebra


• Hyperextension avulsion injury


• Common in diving accidents


• Unstable in extension (no traction)


• Stable in flexion


ILLUSTRATION 10


Extension teardrop



Jefferson fracture (Illustration 11)


• Burst fracture ring of C1


• Fracture of anterior and posterior arches


• Unstable


ILLUSTRATION 11


Jefferson fracture



Thoracic and Lumbar Spine Injuries


RADIOLOGY


FIGURE 12.7 A,B



FIGURE 12.7 A



FIGURE 12.7 B


Flexion/Compression


Wedge and compression fractures (Illustration 12)


• Anterior column only—stable


• Anterior and posterior column—potentially unstable


• Three column—unstable with possible cord, nerve root, or vascular injury


ILLUSTRATION 12


Wedge and compression fracture



Axial compression


• Burst fracture (Illustration 13)


• Anterior and middle columns compressed leading to loss of vertebral height


Five subtypes:


1. Fracture of both endplates


2. Fracture of superior endplate (most common)


3. Fracture of inferior endplate


4. Burst rotation


5. Burst lateral flexion fracture


Stable burst fractures do not involve posterior column


Unstable burst fractures involve posterior column


Imaging required to evaluate canal impingement


ILLUSTRATION 13


Burst fracture


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Dec 27, 2016 | Posted by in ULTRASONOGRAPHY | Comments Off on Trauma

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