Coronary artery calcium score scan at 100 kVp with tin filtration (Sn100 kVp) prior to coronary computed tomography angiography for overall radiation dose reduction: a prospective cohort study.

BACKGROUND

Reducing radiation dose is a global concern in coronary computed tomography angiography (CCTA). We aimed to investigate whether a coronary artery calcium score (CACS) scan would lead to an overall reduction of radiation dose in CCTA examination and determine its necessity in routine CCTA imaging.

METHODS

A total of 297 patients with suspected coronary heart disease were consecutively enrolled in this prospective cohort study between March 1, 2021, and September 1, 2021. All patients were scanned using a prospective electrocardiogram-triggered sequence acquisition mode on a dual-source computed tomography (CT) scanner. The first 1-150 patients (group A, n=150) were scanned with CACS using tin filtration with low voltage (Sn100 kVp) to guide the CCTA scanning range, whereas the subsequent 151-297 patients (group B, n=147) were scanned using a scout view for the CCTA range. Participant characteristics, number of scans, scan length, actual heart length, CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED), and qualitative analysis were statistically analyzed between the groups.

RESULTS

There was no significant difference in sex, age, height, weight, body mass index (BMI), or heart rate between the 2 groups. The number of scans and scan length (149 of 3 scans at 10.35 cm, 1 of 4 scans at 13.80 cm; P<0.001), CTDIvol of CCTA (16.13 mGy; P<0.04), DLP of CCTA (166.90 mGycm; P<0.001), ED of CCTA (4.34 mSv; P<0.001), and overall ED (4.57 mSv; P<0.001) of group A showed significant differences compared with group B (36 of 3 scans at 10.35 cm, 109 of 4 scans at 13.80 cm, 2 of 5 scans at 17.25 cm; CTDIvol of CCTA at 18.30 mGy; DLP of CCTA at 235.60 mGycm; ED of CCTA at 6.13 mSv; overall ED at 6.13 mSv); meanwhile, actual heart length, qualitative analysis, and diagnostic CT reports were similar between the groups.

CONCLUSIONS

The CACS scan with Sn100 kVp prior to CCTA imaging on dual-source CT could reduce overall radiation dose.