Availability and Quality of Computed Tomography and Magnetic Resonance Imaging Equipment in U.S. Emergency Departments

Abstract

Objectives: The objective was to determine the availability and quality of computed tomography (CT) and magnetic resonance imaging (MRI) equipment in U.S. emergency departments (EDs). The authors hypothesized that smaller, rural EDs have less availability and lower-quality equipment.Methods: This was a random selection of 262 (5%) U.S. EDs from the 2005 National Emergency Department Inventories (NEDI)-USA (http://www.emnet-usa.org/). The authors telephoned radiology technicians about the presence of CT and MRI equipment, availability for ED imaging, and number of slices for the available CT scanners. The analysis was stratified by site characteristics.Results: The authors collected data from 260 institutions (99% response). In this random sample of EDs, the median annual patient visit volume was 19,872 (interquartile range = 6,788 to 35,757), 28% (95% confidence interval [CI] = 22% to 33%) were rural, and 27% (95% CI = 21% to 32%) participated in the Critical Access Hospital program. CT scanners were present in 249 (96%) institutions, and of these, 235 (94%) had 24 ⁄ 7 access for ED patients. CT scanner resolution varied: 28% had 1-4 slice, 33% had 5-16 slice, and 39% had a more than 16 slice. On-site MRI was available for 171 (66%) institutions, and mobile MRI for 53 (20%). Smaller, rural, and critical access hospitals had lower CT and MRI availability and less access to higher-resolution CT scanners.Conclusions: Although access to CT imaging was high (>90%), CT resolution and access to MRI were variable. Based on observed differences, the availability and quality of imaging equipment may vary by ED size and location.ACADEMIC EMERGENCY MEDICINE 2008; 15:780-783 ª

An Updated Definition of Stroke for the 21st Century

“…[45][46][47][48] Therefore, within the first 12 hours of an acute stroke, a tissue-based diagnosis of CNS infarction is not possible with the use of routine noncontrast head CT alone but could be if MRI were widely used. Because noncontrast head CT remains the most commonly used imaging modality in the acute setting, 49 a patient may have a clear clinical vascular syndrome supporting a diagnosis of CNS infarction but not meet a tissue-based definition of CNS infarction if only CT is used. In addition, the type of imaging modality selected may determine if a tissue-based diagnosis of CNS infarction is made based on the location of the stroke.…”

Diagnostic Performance of Ultrafast Brain MRI for Evaluation of Abusive Head Trauma

“…7 A noncontrast head CT (nHCT) is usually the initial imaging study in suspected AHT due to high sensitivity for detection of acute hemorrhage and fracture, a high level of accessibility from the emergency department, and can be performed quickly and safely without the need for special monitoring equipment. 8,9 CT imaging disadvantages include ionizing radiation, particularly in children, and the reduced sensitivity in detecting microhemorrhages, axonal injury, and acute ischemia compared to MRI. 10 MRI is frequently performed in AHT and adds additional information in 25% of all children with abnormalities on the initial CT scan.…”

Therapeutic Strategies in Acute Intracerebral Hemorrhage

“…CT scanners are rapidly and commonly available in emergency departments in the United States [40] and highly sensitive in detecting ICH.…”

“…In addition, CT venography is very accurate in diagnosing venous sinus thrombosis, another secondary cause of ICH [42]. As CT scanners are widely available [40], CT angiography is often used as an initial diagnostic modality in many centers, and may not meaningfully raise the risk of nephropathy following ICH [43].…”