Change in Emergency Department Length of Stay Following Routine Adoption of Dual-Energy Computed Tomography to Differentiate Intracranial Hemorrhage from Calcification

Background and purpose: Dual energy computed tomography (DECT) is an advanced CT technique which has been shown to improve accuracy in distinguishing between intracranial hemorrhage and calcification, which is often challenging on conventional CT and therefore may warrant repeat imaging in the emergency department (ED) to document stability and exclude enlarging intracranial hemorrhage. We hypothesized that implementation of a DECT head protocol with fully automated post processing in the ED would decrease the need for repeat imaging and therefore reduce overall ED length of stay (LOS).

Materials and methods: This is a retrospective study comparing ED length of stay over a one-year period before (7/1/2016-6/30/2017) and after (7/1/2018-6/30/2019) implementing a DECT head protocol, for patients scanned for headache, trauma or fall, who were found to have indeterminate intracranial hyperdensities on conventional images, and were subsequently discharged home from the ER (excluding patients who were admitted, taken to the OR, or left against medical advice). Additional clinical information regarding ED time course and management were also reviewed, including data on time to CT scan, CT report, and if applicable, time to repeat CT head and neurosurgical consultation.

Results: There was no significant difference in patient demographics and CT indications between the pre-DECT and post-DECT cohorts. There was a small but statistically significant difference in mean baseline ED LOS in the initial cohorts of 20 minutes (p=0.002). After the inclusion of only intracranial indeterminate hyperdensities, there was a larger statistically significant difference in ED LOS, with mean pre-DECT LOS of 421 minutes and mean post-DECT LOS of 272 mins, resulting in mean LOS reduction of 149 mins (p=0.003). The increased ED LOS correlated with increased frequency of neurosurgical consultation and repeat CT head for the findings of indeterminate intracranial hyperdensities.

Conclusions: ED LOS was significantly longer in the pre-DECT cohort, which was partly attributable to neurosurgical consultation and repeat CT head performed for indeterminate intracranial hyperdensities.

Abbreviations: DECT＝ Dual Energy CT; ED LOS＝ Emergency department length of stay; NECT = Noncontrast enhanced CT; VNCa= Virtual non-calcium.