ArticlesMagnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison
Introduction
Magnetic resonance imaging (MRI) is generally thought to be better than computed tomography (CT) for the diagnosis of acute stroke, but this belief has never been substantiated for the full range of patients in whom this diagnosis is suspected. Patients who present to the emergency room with stroke-like symptoms might have cerebrovascular disease (ischaemic or haemorrhagic) or various other non-vascular disorders. The ideal imaging modality for assessment of patients with acute stroke should accurately detect both cerebral ischaemia and intracranial haemorrhage, and discriminate cerebrovascular causes from other causes. CT is the most common imaging modality used to assess patients with suspected stroke. This method is widely available, fast, easy, and less expensive than MRI. However, although CT is sensitive to acute intracranial haemorrhage, it is not sensitive to acute ischaemic stroke. Studies suggest that CT is insufficiently sensitive for the diagnosis of acute ischaemia, is subject to substantial inter-rater variability in interpretation, and might not be better than MRI for detection of acute intracranial haemorrhage.1, 2, 3, 4
MRI offers advantages for the assessment of acute stroke. Changes of acute ischaemic injury are detectable sooner with MRI than with CT, especially with diffusion-weighted imaging, and ischaemic stroke diagnosis with MRI has greater interobserver and intraobserver reliability than CT, even in readers with little experience.5, 6, 7, 8 Historical concerns that MRI is not sufficiently sensitive to detect acute intracranial haemorrhage in the earliest hours from onset have been addressed by studies that show gradient-echo MRI is as accurate as CT in patients with focal stroke symptoms within 6 h of symptom onset.1, 3 However, the relative diagnostic yield of MRI and CT for routine emergency assessment of possible stroke, irrespective of time from onset, severity of symptoms, or ultimate diagnosis (cerebrovascular or otherwise), had not been investigated. We aimed to prospectively compare CT and MRI for the detection of acute stroke in the full range of patients who present for emergency assessment of stroke-like symptoms.
Section snippets
Study participants and clinical diagnosis
This study was a single-site, prospective comparison of CT and MRI for the assessment of acute stroke. It took place from Sept, 30, 2000, to Feb, 25, 2002, at Suburban Hospital, a community hospital in Bethesda, Maryland, USA, in accordance with the institutional review boards of both the hospital and the National Institute of Neurological Disorders and Stroke. A consecutive series of patients referred to the hospital's stroke team because of suspicion of acute stroke were eligible,
Results
Over 18 months, 450 patients were screened and 94 were excluded—49 because of MRI contraindications (ie, electronic implants, severe patient agitation or claustrophobia, or medical instability); 34 because CT was not obtained because of failure to follow protocol or because treatment was initiated immediately after MRI; and 11 because CT was uninterpretable (ie, severe patient movement or failure to save scans). All MRIs were judged adequate for the panel of readers to make an interpretation of
Discussion
We report that MRI is more effective than CT for the diagnosis of acute stroke in a typical patient sample. Our sample was representative of the range of patients who are likely to present with a clinical suspicion of acute stroke, including patients who ultimately proved to have a different diagnosis. Therefore, our results are directly applicable to clinical practice.
The earliest comparisons of MRI to CT in the diagnosis of acute stroke, from the early 1990s, before clinical
References (29)
- et al.
The Recognition of Stroke in the Emergency Room (ROSIER) scale: development and validation of a stroke recognition instrument
Lancet Neurol
(2005) - et al.
A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack
Lancet
(2005) - et al.
Stroke magnetic resonance imaging is accurate in hyperacute intracerebral hemorrhage: a multicenter study on the validity of stroke imaging
Stroke
(2004) - et al.
Agreement and variability in the interpretation of early CT changes in stroke patients qualifying for intravenous rtPA therapy
Stroke
(1999) - et al.
Comparison of MRI and CT for detection of acute intracerebral hemorrhage
JAMA
(2004) - et al.
Early signs of brain infarction at CT: observer reliability and outcome after thrombolytic treatment—systematic review
Radiology
(2005) - et al.
Acute human stroke studied by whole brain echo planar diffusion-weighted magnetic resonance imaging
Ann Neurol
(1995) - et al.
Magnetic resonance versus computed tomographic imaging in acute stroke
Stroke
(1995) - et al.
Diagnosis of acute cerebral infarction: comparison of CT and MR imaging
AJNR Am J Neuroradiol
(1991) - et al.
CT and diffusion-weighted MR imaging in randomized order: diffusion-weighted imaging results in higher accuracy and lower interrater variability in the diagnosis of hyperacute ischemic stroke
Stroke
(2002)
Fast magnetic resonance diffusion-weighted imaging of acute human stroke
Neurology
Diffusion-weighted MR imaging: diagnostic accuracy in patients imaged within 6 hours of stroke symptom onset
Radiology
Diffusion MRI in ischemic stroke compared to pathologically verified infarction
Neurology
Comparison of diffusion-weighted MRI and CT in acute stroke
Neurology
Cited by (962)
Identification of diagnostic signatures for ischemic stroke by machine learning algorithm
2024, Journal of Stroke and Cerebrovascular DiseasesmcTFI QSM MRI ABC/2 intracranial hemorrhage to noncontrast head CT volume measurement equivalence
2024, Journal of the Neurological SciencesImmuno-MRI for Stroke Diagnosis and Prognosis
2024, NeurosciencePosterior circulation cerebral infarction: A review of clinical, imaging features, management, and outcomes
2023, European Journal of Radiology OpenUltrafast Brain MRI Protocol at 1.5 T Using Deep Learning and Multi-shot EPI
2023, Academic Radiology