Coronary CT in Australia has high positive predictive value unaffected by site volume: An analysis of 510 positive CTCA scans with invasive angiographic correlation

Abstract Background It was hypothesized that the accuracy of coronary CT angiography would be affected by case volume of the referring sites. Methods The positive predictive value (PPV) of CTCA performed at a tertiary hospital specialising in cardiothoracic medicine and services with lower case-volumes were calculated. The tertiary hospital used as the high case-volume reference centre was The Prince Charles Hospital, which performed >1500 CTCA scans per annum over the study period. The low case-volume services used in the study were suburban radiology services, each with Results The positive predictive value (PPV) of the high case-volume group (n = 199) was 0.7538 . The PPV of the pooled low case-volume services (n = 589) was 0.7331 , p = 0.604, with no statistically significant difference in positive predictive values. Conclusions There was no significant difference in PPV between the two groups. This suggests that high-volume and lower-volume sites both have high PPV in Australia, above the published pooled PPV of four large prospective diagnostic accuracy studies (Miller et al., 2008; Budoff et al., 2008; Meijboom et al., 2008; Achenbach, 2007).