Interobserver reliability in the assessment of coronary stenoses by multidetector computed tomography

To determine the interobserver reliability for grading coronary stenosis severity with coronary computed tomographic angiography (CCTA).

Five readers independently reviewed 40 CCTA studies, first the axial images alone, then in combination with multiplanar reconstructions. The stenosis severity in each segment was scored on a 5-point scale. Intraclass correlation (ICC) analysis was performed to assess interobserver reliability on a segmental basis.

The reliability was good to moderate in the right coronary artery, left main artery, left anterior descending artery and branches, and the proximal circumflex (ICC: 0.44-0.75) but fair to poor for the posterior descending artery, the posterolateral branch, the obtuse marginal branches, and the distal circumflex (ICC: 0.15-0.39). The ICC correlated with the reference diameter. Although there was no significant difference in the ICC between the scanner types, there were more unevaluable segments in the 16-row scanner compared with the 64-row scanner (2.4 vs 1.4 segments/patient). Addition of multiplanar reconstruction to axial images led to fewer uninterpretable segments and reclassification of stenosis grade in 23% of the segments.

Interobserver reliability for stenosis severity by CCTA varies between segments and correlates with the reference diameter.