In vivo quantification of carotid artery wall dimensions: 3.0-Tesla MRI versus B-mode ultrasound imaging.
BACKGROUND
Our aim was to compare common carotid mean wall thickness (MWT) measurements by 3.0-T MRI with B-mode ultrasound common carotid intima-media thickness (CCIMT) measurements, a validated surrogate marker for cardiovascular disease.


RESULTS
B-mode ultrasound and 3.0-T MRI scans of the left and right common carotid arteries were repeated 3 times in 15 healthy younger volunteers (age, 26+/-2.6 years), 15 healthy older volunteers (age, 57+/-3.2 years), and 15 subjects with cardiovascular disease and carotid atherosclerosis (age, 63+/-9.8 years). MWT was 0.711 (SD, 0.229) mm and mean CCIMT was 0.800 (SD, 0.206) mm. MWT and CCIMT were highly correlated (r=0.89, P<0.001). The intraclass correlation coefficients for interscan and interobserver and intraobserver agreements of MRI MWT measurements were larger than 0.95 with small confidence intervals, indicating excellent reproducibility. Power calculations indicate that 89 subjects are required to detect a 4% difference in MRI MWT compared with 469 subjects to detect similar differences with ultrasound IMT in follow-up studies.


CONCLUSIONS
The study data for carotid MRI and ultrasound IMT showed strong agreement, indicating that both modalities measure the thickness of the intima and media. The advantage of MRI over ultrasound is that the measurement variability is smaller, enabling smaller sample sizes and potentially shorter study duration in cardiovascular prevention trials.
Duivenvoorden
R
R
Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
de Groot
E
E
Elsen
B M
BM
Laméris
J S
JS
van der Geest
R J
RJ
Stroes
E S
ES
Kastelein
J J P
JJ
Nederveen
A J
AJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000473:pathology*; D016022:Case-Control Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography; D055815:Young Adult