It may be possible to reduce the use of<unk><unk>  in ED patients requiring<unk>  contrast for CT or other radiographic evaluation
Data is sparse, however, and any guidelines should be utilized with that in mind, and in the context of local policies.
Creatinine screening prior to IV contrast
Thrombolytics for pulmonary embolism
Formal echocardiography
Balloon tamponade for massive GI bleeding
Renal ultrasound
Thrombolytics for STEMI
Thromboelastography 
Oral contrast for abdominal and pelvic CT