Stroke: interobserver agreement of CT middle cerebral artery hypodensity was reasonable.

Clinical bottom line (level 2b)

  1. In patients with acute ischaemic stroke, overall interobserver agreement of middle cerebral artery territory hypodensity was reasonable ( ? =0.53).
  2. In patients with acute ischaemic stroke overall interobserver agreement for hyperdense middle cerebral artery sign was poor ( ? =0.36).
Marks et al: Stroke 1999; 30: 389-392
Expires June 2003

The study

Setting: multicentre, USA

50 patients (aged ?, ?% male) acute ischaemic stroke

Independent blinded reference standard, applied in all patients from a non-consecutive appropriate spectrum.
Reference standard:
  • 24 hour CT scans evaluated for vascular territories involved. If the middle cerebral artery was involved, this was evaluated as showing <33% or >33% hypodensity at 24 hours. Presence of hyperdense middle cerebral artery sign was also assessed.
Diagnostic test: Baseline CT scans. The degree of involvement of the middle cerebral artery territory was estimated as either <33% or >33%. When no hypodensity was present or if another territory was involved, patients were included in the <33% group. Presence of hyperdense middle cerebral artery sign (HMCAS) was also assessed.

The evidence

  • Overall interobserver agreement of middle cerebral artery territory hypodensity was ? =0.52 (p<0.001).
  • Overall interobserver agreement for hyperdense middle cerebral artery sign was ? =0.36 (p<0.0001).
  • CT scan readers correctly called >33% middle cerebral artery hypodensity involvement with a sensitivity of 60% to 85% and a specificity of 86% to 97%.

Comments

  1. Data was taken from a multicentre trial evaluating intravenous tissue plasminogen activator in early stroke.
  2. CT scans were selected from participating patients to give a representative mix of findings.

Citation

  1. Marks MP, Holmgren EB, Fox AJ, et al: Evaluation of early computed tomography findings in acute ischaemic stroke. Stroke 1999; 30: 389-392
Contributor: Clare Wotton and Musab Hayatli, December 1999
Reviewer:

Clinical Question.
Patient acute ischaemic stroke
Intervention or Exposure CT detection of large brain-tissue volume
Comparison
Outcome exclusion for tissue plasminogen activator therapy