Table 2

Diagnostic Performance and Predictive Value of 64-Slice CT Coronary Angiography for the Detection of ≥50% Stenosis on QCA: Analysis for High, Intermediate, and Low Pretest Likelihood for Obstructive CAD

ObservedPretest Probability, %EstimatedPretest Probability, %nTPTNFPFNKappaSensitivity,%Specificity,§%PPV, %NPV, %+LR−LR
Patient-based analysis: all502541241101820.8498 (94–100)86 (78–91)87 (80–92)98 (93–100)7.000.02
 High78871058017620.7698 (91–100)74 (51–89)93 (85–97)89 (65–98)3.740.03
 Intermediate3953833243800.81100 (87–100)84 (71–93)80 (64–90)100 (90–100)6.380.00
 Low1813661250400.82100 (70–100)93 (81–98)75 (47–92)100 (91–100)13.500.00
Vessel-based analysis: all191,0161817309780.7196 (92–98)88 (86–90)65 (59–71)99 (98–99)8.160.05
 High314201262296050.6896 (91–99)79 (74–84)68 (60–74)98 (95–99)4.630.05
 Intermediate13332402612830.6793 (80–98)90 (86–93)59 (46–70)99 (96–100)9.600.08
 Low626415240900.75100 (75–100)96 (93–98)63 (41–80)100 (98–100)27.670.00
Segment-based analysis: all73,6472283,194193320.6488 (83–91)94 (93–95)54 (49–59)99 (99–99)15.390.13
 High121,4681631,161126180.6490 (85–94)90 (88–92)56 (50–62)98 (98–99)9.200.11
 Intermediate41,219461,1125470.5887 (74–94)95 (94–96)46 (36–56)99 (99–100)18.740.14
 Low3960199211370.6573 (52–88)99 (98–99)59 (41–76)99 (98–100)52.500.27

CAD = coronary artery disease; FN = false negative; FP = false positive; NPV = negative predictive value; PPV = positive predictive value; TN = true negative; TP = true positive; +LR = positive likelihood ratio; −LR = negative likelihood ratio.

  • Observed pretest probability: based on conventional coronary angiography (≥1 significant coronary stenosis as determined by quantitative coronary angiography [QCA]);

  • estimated pretest probability: estimated using Duke Clinical Score;

  • the sensitivity showed a trend with a lower sensitivity in the low estimated pretest probability in the per-segment analysis (p < 0.05);

  • § the specificity showed a trend with a lower specificity in the high estimated pretest probability in the per-patient, per-vessel, and per-segment analysis (p < 0.05, p < 0.0001, p < 0.0001, respectively). Values in parentheses represent 95% confidence intervals.