Intraoperative MR imaging has become one of the most important concepts in present day neurosurgery. The brain shift problem with navigation, the need for assessment of the degree of resection and the need for detection of early postoperative complications were the three most important motives that drove the development of this technology. The GE Signa System with the "double doughnut" design was the world's first intraoperative MRI. From 1995 to 2007 more than 1,000 neurosurgical cases were performed with the system. The system was used by several different specialties and in neurosurgery it was most useful for complete resection of low-grade gliomas, identification and resection of small or deep metastases or cavernomas, recurrent pituitary adenomas, cystic tumors, biopsies in critical areas and surgery in recurrent GBM cases. Main superiorities of the system were the ability to scan without patient movement to get image updates, the ability to do posterior fossa cases and other difficult patient positioning, the easiness of operation using intravenous sedation anesthesia and the flexibility of the system to be used as platform for new diagnostic and therapeutic modalities.