Relationship between Coronary Iodine Concentration Determined Using Spectral CT and the Outcome of Percutaneous Coronary Intervention in Patients with Chronic Total Occlusion

Purpose: To evaluate the feasibility of coronary iodine concentration (CIC) by using spectral CT in the assessment of the outcome of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). Materials and Methods: In total, 50 consecutive patients underwent preprocedural coronary CT angiography with spectral CT prior to their staged PCI for CTO between June 2017 and July 2018. Iodine density maps, referred to as iodine-no-water maps throughout, with spectral CT provided the CIC at proximal CTO (CTO-CIC). Depending on the outcome of PCI, all CTO lesions were divided into two groups: failed PCI and successful PCI. The receiver operating characteristic curve was used to determine the cutoff values of CTO-CIC in the assessment of the outcome of PCI for CTO. Results: Of the 50 CTO lesions in 50 patients, 34 (68%) and 16 (32%) were assigned to the successful PCI and failed PCI groups, respectively. The mean CTO-CIC was significantly less in the failed PCI group than in the successful PCI group (1.3 mg/mL +/- 0.9 [standard deviation] vs 5.2 mg/mL +/- 2.5; P < .001). A low CTO-CIC (<= 2.5 mg/mL) predicted failed PCI with 87% sensitivity, 79% specificity, 79% positive predictive value, and 90% negative predictive value. At multivariable analysis, the low CTO-CIC was significantly associated with the failed PCI (odds ratio, 27.0; 95% confidence interval: 4.9, 147.6; P < .0001). Conclusion: The CTO-CIC determined by using spectral CT may be useful in the assessment of the outcome of staged PCI for CTO. (c) RSNA, 2020 Summary By using spectral CT for coronary angiography before percutaneous coronary intervention (PCI) for chronic total occlusion (CTO), a low coronary iodine concentration (<= 2.5 mg/mL) at the entry of the CTO lesion is associated with failure of successful antegrade PCI for CTO.