A 74-year-old with right hemiparesis needs a diagnostic study after a fall. Which study should be ordered first?

In the context of a 74-year-old patient with right hemiparesis following a fall, the primary concern is to quickly assess for any potential acute intracranial hemorrhage or other urgent pathological changes. A CT scan of the brain is often the first-line imaging study in these situations due to its speed and effectiveness in detecting conditions such as hemorrhagic stroke, subdural hematomas, or other acute injuries.

CT imaging is particularly beneficial in emergency settings because it is widely available, can be performed rapidly, and provides clear visualization of the brain. If a hemorrhage or significant mass effect is present, immediate intervention may be necessary, and the CT can guide that management efficiently.

Other options such as MRI are more sensitive for certain conditions but take longer to perform and are not typically the initial study in acute scenarios where hemorrhage is suspected. Skull x-rays are not routinely helpful in evaluating brain injuries for this type of presentation. Lumbar puncture, while useful in diagnosing conditions like subarachnoid hemorrhage or meningitis, is contraindicated if there is a high suspicion of increased intracranial pressure, which may be the case in this patient with acute neurological deficits after a fall. Thus, the CT scan is the most appropriate first