High-resolution magnetic resonance imaging (MRI) with flow suppression not only 
provides useful information on luminal and wall areas of the carotid artery but 
also can identify the principal tissue components of the carotid atherosclerotic 
plaque. The effects of intensive lipid-lowering therapy on these MRI tissue 
characteristics were examined in patients with coronary disease (CAD). Eight CAD 
patients who have been receiving intensive lipid-lowering treatment (niacin 2.5 
g/d, lovastatin 40 mg/d, and colestipol 20 g/d) for 10 years in the Familial 
Atherosclerosis Treatment Study (FATS) follow-up were randomly selected from 
among 60 such treated patients. Eight CAD patients who were matched to the 
treated patients for age (+/-3 years), baseline low density lipoprotein (+/-5 
mg/dL), and triglycerides (+/-50 mg/dL) but who had never been treated with 
lipid-lowering drugs were selected as controls. For each of these 32 carotid 
arteries, luminal and plaque areas were measured by planimetry, in a blinded 
protocol, from the magnetic resonance image that showed most plaque. Fibrous 
tissue, calcium, and lipid deposits were identified on the basis of established 
criteria. Plaque composition was estimated as a fraction of total planimetered 
area. Patients treated with 10-year intensive lipid-lowering therapy, compared 
with control subjects, had significantly lower low density lipoprotein 
cholesterol levels (84 versus 158 mg/dL, respectively; P<0.001) and higher high 
density lipoprotein cholesterol levels (51 versus 37 mg/dL, respectively; 
P<0.001). As a group, treated patients, compared with untreated control 
subjects, had a smaller core lipid area (0.7 versus 10.2 mm(2), respectively; 
P=0.01) and lipid composition (1% versus 17%, respectively). Group differences 
in luminal area (55 [treated] versus 44 [control] mm(2), P=NS) and plaque area 
(58 [treated] versus 64 [control] mm(2), P=NS) tended to favor treatment. MRI 
appears useful for estimating carotid plaque size and composition. 
Hyperlipidemic CAD patients frequently (97%) have at least moderate (>/=40% area 
stenosis) carotid plaque. In this case-control study, prolonged intensive 
lipid-lowering therapy is associated with a markedly decreased lipid content, a 
characteristic of clinically stable plaques.