Recommend a type of diagnostic image, with or without contrast for the following patients:
- A patient with persistent lower back pain resistant to conservative interventions
- A 74-year-old male with dyspnea, productive green phlegm, fever and chills, and malaise
- A 48-year-old female who is 48-hours postoperative complaining of right-calf pain
- When are computed tomography (CT) scans indicated?
- When are magnetic resonance imaging (MRIs) indicated?
- What helps the FNP decided whether to use contrast or not when ordering a CT scan or MRI?
at least 200 words