To assess feasibility of using novel calcium subtraction software on Coronary CTA (CCTA) scans in patients with coronary stents to assess image quality of underlying native arteries.Coronary stents are usually associated with artifacts that limit assessment of instent restenosis

Subtraction ( using novel software) can be used to remove calcified plaques from the coronary arteries seen on CCTA scans.The calcium score scan can be used as the non-contrast data for subtraction.Subtraction is to remove blooming and beam hardening artifacts.The resultant images is a lumenogram, only the contrast filled lumen is displayed Software was developed to perform calcium subtraction of coronary arteries on 320MDCT.Calcium subtraction software has the potential to perform stent subtraction as–Stents are metallic and density may be higher or lower than calcium...

There were 38 coronary stents in 19 patients.Image quality was visually assessed to be adequate to good in 23 (60 %) stents and was excellent in 7 (18 %) Image quality was considered to be in the poor or unevaluable in 8 (21%) of stents .The average heart rate in all patients was 57 bpm.In those with multiple stents ,sometimes one stent was unevaluable. Average breathing difference was measured from position of distal RCA between pre-contrast scan (calcium score equivalent) and CCTA scan , was...

Coronary stent subtraction seems to be feasible on routine CCTA scans performed on a 320MDCT scanner, but to achieve good subtraction results and visualization of the native coronary arteries, assessed visually, this appears best in patients with low heart rates In addition as poor subtracted image quality also occurred for unknown reasons, improvement in the subtraction algorithm seems also to be needed.Diagnostic accuracy of coronary stent subtraction on CCTA to assess for instent restenosis, compared to invasive coronary angiography will require future studies.