"Calcium Density of Coronary Artery Plaque and Risk of Incident Cardiovascular Events"
JAMA
http://jama.jamanetwork.com/article.aspx?articleid=1780017
"Conclusions and Relevance  CAC volume was positively and independently associated with CHD and CVD risk. At any level of CAC volume, CAC density was inversely and significantly associated with CHD and CVD risk. The role of CAC density should be considered when evaluating current CAC scoring systems."