Utility of Emergency Cranial Computed Tomography in Patients Without Trauma

Abstract

Objectives: The objectives of this study were to determine, in patients admitted to the hospital from the emergency department (ED) without evidence of trauma, 1) the prevalence of clinically important abnormalities on cranial computed tomography (CCT) and 2) the frequency of emergent therapeutic interventions required because of these abnormalities. Methods:The authors retrospectively reviewed the records of all patients from 2007 between the ages of 18 and 89 years who had CCT as part of their ED evaluations prior to hospitalization. Patients with any indication of trauma were excluded, as were those who had a lumbar puncture (LP). Chief complaint, results of the ED neurologic examination, tomogram findings, and whether patients had emergent interventions were recorded. Patients presenting with altered mental status (AMS) were analyzed separately.Results: Of the 766 patients meeting inclusion criteria, 83 (11%) had focal neurologic findings, and 61 (8%) had clinically important abnormalities on computed tomography. Emergent interventions occurred in only 12 (1.6%), 11 (92%) of whom had focal neurologic findings. In the subgroup of 287 patients with AMS as their presenting problem, 14 (4.9%) had focal findings, six (2%) had clinically important abnormalities on tomography, and only two (0.7%) required emergent interventions, both of whom had focal findings. Patients presenting with AMS were less likely to have positive findings on tomography (odds ratio [OR] = 0.16, 95% confidence interval [CI] = 0.07 to 0.39). Patients presenting with motor weakness or speech abnormalities, or who were unresponsive, were more likely to have positive findings on tomography (OR = 4.7, 95% CI = 2.6 to 8.6; OR = 4.4, 95% CI = 1.5 to 2.7; and OR = 3.3, 95% CI = 1.6 to 7.1, respectively). Conclusions:Of patients without evidence of trauma who receive CCT in the ED, the prevalence of focal neurologic findings and clinically important abnormalities on tomography is low, the need for emergent intervention is very low, and the large majority of patients requiring emergent intervention have focal findings. The yield of CCT was lower for patients presenting with AMS, and higher for patients presenting with motor weakness or speech abnormalities, and for those who were unresponsive.

ACR Appropriateness Criteria® Acute Mental Status Change, Delirium, and New Onset Psychosis

“…However, a noncontrast head CT is the first-line neuroimaging test of choice in this setting and can be performed safely and rapidly in all patients [2]. Yield of acute contributory findings on CT ranged from 2% to 45% based on trial design and inclusion or exclusion criteria [2,[26][27][28][29][30]. Subgroup analysis of patients with AMS and no focal deficits in one study noted acute changes on imaging in 7.4% of patients [27].…”

“…Subgroup analysis of patients with AMS and no focal deficits in one study noted acute changes on imaging in 7.4% of patients [27]. Risk factors associated with intracranial findings included history of trauma or falls, hypertension, anticoagulant use, headache, nausea or vomiting, older age, impaired consciousness or unresponsiveness, neurologic deficit, and history of malignancy [2,[26][27][28][29][30]. However, different studies found variable levels of significance of these associations.…”

“…For patients with AMS not responding to initial management of the suspected underlying medical cause, neuroimaging with a noncontrast head CT is usually appropriate to evaluate for a possible neurological source of their symptoms, including acute ICH, infarct, brain mass, hydrocephalus, or mass effect. The diagnostic yield may be low in the absence of a focal neurological deficit or signs of trauma [2,17,27,29,36]. No prospectively validated clinical rule or scoring system is available to help define which of these patients benefit the most from imaging.…”

“…Therefore, determining the clinical need and value of brain imaging in this scenario relies on the evaluating clinician's judgement. Unresponsive patients may have higher rates of acute findings on CT [29].…”

“…Contrast-enhanced CT examinations are usually not performed as a first-line test in this setting but may be considered as a second-line test to assess abnormalities found on the screening head CT and for patients unable or unwilling to have MRI [31]. Evidence guiding appropriate imaging recommendations in this variant is limited, as most studies in the literature search sampled undifferentiated patient populations with a broad range of risk factors and are not directly applicable to this variant [2,26,[28][29][30].…”