A nurse is caring for a client who has a subarachnoid hemorrhage and asks why they are having a CT angiography. Which of the following should the nurse understand about CT angiography?

A) "Damage occurs from the penetrating object shattering the skull and causing an infection." While penetrating traumatic brain injuries can lead to skull fractures and subsequent infections, the primary mechanism of brain damage in these injuries is related to the direct impact of the penetrating object on brain tissue rather than the shattering of the skull.

B) "Damage to the brain is related to coup and contrecoup injuries." Coup and contrecoup injuries occur when the brain impacts the skull's interior surface due to rapid deceleration or acceleration, commonly seen in closed head injuries such as concussions. Penetrating traumatic brain injuries involve direct penetration of foreign objects into the brain tissue, and coup-contrecoup injuries are not typically associated with these types of injuries.

C) "Damage occurs from the penetrating injury causing leakage of cerebrospinal fluid." While penetrating injuries may result in cerebrospinal fluid leakage, this is not the primary mechanism through which they cause brain damage. Leakage of cerebrospinal fluid is more commonly associated with certain types of head trauma, such as skull fractures, rather than solely penetrating injuries.

D) "Damage to the brain is related to the size, route, and rate of speed of the object entering the brain." This statement is correct. The extent of brain damage in penetrating traumatic brain injuries depends on various factors, including the size, shape, and velocity of the penetrating object, as well as the route it takes through the brain tissue. Larger, faster-moving objects tend to cause more extensive damage, whereas smaller objects or those with slower velocities may cause more localized damage. Therefore, understanding these factors is crucial in assessing and managing patients with penetrating traumatic brain injuries.

A. A CT angiogram will reveal any edema within the brain tissue: CT angiography primarily focuses on visualizing blood vessels and blood flow within the brain. While it may incidentally detect areas of edema, its primary purpose is to assess vascular structures rather than brain tissue changes such as edema.

B. A CT angiogram will reveal any overproduction of cerebrospinal fluid (CSF): CT angiography does not assess cerebrospinal fluid (CSF) production. Its main function is to visualize blood vessels and blood flow within the brain, particularly to detect abnormalities such as aneurysms, arteriovenous malformations, or vasospasm.

C. A CT angiogram will reveal any fractures within the skull or spine: CT angiography primarily focuses on imaging blood vessels and is not the preferred modality for detecting fractures within the skull or spine. CT scans or plain radiography are typically used to assess bony structures for fractures.

D. A CT angiogram will reveal any decreased blood flow related to vasospasm: This statement is correct. CT angiography is a specialized imaging technique that combines computed tomography (CT) scanning with contrast dye to visualize blood vessels and blood flow within the brain. It is commonly used to detect and monitor vasospasm, a potentially serious complication of subarachnoid hemorrhage, where blood vessels in the brain constrict, leading to decreased blood flow. CT angiography allows for the visualization of these changes in blood vessel diameter and blood flow dynamics.