List four indications for dynamic (functional) renal imaging.

1. Suspected renal obstruction (furosemide renogram)
2. Suspected renal artery stenosis with resultant hypertension (captopril renogram)
3. Suspected complications from renal transplantation (e.g., acute tubular necrosis, cyclosporin toxicity, rejection)
4. Suspected urine leak in the setting of renal transplantation