There is an increasing public interest regarding exposure to medical radiation. It represents the major exposure source for the population at large. There may be a presumption on the part of medical providers that “what you can’t see can’t hurt you” but this is just not the case.

A number of studies have shown that there is risk association with repeated exposure to xray. This risk is particularly important when dealing with pediatric patients. It’s time to start critically looking at our imaging practices and to start critically thinking about every one that we order.

One common source of repeat radiation is the repetitive CT scans of the head that patients who suffer TBI undergo. Frequently, there is little rhyme or reason to the patter of these scans. Should we repeat in 6 hours? 24 hours? When any lesions finish evolving?

It turns out that there is a reasonable amount of guidance in the brain literature. For the most part, they suggest that patients who are not in an ICU only need a repeat CT if their mental status changes. Any others obtained did not result in any management change. The first 6 papers listed below agree with this.

However, number 7 is interesting. It was published in the Journal of the American College of Surgeons and was a retrospective study of patients seen at a Level I Trauma Center. All patients had a lesion seen on initial scan, and underwent repeat scanning. The authors found that 6% of their patients underwent a surgical or medical “intervention” based on changes on the repeat head CT. What troubled them the most was that 21 of these 51 patients did not have any substantial neurologic change. They conclude that routine repeat head CT is very useful.

It’s not clear why their results are so disparate from the others. It is retrospective, and the authors do not state what the interventions exactly are. Nor do they speculate on why their results are so different from others. Nor do they show any difference in outcomes.

The bottom line: Repeat head CT is probably not needed in patients with mild TBI who are not on anti-coagulants or anti-platelet agents. However, regular mental status checks and GCS measurements must be taken.

References:

1. Is repeated head computed tomography necessary for traumatic intracranial hemorrhage? American Surgeon 2005 Sep;71(9):701-4.
2. Routine repeat head CT for minimal head injury is unnecessary. J Trauma 2006, Mar;60(3):494-9.
3. A prospective evaluation of the value of repeat cranial computed tomography in patients with minimal head injury and an intracranial bleed. J Trauma 2006 Oct;61(4):862-7.
4. Indications for routine repeat head computed tomography (CT) stratified by severity of traumatic brain injury. J Trauma 2007 Jun;62(6):1339-44.
5. The role of early follow-up computed tomography imaging in the management of traumatic brain injury patients with intracranial hemorrhage. J Trauma 2007 Jul;63(1):75-82.
6. Value of repeat cranial computed tomography in pediatric patients sustaining moderate to severe traumatic brain injury. J Trauma 2008 Dec;65(6):1293-7.
7. Schedule repeat CT scanning for traumatic brain injury remains important in assessing head injury progression. J Amer Coll Surgeons 2010 May;210:824-32.