Stroke: MR angiography helped rule significant carotid artery stenosis in or out

Clinical bottom line (level 1b)

  1. 12% of carotid arteries under investigation for stenosis had > 70% stenosis.
  2. Normal maximum intensity projection images on MR angiography made significant carotid stenosis much less likely.
  3. Abnormal artery size on MR angiography source images made significant carotid artery stenosis more likely.
Hudson et al: Radiology 2001; 218 : 138-143
Expires January 2003

The study

Setting:

50 patients (aged 46 to 84; mean 68, 62% male) with suspected carotid occlusive disease scheduled to undergo conventional angiography

Excluded if
  • failed to complete either study


Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:
  • conventional angiography: 70% stenosis or more (NASCET criteria)
Diagnostic test: elliptic centric contrast-enhanced MR angiography
  • 3 radiologists reviewed the scans independently.

The evidence

pre-test probability of carotid stenosis > 70%: 95%, (12% CI: 5.8% to 19%)

diagnostic test carotid stenosis > 70% carotid stenosis 70% or less LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
MR angiography: maximum intensity projection 11 13 6.1
(3.6 to 10) 		46% 0.098
(0.015 to 0.64) 		1.4%
MR angiography: source image 10 3 24
(7.6 to 75) 		77% 0.17
(0.048 to 0.61) 		2.4%
total 12 86

K interobserver source images: 0.96
K interobserver maximum intensity projection images: 0.98

Citation

  1. Hudson J, Fain SB, Wald JT, et al: carotid artery: elliptic centric contrast-enhanced MR angiography compared with conventional angiography. Radiology 2001; 218 : 138-143
Search Terms:
Contributor: , January 1999
Reviewer:

Clinical Question.
Patient suspected carotid artery stenosis
Intervention or Exposure MR angiography
Comparison conventional angiography
Outcome carotid stenosis > 70%