Coronary CT angiography for acute chest pain triage: Techniques for radiation exposure reduction; 128 vs. 64 multidetector CT

Background: Coronary CT angiography (CCTA) is used daily in acute chest pain triage, although exposing patients to significant radiation dosage. CCTA using prospective ECG gating (PG CCTA) enables significant radiation reduction Purpose: To determine whether the routine use of 128 vs. 64 multidetector CT (MDCT) can increase the proportion of patients scanned using PG CCTA technique, lowering radiation exposure, without decreasing image quality. Material and Methods: The study comprised 232 patients, 116 consecutive patients scanned using 128 MDCT (mean age 49 years, 79 men, BMI 28) and 116 consecutive patients (mean age 50 years, 75 men, BMI 28) which were scanned using 64 MDCT. PG CCTA was performed whenever technically permissible by each type of scanner: 64 MDCT = stable heart rate (HR) <60/min and weight <110 kg; 128 MDCT = stable HR < 70/min and weight <140 kg. All coronary segments were evaluated for image quality using a visual scale of 1-5. An estimated radiation dose was recorded. Results: PC CCTA was performed in 84% and 49% of the 128 and 64 MDCT groups, respectively (P < 0.0001). Average image quality score were 4.6±0.3 and 4.7±0.1 for the 128 and 64 MDCT, respectively (P = 0.08). The mean radiation dose exposure was 6.2±4.8 mSv and 10.4±7.5 mSv for the 128 and 64 MDCT, respectively (P = 0.008). Conclusion: The 128 MDCT scanner enables utilization of PG CCTA technique in a greater proportion of patients, thereby decreasing the related radiation significantly, without hampering image quality.