9. History of allergic, anaphylactic or other significant adverse reaction to radiographic contrast media (iodinated or non-iodinated), which cannot be managed by pre-treatment with agents such as steroids or anti-histamines, and which, in the opinion of the investigator, renders the subject unsuitable for routine CT scanning. Subjects who are contra-indicated for CT scanning for other reasons (e.g. ferromagnetic implants, profound claustrophobia), should not be enrolled.