title: Comparison between magnetic resonance imaging and B-mode ultrasound in detecting and estimating the extent of human carotid atherosclerosis.
abstract: BACKGROUND
  In MRI studies of carotid plaques, ultrasound is used to find plaques, which are later imaged using MRI. The performance in plaque detection has not been compared between the modalities. The aim of the current study was to compare the performance of MRI and ultrasound in detecting carotid artery plaques and measuring extent of atherosclerosis.
  
  
  METHODS
  Subjects with at least one plaque (height≥2·5 mm) on ultrasound were imaged using MRI. The number of plaques and their height was measured in both modalities; plaque area and volume were analysed on ultrasound and MRI, respectively.
  
  
  RESULTS
  Thirty-eight subjects were included. MRI detected plaques in 95% of carotid arteries with a plaque height of ≥2·5 mm on ultrasound and in all carotid arteries with a plaque exceeding 2·5 mm. MRI detected 53% of the plaques with a height below 2·5 mm. The plaque height measured with both techniques correlated significantly, 0·59, P<0·0001. Ultrasound-derived plaque height and plaque area correlated similarly to MRI-derived plaque volume, r = 0·52; P<0·0001 and r = 0·47; P = 0·001, respectively.
  
  
  CONCLUSIONS
  We conclude that MRI has a similar sensitivity to ultrasound in finding carotid artery plaques that are 2·5 mm or higher. In smaller plaques, MRI detects fewer plaques. Multiple carotid plaques seen on ultrasound most often are a misinterpretation of the anatomy and correspond to a single plaque. Plaque height on ultrasound is comparable to plaque height on MRI and correlates fairly well with plaque volume on MRI making it an interesting proxy for plaque burden.
authors.affiliation: The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.|Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Hjelmgren
authors.affiliation: The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Caroline
authors.initials: C
authors.lastname: Schmidt
authors.affiliation: Department of Radiology, Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Johansson
authors.affiliation: The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.|Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Göran M L
authors.initials: GML
authors.lastname: Bergström
mesh_terms: D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000473:pathology; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014463:Ultrasonography
keywords: atherosclerotic disease; atherosclerotic plaque; carotid; magnetic resonance imaging; ultrasound