Your article “Radiology being transformed by cloud, proponents say” presents an interesting usage of cloud-based radiology, backed with practical examples of networks that are employing this model. Because the model encompasses both cloud-based file storage and file exchange, it seems on first blush to be a significant advance beyond cloud-based exchange services.
However, I would submit that the cloud-based service for medical information exchange that our facilities have been using since 2010 has fewer limitations than—and several advantages over—the model your article discusses. Here's why:
The primary limitation of the model in the article is that the cloud-based storage system has limited access. That is, access to images and files is restricted to members of the network and further restricted by whatever contractual relationships bind the network together.