The Choosing Wisely Campaign lists non-contrast CT of the head as one of their low-value procedures for low-risk patients presenting with syncope. However, despite these recommendations, these authors voice concerns up to two-thirds of patients still undergo advanced imaging.
In this systematic review looking at both practice patterns and yield, the authors identify 17 studies of both hospitalized and Emergency Department patients addressing this topic. Pooling together 1,669 ED patients, 55% underwent CT with a yield of 3.8%. Pooling 1,289 hospitalized patients, CTs were performed 45% of the time with a yield of 1.2%. Considering the general morbidity and mortality associated with intracranial conditions, these are not fantastic yield numbers, but are not entirely unreasonable.
There is a bit of trouble with these numbers, however: even though their systematic review went up to 2017, most of the included studies were published before 2011. Even their citation of “two-thirds receiving head CTs” was published in 2009, well before the 2014 Choosing Wisely statement. Then, the bulk of the included studies were retrospective, blurring the reliability of their inclusion and outcomes measurement.
I think these data probably effectively illustrate the rarity of serious outcomes in syncope, but provide little insight into the current scope of the problem with respect to overuse. An intracranial process or intracranial injury associated with syncope ought to be considered in each case, but better data describing features predictive of underlying intracranial injury is needed to better separate high-risk from low-risk.
“The Yield of Computed Tomography of the Head Among Patients Presenting With Syncope: A Systematic Review”
https://www.ncbi.nlm.nih.gov/pubmed/31006937