Background Recently published NICE guidance has outlined an increasing role for CT coronary angiogram (CTCA) in the assessment of patients with chest pain. This is likely to result in an exponential increase in the number of CTCAs. We report a model for undertaking CTCA with low contrast dose providing excellent image quality and correlation with invasive coronary angiography.
Method Over 800 CTCAs have been undertaken at our centre in the last year. We have refined our protocol to deliver an average contrast volume of 30mL (range 22–38 mL), providing excellent image quality and invasive angiographic correlation, using: 1. Prospective ECG-gating for all acquisitions, with software based motion correction where necessary. 2.?Smart monitoring protocol for image acquisition. 3.4–6 sec contrast bolus injection at 4.5–6.5 mL/sec injection.
Results 200 consecutive scans were acquired for a range of indications, using 22–38 mL iodine based contrast (Omnipaque 350). Contrast was injected for 4–6 seconds, at 4.5–6.5 mL/sec based on BMI, calcium score, previous coronary stents or coronary artery bypass grafts. 40% patients subsequently underwent invasive coronary angiography +/- pressure wire studies for functional assessment and percutaneous intervention. Image quality and invasive angiographic correlation was excellent (>98% anatomical correlation).
Conclusion Using our model excellent image quality and accuracy comparable to conventional coronary angiography can be achieved, using low contrast volume. Our protocol can be used in patients with impaired renal function and provides limited cost saving compared to conventional protocols.