E-Z-EM Inc. of Lake Success, N.Y., a manufacturer of contrast agents for gastrointestinal radiology, has entered into a merger with Bracco Diagnostics Inc., the US subsidiary of Milan, Italy-based Bracco Imaging SpA. The latter company will acquire all of the outstanding shares of the former for $21 each, for a total price of around $241 million. The transaction is expected to be completed in early 2008.