[1] Univ Exeter, Med Sch, Exeter, Devon, England
[2] Royal Devon & Exeter Hosp, Exeter EX2 5DW, Devon, England
[3] Med & Healthcare Prod Regulatory Agcy, London, England
[4] NICE, Ctr Hlth Technol Evaluat, London, England
[5] FDA Ctr Devices & Radiol Hlth, Silver Spring, MD USA