Brain CT is commonly included in health screening packages in Korea. It is relatively inexpensive, quick to perform, and does not require contrast, which makes it easy for screening centers to include as part of a routine package.
However, when I think about its actual value as a screening test, I find it somewhat limited.
A non-contrast brain CT can detect certain findings, such as an old cerebral infarction, but many other abnormalities are not easily identified on CT alone. Even in the case of an old lacunar infarction, it may sometimes be difficult to distinguish it from an enlarged perivascular space on CT. In those situations, MRI, particularly FLAIR imaging, can provide more useful information.
For this reason, if brain imaging is truly desired as part of a health checkup, I would generally prefer brain MRI over brain CT. A normal brain CT does not necessarily mean that a brain MRI would also be normal.
There are, however, a few situations in which CT can provide useful additional information. When brain CT is performed together with brain MRA, CT can show calcified plaques in the distal internal carotid arteries. This can sometimes be helpful when interpreting vascular findings on MRA.
CT may also provide useful information in patients who have previously undergone procedures such as aneurysm coiling or surgical clipping, since radiopaque devices and post-treatment changes can be readily appreciated.
It is also important to distinguish routine health screening from diagnostic imaging performed because of symptoms. Brain CT remains a very useful examination in the appropriate clinical setting. In particular, when acute intracranial hemorrhage is suspected, CT can detect blood quickly and is often more practical than MRI as an initial examination. In patients with acute neurological symptoms or other specific clinical concerns, CT may therefore be entirely appropriate.
My view here applies specifically to the use of brain CT as an elective screening test in otherwise asymptomatic adults.
My take: I generally would not recommend adding a standalone brain CT simply because it is included in a health screening package. If there is a genuine reason to perform brain imaging for screening purposes, I would usually prefer MRI. There are selected situations in which CT provides useful complementary information, but for routine screening alone, I do not think it adds enough value to make it a priority.