Remodeling of carotid arteries detected with MR imaging: atherosclerosis risk in communities carotid MRI study.
OBJECTIVE
To determine the extent of thickening of the carotid arterial walls that may be accommodated by outward remodeling.


METHODS
Institutional review board approval was obtained at each participating site, and informed consent was obtained from each participant. All study sites conducted this study in compliance with HIPAA requirements. A total of 2066 participants (age range, 60-85 years) from the Atherosclerosis Risk in Communities (ARIC) study were enrolled in the ARIC Carotid MRI Study. Maximum wall thickness and luminal area were measured with gadolinium-enhanced magnetic resonance (MR) imaging in both common carotid arteries (CCAs) and in one internal carotid artery (ICA) 2 mm above the flow divider. Complete data were available for 1064 ICAs and 3348 CCAs. The association of maximum wall thickness with lumen area was evaluated with linear regression, and adjustments were made for participant age, sex, race, height, and height squared.


RESULTS
In the ICA, lumen area was relatively constant across patients with a wall thickness of 1.38 mm or less. In patients with a wall thickness of more than 1.38 mm, however, lumen area decreased linearly as wall thickness increased. Wall area represented a median of 61.9% of the area circumscribed by the vessel at a maximum wall thickness of 1.50 mm +/- 0.05 (standard deviation) and 75.4% at a maximum wall thickness of 4.0 mm +/- 0.10. In the CCA, lumen area was preserved across wall thicknesses less than 2.06 mm, representing 99% of vessels.


CONCLUSIONS
Atherosclerotic thickening in the ICA appears to be accommodated for vessels with a maximum wall thickness of less than 1.5 mm. Beyond this threshold, greater thickness is associated with a smaller lumen. The CCA appears to accommodate a wall thickness of less than 2.0 mm. These estimates indicate that the carotid arteries are able to compensate for a greater degree of thickening than are the coronary arteries.
Astor
Brad C
BC
Welch Center for Prevention, Epidemiology and Clinical Research and Departments of Epidemiology and Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21287, USA. bastor@jhsph.edu
Sharrett
A Richey
AR
Coresh
Josef
J
Chambless
Lloyd E
LE
Wasserman
Bruce A
BA
D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000473:pathology*; D002343:Carotid Artery, Internal / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA