128-slice Dual-source Computed Tomography Coronary Angiography in Patients with Atrial Fibrillation: Image Quality and Radiation Dose of Prospectively Electrocardiogram-triggered Sequential Scan Compared with Retrospectively Electrocardiogram-gated Spiral Scan

Feasibility of low-dose coronary computed tomographic angiography used in atrial fibrillation patients

OBJECTIVE

The diagnosis of coronary artery disease (CAD) in atrial fibrillation (AF) patients using coronary computed tomography angiography (CCTA) requires a large exposure dosage or repeated examinations. This study evaluates the feasibility of using low-dose CCTA in the double prospectively ECG-triggered high-pitch spiral acquisition mode (Double Flash Spiral mode).

METHODS

Twenty-eight AF patients with suspected CAD were recruited. Double Flash Spiral mode (tube voltage 100 kVp) and iterative reconstruction was used for CCTA examination. Two radiologists cross-evaluated the CCTA image quality. The effective radiation dose was measured for each patient.

RESULTS

Twenty-eight AF patients (10 female, 18 male, mean age 68.8 ± 13.9 y, body mass index 24.3 ± 2.3 kg/cm²) were recruited and 337 artery segments were evaluated. In total, 98.5% (332/337) of the coronary artery segments and 96.4% (27/28) of the AF patients were rated as diagnostically evaluable. Of these 27 diagnosable patients, 17 patients (63%) were diagnosed with multi-vessel stenosis. Besides, 5 of 28 patients (17.9%) have left atrial appendage thrombus. The quality of the integrated image was significantly better than either of the individual first or the second scans, based on segments (P < 0.001) and patients (P < 0.05). The mean effective radiation dose was 1.5 mSv ±0.4 mSv.

CONCLUSIONS

Using the Double Flash Spiral mode at low radiation dose (mean 1.5 mSv), 98.5% of the coronary segments and 96.4% of the scans were of sufficient diagnostic quality.