eCS and nCACS had similar area under the curve ( AUC ) for the prediction of severe CACS ( 400 ) ( 0.77 , 95 % CI 0.68-0 .86 and 0.79 , 95 % CI 0.72-0 .88 ) or obstructive CAD ( 0.63 , 95 % CI 0.54-0 .72 and 0.63 , 95 % CI 0.55-0 .73 ) .