- adequate assessment of the patient
- formulating an appropriate differential diagnosis based on that assessment
- choosing the appropriate investigation/s to examine that differential (radiology are happy to discuss this, if unsure)
- giving the necessary clinical information to the radiologist to assist in choosing the proper imaging protocol and interpretation of the imaging
- appropriate preparation of the patient for that investigation (analgesia, full bladder, fasting, IV hydration, sedation…)
Given that imaging is a limited resource and often not a completely benign investigation (esp. high radiation dose CT and contrast imaging), appropriate individual risk benefit assessment should be done prior to the ordering of any investigations. Furthermore, you should not be ordering investigations that you do not think are clinically indicated, i.e. on the phone advice of a doctor may or may not have seen the patient.