Planning 6- and 24-hour Computed Tomography for Conservatively Managed Intracranial Hemorrhages: A Quality Improvement Study

Introduction: Computed tomography (CT) scans are essential to monitor the progression of intracranial hemorrhages, but expose patients to unnecessary radiation and increase hospital burden and patient expenses. Current protocols include follow-up imaging at 6 and 24 hours. This study optimizes the requirement of both the 6- and 24-hour scans.

Methods: We conducted a retrospective review of electronic medical records from identifying adult patients who underwent both 6- and 24-hour CT scans. CT imaging indications (routine follow-up or neurological deterioration) were documented alongside neurological and radiological findings at 6 and 24 hours. The primary analyses evaluated the odds of detecting new or worsening lesions on the 24-hour CT based on a worsening radiological picture at 6 hours. Secondary analyses compared these odds for intra-axial versus extra-axial hemorrhages.

Results: In the cohort of 135 lesions, the odds of detecting a new or worsening hemorrhage on the 24-hour CT scan were influenced by the radiological findings on the 6-hour scan. The likelihood of hemorrhage detection was significantly higher in patients with an abnormal 6-hour scan compared to those with a normal scan (25.0% vs 10.3%, p-0.041; OR: 2.909 [95% CI: 1.009- 8.386]). In the subgroup of intra-axial hemorrhages (n=87), the odds of detecting a hemorrhage on the 24-hour scan did not differ significantly between those with an abnormal versus normal 6-hour scan (21.4% vs 13.7%, p-0.432; OR: 1.466). For extra-axial hemorrhages (n=41), the likelihood of detecting a hemorrhage on the 24-hour scan was substantially higher in patients with an abnormal 6-hour scan compared to those with a normal 6-hour scan (33.3% vs 3.2%, p-0.030; OR: 15.0 [95% CI: 1.325-169.871).

Conclusion : For extra-axial hemorrhages, a 24-hour CT is warranted only if the 6-hour CT shows radiological change. In contrast, both 6-hour and 24-hour CT scans continue to be indicated for intra-axial hemorrhages regardless of radiological or neurological changes.