The reliability of high resolution MRI in the measurement of early stage carotid wall thickening.
OBJECTIVE
To study the repeatability of common carotid mean wall thickness (MWT) measured with high resolution MRI, in comparison with intima media thickness (IMT) assessed by ultrasound and to investigate the relative capabilities of these two modalities.


METHODS
Ten healthy volunteers and 10 subjects with carotid artery atherosclerosis were imaged with both high resolution MRI and US. Measurement of both MWT and IMT was performed by three blinded observers. Intra- and inter-observer repeatability was calculated and a Bland-Altman plot used to compare IMT and MWT. Circumferential variation in arterial wall thickness was also evaluated.


RESULTS
Intra- and inter-observer repeatability were comparable between IMT and MWT. The Bland-Altman plot showed a difference between IMT and MWT in controls with a trend towards equivalence in atherosclerotic patients. Analysis of circumferential variation in wall thickness by MRI identified greater focal thickening in patients compared with controls (p<0.001), which was not evident with ultrasound (p=0.98).


CONCLUSIONS
MRI and ultrasound have similar repeatability for the assessment of carotid wall thickness. There are differences between MWT and IMT, potentially due to the inclusion of the adventitia by MRI which, in addition to better detection of focal thickening, may provide a more complete estimation of early stage atherosclerosis.
Boussel
Loic
L
Department of Radiology, University of California, San Francisco, VA Medical Center, San Francisco, California 94121, USA, and Centre de Recherche en Nutrition Humaine Rhône-Alpes, Hôpital Edouard Herriot, Lyon, France. loic.boussel@gmail.com
Serusclat
André
A
Skilton
Michael R
MR
Vincent
Fabrice
F
Bernard
Sophie
S
Moulin
Philippe
P
Saloner
David
D
Douek
Philippe Charles
PC
D000328:Adult; D000368:Aged; D002340:Carotid Artery Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology; D016022:Case-Control Studies; D003238:Connective Tissue / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; 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