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Figure 5 Distribution of IQCA Stenosis Grading Results for Each Group of Segments With the Same Stenosis Grading by Visual CCTA Inspection and Quantitative CCTA Evaluation

Components of each bar total 100%. Each stepwise increase in coronary computed tomographic angiography (CCTA) grading is accompanied by an increase in frequency of higher grade stenoses on invasive coronary angiography–based stenosis quantification (IQCA) (p < 0.001). Frequency of IQCA grade 5 stenoses was higher in segments determined grade 4 by CCTA quantification (B) (21.7%) than by visual inspection (A) (5.8%, p = 0.016). A grading discrepancy of >1 between CCTA and IQCA occurred rarely. For example (A), only 1.9% visual CCTA grade 2 segments were grade 4 on IQCA, indicating that when maximal stenosis within a segment is determined at 25% to 49% on CCTA, 70% stenosis by IQCA can be excluded.