This issue has come up in Question 19 from the second paper of 2005. Why would it be a bad idea to scan your neurosurgical patient's head? Well, turns out there are numerous issues, which can be grouped into four major categories. There are logistical problems (getting to the scanner and back in one piece), machine problems (eg. contrast and radiation exposure), interpretation problems (how well can you read the scan is important to the utility of that scan) and concerns regarding relevance (i.e. was the CT really necessary, will it change management?)
Logistical limitations:
Machine limitations:
Interpreter limitations:
Relevance to clinical setting
Lee, Bruce, and Andrew Newberg. "Neuroimaging in traumatic brain imaging." NeuroRx 2.2 (2005): 372-383.
Miller, M. Todd, et al. "Initial head computed tomographic scan characteristics have a linear relationship with initial intracranial pressure after trauma." Journal of Trauma-Injury, Infection, and Critical Care 56.5 (2004): 967-973.