Order Indications
Indications for Ordering MRI/CT Scans (pdf) – The University of Utah Radiology web site offers a listing of recommended CT/MRI orders by indication
When to Order Contrast (pdf) – South Jersey Radiology Associates offers a quick guide on when & when not to order contrast for body and orthopedic imaging as well as neuroradiology

Radiologic Interpretation
Signs of Congestive Heart Failure on Chest XR (web site) – The Radiological Society of the Netherlands offers this useful summary of expected chest XR findings in congestive heart failure.

Reference Bookshelf
RadiologyEducation.com – A master list of links to educational materials for radiology, curated by a radiologist who works with the University of Iowa Children’s Hospital
Radiology Masterclass – Extremely succinct tutorials designed for UK medical students and residents: Chest XRs, Abdominal XRs, Knee XRs, Ankle XRs etc. All tutorials offer normals, abnormals, and precise descriptions of how to identify the difference.
The Radiology Assistant – Educational web site created by the Radiological Society of the Netherlands which offers expected radiologic findings by condition (as for CHF signs above). This site also offers an iPad app for easier review on the go.
Sonosite e-Learning – Educational web site created by Sonosite which contains case studies, instructional videos on performing ultrasounds, and a media gallery.