Brainlab, the digital medical technology company, agreed to acquire VisionTree, a San Diego based company that develops cloud-based, patient-centric data collection and health management solutions. Financial terms were not disclosed. "I believe that patient data must ultimately be controlled by the patient. The acquisition of VisionTree adds a tool to our portfolio that will give the patient more control over the data that is generated by our systems for the benefit of better treatment," Stefan Vilsmeier, Brainlab President and Chief Executive Officer.