: We investigated whether coronary artery calcium score CAC in the target lesion on the multidetector computed tomography angiography CTA predicts the addition of the Rotational atherectomy Rota during percutaneous coronary intervention PCI . Lesion CAC on CTA were evaluated with quantitative coronary analysis QCA on coronary angiography for predicting the Rota treatment in 114 consecutive patients 165 target lesions with rst PCI 68 9 years old, females: 17.6 . Rota was added in 8 patients 11 lesions . The lesion length and diameter stenosis on QCA, and lesion length and lesion CAC on CTA were the primary factors associated with the addition of Rota. Using the cut-off value based on receiver operating characteristic analysis, the sensitivity and speci city for predicting the Rota based on QCA was 72.7 in 8 of 11 lesions vessels with Rota and the speci city was 74 in 114 of 154 without Rota in the lesion length of ≥ 23 mm