Stroke: magnetic resonance angiography and Duplex ultrasonography may help to rule out atherosclerotic carotid artery disease.

Clinical bottom line (level 1b-)

  1. A third of patients with suspected atherosclerotic carotid artery disease had it.
  2. Magnetic resonance angiography (LR-0.10) and duplex ultrasound (LR-0.23) were both effective ways of ruling out carotid artery disease, though MRA was better.
  3. Magnetic resonance angiography (LR+3.63) and duplex ultrasound (LR+4.55) were both fairly effective ways of diagnosing carotid artery disease, though ultrasound was better.
Mittl et al: Stroke 1994; 25: 4-10
Expires December 2002

The study

Setting: general hospital, Philadelphia

38 patients (aged range 48 to 80 years; mean 66, 53% male) clinically suspected atherosclerotic carotid artery disease

Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:
  • percutaneous catheter arteriograms- at least two view and in most four view biplane selective common carotid arteriograms evaluated 70 vessels,and a non-selective aortic arch injection was performed in the other 3
Diagnostic test: Magnetic resonance angiography performed on a 1.5-T system using an anterior-posterior neck coil. 110 1.5 mm axial partitions covering the region from the aortic arch to the carotid siphon, and Duplex ultrasonography performed on a Hewlett-Packard Sonos 1000 colour duplex system using a 7.5 MHz linear array transducer with 5.6 MHz Doppler frequency.
  • There were 38 patients in 73 vessels.

The evidence


diagnostic test 70-99% stenosis not 70-99% stenosis LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
magnetic resonance angiography 61 5 3.63
(2.74 to 4.80) 		61.0% 0.10
(0.04 to 0.24) 		4.00%
duplex ultrasonography 17 4 4.55
(2.35 to 8.83) 		68.0% 0.23
(0.09 to 0.57) 		10.0%
total 66 153

Comments

  1. Although there were only 38 patients, there were a total of 219 magnetic resonance arteriographs (73 times three independent neurologists), but only 66 ultrasonographs (only one neurologists looked at these).

Citation

  1. Mittl RL, Broderick M, Carpenter JP, et al: Blinded-reader comparison of magnetic resonance angiography and duplex ultrasonography for carotid artery bifurcation stenosis. Stroke 1994; 25: 4-10
Contributor: Clare Wotton and Musab Hayatli, December 1999
Reviewer:

Clinical Question.
Patient suspected atherosclerotic carotid artery disease
Intervention or Exposure magnetic resonance angiography and duplex ultrasonography
Comparison arteriography
Outcome diagnosis 70-99% stenosis