Predicting success of prospective and retrospective gating with dual-source coronary computed tomography angiography: development of selection criteria and initial experience.

BACKGROUND

Prospectively gated coronary computed tomographic angiography (CCTA) with dual-source CT allows substantial reduction of radiation exposure but requires prospective single-phase selection and assessment of likelihood of adequate image quality.

OBJECTIVE

We developed and tested the model for predicting success of prospectively gated CCTA.

METHODS

Retrospectively gated CCTA was acquired with dual-source CT in 162 patients. Two cardiologists assessed by consensus whether diagnostic quality images could have been obtained in a single predefined phase, 70% of R-R interval (70P), thereby identifying patients in whom a prospectively gated scan at 70P would have been successful. Logistic regression models were built with and without a coronary calcium scan. The obtained criteria were applied on 42 additional patients.

RESULTS

By logistic regression, heart rate before CCTA of >or=70 beats/min, maximal heart rate variation before CCTA of >or=10 beats/min, coronary calcium score >or= 400 U, and body mass index (in kg/m(2)) >or= 30 were independent predictors of unsuccessful prospectively gated CCTA using 70P. Excluding coronary calcium score from the model, these same variables in addition to age > 65 years were found to be predictors of unsuccessful prospectively gated CCTA. Applying this model to 42 additional patients, using prospective gating, only 5 segments in 4 patients were nondiagnostic. Mean radiation dose for prospectively gated CCTA was 2.2 +/- 0.8 mSv.

CONCLUSION

Prospectively gated CCTA with dual-source CT can be successfully implemented with consideration of prescan heart rate, heart rate variability, body mass index, and coronary calcium score.