MRI PLAQUE BURDEN OF THE CAROTID ARTERIES AND AORTA: REPRODUCIBILITY, AGE, SEX AND SYSTEMIC DISTRIBUTION

INTRODUCTION: This cross sectional study was conducted to test reproducibility of analysis of MRI parameters in carotids and thoracic descending aorta (TOA), evaluate the correlation of plaque burden and associations with subject age and gender. METHODS: Three hundred subjects, with cardiovascular risk factors, underwent a black blood MRI of both carotids and TOA. Mean wall area, wall thickness, lumen area, total vessel area and wall area/total vessel area (WA/TVA) ratio were manually measured. Inter-reader and intra-reader-reproducibility was tested on 187 and 20 randomly chosen subjects respectively. RESULTS: The intra-observer-reproducibility for the analysis was high (Intraclass-Correlation-Coefficients (ICC’s >0.8), except mean WA/TVA ratio of TOA. Similarly, the inter-observer reproducibility was acceptable (ICC’s >0.7 for mean wall area, lumen area and total vessel area). MRI parameters in aorta and carotids increased with age for both sexes (p<0.001). Except for mean wall thickness of TOA and WA/TVA ratio, MRI parameters were significantly higher in males than in females. All MRI measurements except the mean wall thickness and WA/TVA ratio were highly reproducible. There was good correlation for mean wall area between carotids and aorta compatible with the systemic nature of atherosclerosis. Similar to clinical presentation of cardiovascular diseases we found greater values in most MRI parameters (except for WA/TVA ratio) in males than in females and with increasing age. CONCLUSIONS: These data suggest that analysis of most MRI measurements of plaque burden is reproducible and that there is correlation between plaque burden between carotids and aorta validating the systemic distribution of the disease.