Radio Flashcards
assessment of skull trauma( Radiography)
Xray only in :
lateral projection
-unless there is clinical evidence to suggest that lesion may show in other views
MRI
ADVANTAGES
Lack of ionizing radiation
Very good soft tissue contrast
Excellent visualization of vascular structures even without administration of contrast agents
DISADVANTAGES
Longer imaging times
ncreased artifacts due to patient motion
Increased cost
Patient has implanted
metallic foreign body
CT
ADVANTAGES
Rapid, short imaging times
Widespread availability
Optimal detection ofcalcification and hemorrhage
Good resolution of bone detail
DISADVANTAGES
Ionized radiation
CT
-Primary radiological modality of evaluating acute head injury
-very sensitive for acute hemorrhage and cerebral edema
-Best modality for assessing fractures of skull base, calvarium and facial bones with 3D reconstruction images
-Assessment of spinal fractures and narrowing of spinal canal
-Detection of calcifications, skull erosion, destruction and hyperostosis
MRI
Different MRI pulse sequences to characterize brain parenchymal pathologies
- detect acute brain ischemia as early as within first few minutes of onset of symptoms
-Assessment of disc herniation and spinal canal stenosis better than CT
- brain tumors MRI has best sensitivity in assessment of size, extent, and effect on normal brain and spinal cord
-Ventricular system best assessed on MRI Most sensitive for detecting demyelinating multiple myeloma plaques
Abnormal intracranial calcification :
Idiopathic basal ganglia calcification
Neoplasm’s
Vascular
Infections
Metabolic
Chronic intracranial hematomas
dystrophic and metabolic ( hyperparathyroidism )
CT of ischemia?
Acute = iso-dense
Sub acute = hypo-dense
Chronic = more hypo-dense
Intracranial haemorrhages etiology :
Hypertenstion
Trauma
Vascular malformation-AVM
Aneurysm
Tumor
Coagulopathy
Vasculitis
Types of Intracranial haemorrhages
Epidural (Trauma)
Subdural (Trauma)
Subarachnoid (Trauma, Aneurysms)
Intraparencymal (Hypertension)
Intraventricular
is the most effective tool in ICH diagnosis.
is excellent for imaging blood.
CT scan
Hemorrhage in CT appearance :
Acute Hemorrhage = hyper-dense.
Sub-acute hag = iso-dense.
Chronic hag = hypo-dense.
Follows inner layer of dura
Tendency for crescentic shapes
More mass effect than expected for their size
Source of heg: cortical vein:
Subdural
Follows outer layer of dura (periosteum)
Tendency for lentiform shapes
Source of heg:
skull fracture with arterial or sinus laceration
Epidural heg
Arteriography:
No longer used for diagnosis of cerebral lesions
But still
used for definitive diagnosis of most vascular lesions
Minimally invasive techniques MRA and CT angiography nowadays preferred over direct arteriography
Useful in neonates and infants in case of hydrocephalus but not in older children and adults, It requires a window of an open fontanelle to image the brain, can be used per operatively to assist neurosurgeon in defining the tumor extent
Ultrasound
