Other advantages of CT over MRI scan are ability to detect bony fractures, vascular injury, and cerebrospinal fluid (CSF) leak. It also does not need to screen for MRI safety of implants/foreign body especially for penetrating or blast injuries.However, MRI has higher sensitivity than CT scan for the detection of epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, nonhemorrhagic cortical contusions, hemorrhagic parenchymal contusions, brainstem injuries, and white matter axonal injuries. If CT scan shows normal findings, but the subject has persistent neurological symptoms, MRI is also indicated. However, MRI safety concerns on metallic foreign bodies, limited availability, longer imaging time, high sensitivity to motion, and higher cost limits the usefulness of MRI.Swirl sign on CT scan (areas of low densities with surrounding areas of high densities) is indicative of active intracranial bleeding, high chance of death within one month, and poor subjects function in three months if the subject is still alive.When ICP is increased the heart rate may be decreased. Traumatic
Types of intracranial hemorrhage are roughly grouped into intra-axial and extra-axial. Intra-axial hemorrhage is bleeding within the brain itself, or cerebral hemorrhage. This category includes intraparenchymal hemorrhage, or bleeding within the brain tissue, and intraventricular hemorrhage, bleeding within the brains ventricles (particularly of premature infants). Intra-axial hemorrhages are more dangerous and harder to treat than extra-axial bleeds. Hemorrhagic parenchymal contusions and cerebral microhemorrhages are examples of traumatic intra-axial bleeds.Extra-axial hemorrhage, bleeding that occurs within the skull but outside of the brain tissue, falls into three subtypes: epidural hematoma, subdural hematoma, and subarachnoid hemorrhage.
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