Final answer:
The patient is typically not required to give informed consent for a noncontrast brain CT to exclude a subdural hematoma because it is a non-invasive procedure with minimal risk.
Step-by-step explanation:
The patient is not required to give informed consent for a noncontrast brain CT to rule out subdural hematoma. Informed consent is generally required for procedures that are invasive or carry significant risks and for procedures requiring sedation or contrast material. Options B, C, and D, which involve CT-guided abscess drainage, stereotactic biopsy of a cranial tumor, and a CTA chest for pulmonary embolism, respectively, would typically require informed consent due to their invasive nature and increased risks. However, a straightforward diagnostic noncontrast CT scan, such as that to exclude a subdural hematoma (Option A), is a non-invasive procedure with minimal risk, and often does not require formal informed consent beyond the general consent for treatment provided upon admission.