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Glioma
- most common primary malignant brain tumor
- consists of glial cells (supporting connective tissue in the CNS) that still have ability to multiply
- Radiographic Appearance: MRI; CT (non-enhanced) shows a single heterogeneous mass (isodense to hypodense); CT (contrast enhanced) shows a homogeneous lesion with irregular ring of enhancement
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Meningioma
- benign tumor that arises from arachnoid lining cells and is attached to the dura
- Radiographic Appearance: MRI; CT (head) shows rounded, sharply delineated, hyperdense tumor abutting a dural surface; CT (spine) myelogram demonstrates location of mass as a filling defect
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Epidural Hematoma
- result of trauma, acute arterial bleeding usually caused by laceration of the medial meningeal artery of its branches
- acute neurological symptoms and emergency surgery to relieve intracranial pressure
- Radiographic Appearance: CT - biconvex peripheral high-density lesion, showing midline shift
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Subdural Hematoma
- venous bleeding, most commonly from ruptured veins between the dura and meninges
- slower bleed (than arterial) with gradual neurologic deficits
- Radiographic Appearance: CT: acute - crescent-shaped peripheral high-density lesion; chronic - isodense lesion
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Contusion
- injury to brain tissue (commonly frontal and anterior temporal) caused by movement of brain within skull after blunt trauma
- Radiographic Appearance: CT - low-density areas that usually enhance (after contrast injection) for several weeks
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Linear Skull Fracture
sharp lucent line that is often irregular or jagged
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Tripod Fracture
fracture of the zygomatic arch and the orbital floor or rim combined with separation of the zygomaticofrontal suture
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Basilar Skull Fracture
suggestive finding for fracture may be air-fluid level in the sphenoid sinus seen on lateral projection of skull using horizontal central ray
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Intracerebral Hematoma
- traumatic hemorrhage into the brain parenchyma resulting from shearing forces to intraparenchymal arteries usually at the junction of the gray and white matter
- Radiographic Appearance: CT - will-circumscrided, homogeneous, high-density region surrounded by low-density regions of edema
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Intraparenchymal Hemorrhage
- principle cause of hemorrhage is hypertensive vascular disease
- can also be a congenital berry aneurysm or an arteriovenous malformation
- Radiographic Appearance: CT - new hematoma appears as a homogeneously dense, well-defined, round or oval lesion, becoming isodense over time; 6 month-old hematoma appears as a well-defined, low-density lesion
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Subarachnoid Hemorrhage (Trauma)
- injury to surface veins, cerebral parenchyma, or cortical arteries can produce bleeding into the ventricular system
- Radiographic Appearance: CT - increased density within the basilar cisterns, cerebral fissures, and sulci
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Subarachnoid Appearance (Vascular)
- major cause of hemorrhage is rupture of berry aneurysm
- most common locations are origins of the posterior cerebral and anterior communicating arteries and the trifurcation of the middle cerebral artery
- Radiographic Appearance: CT - noncontrast scan initially shows high attenuation of blood in the subarachnoid space
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Cerebrovascular Accident
- cerebrovascular disease refers to any process that is caused by an abnormality of the blood vessels or blood supply to the brain
- can be divided into three categories: completed stroke, TIA's and intracranial hemorrhage
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Stroke
- sudden loss of brain function caused by the interruption of flow of blood to the brain (ischemic stroke approx 80%) or the rupture of blood vessels in the brain (hemorrhagic stroke)
- interruption of blood flow or the rupture of blood vessels causes neurons in the affected area to die (cerebral infarct) and effects of a stroke depend on where the brain was injured, as well as how much damage occured
- Radiographic Appearance: the purpose of immediate CT evaluation in the acute stroke patient is not to confirm the diagnosis of a stroke but to exclude intracranial hemorrhage before treatment; CT - (initially) a triangular or wedge-shaped hypodensity on noncontrast scan with mass effect seen 7-10 days after onset
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Transient Ischemic Attack
- caused by temporary interruption of blood flow to the brain
- symptoms are similar to an ischemic stroke except they are temporary
- an important warning sign for increased risk of stroke
- Radiographic Appearance: ultrasound of MRI
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Normal Aging
- gradual loss of neurons results in enlargement of the ventricular system and sulci
- Radiographic Appearance: CT - low density periventricular regions
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Alzheimer's Disease
- diffuse form of progressive cerebral atrophy that develops at an earlier age than the senile period (presenile dementia)
- Radiographic Appearance: CT - cerebral atrophy with enlarged ventricles and prominent cortical sulci
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Huntington's Disease
- atrophy of the caudate nucleus and putamen
- inherited condition that predominantly involves men and appears as dementia and typical choreiform movements (involuntary movements that are rapid jerky, and continuous)
- Radiographic Appearance: CT - focal ventricular dilatation; loss of normal shape of frontal horns
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Parkinson's Disease
- major degenerative changes in nerve cells occur in the basal ganglia
- enzyme defect that results in an inadequate production of the neuronal transmitter substance dopamine
- disease is gradually progressive
- characterized by stooped posture, stiffness and slowness of movement, fixed facial expression, and involuntary rhythmic tremor of limbs that disappears with voluntary movement
- Radiographic Appearance: CT - appears similar to that of normal aging process
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Hydrocephalus (Hydrocephaly)
- dilatation of the ventricular system usually associated with increase intracranial pressure
- usually due to an obstruction of flow of the spinal fluid causing cranium enlargement
- insertion of a shunt between dilated ventricles and the heart or peritoneal cavity to decrease intracranial pressure and ventricular size
- Radiographic Appearance: CT - demonstrates ventricular dilatation and used for monitoring
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