Evidence review

Clinical and technical evidence

Regulatory bodies

A search of the Medicines and Healthcare Products Regulatory Agency website revealed 2 manufacturer field safety notices (FSNs) regarding software issues. The first FSN was published in 2013 to notify users that using software (version syngo CT2012B) may lead to a system display freeze during interventional procedures. The second FSN, published in 2015, states that the use of a perfusion scan mode (Adaptive 4D spiral, typically used for critical diagnostic examinations) in combination with the Patient Handling System PHS1600 could terminate the scan. No MHRA Medical Device Alerts were found for this device and no reports of adverse events were identified from a search of the US Food and Drug Administration (FDA) Manufacturer and User Device Facility Experience (MAUDE) database.

Clinical evidence

Two searches were performed to find publications relevant to the Somatom Definition Edge in people who are difficult to image (see appendix for search strategies). No relevant publications were found. There is little evidence available on the effectiveness and safety of particular CT scanner models in diagnosing CAD in difficult‑to‑image subgroups because of the relatively rapid evolution of CT technology, particularly software enhancements. The available general evidence points to the key technical parameters of a scanner that determine suitability in this application: temporal resolution, spatial resolution and acquisition time.

Recent and ongoing studies

No ongoing or in‑development trials on the Somatom Definition Edge for cardiac patients were identified.

Costs and resource consequences

It was not possible to estimate the future NHS usage of the Somatom Definition Edge for the relevant population. In NICE diagnostics guidance on new generation cardiac CT scanners, it is estimated that the number of people in England in whom imaging is difficult with earlier generation CT scanners may range from 10 million to 18 million. This may be indicative of future NHS usage.

According to the manufacturer, the device is being used at 6 NHS centres.

There will be no need to change the way in which current services are organised or delivered. No other additional facilities or technologies are needed alongside the technology.

No published evidence on resource consequences was identified in the systematic review. However, an economic evaluation by Westwood et al. (2013) contains a model assessing the cost‑effectiveness of invasive coronary angiography (ICA) alone, ICA following a positive CT scan using new generation CT scanners and new‑generation CT scanning alone in difficult‑to‑image subgroups with suspected or known CAD. Westwood et al. (2013) do not mention the Somatom Definition Edge, but include high-end scanners from the NICE diagnostics guidance on new generation cardiac CT scanners. They report that in patients with suspected CAD, the 'CT scanner only' strategy is the most cost‑effective approach compared with the other strategies.