San Francisco, California, January 6, 2011 - From left, Dr. Ellen Air, a clinical fellow, and University of California San Francisco Medical Center neurosurgeon Dr. Philip Starr listen to a question from Dr. Alexander Papanastassiou, a visiting doctor from the University Texas Health Science Center San Antonio, during the iMRI surgery of patient Linda Sharp at UCSF Medical Center. The iMRI procedure uses Deep brain stimulation (DBS), which has been used for over a decade to treat movement disorders such as Parkinson's disease, essential tremor, and dystonia. DBS uses a pulse generator implanted in the chest, similar to a pacemaker, to deliver pulses to specific regions of the brain via a permanently implanted electrode. In the U.S., DBS is normally done while the patient is awake, because the surgeon needs to induce the symptoms (like the involuntary movements of Parkinson's) to know if he's in the right place, and if the patient is unconscious, the symptoms can't be induced. Many patients find it hard to tolerate. Their head is clamped in a frame, they're aware of their surroundings, and the surgeon is deliberately producing tremors and twitches while they lie there...Interventional MRI (or iMRI) allows surgeons to implant these electrodes while the patient is unconscious taking advantage of MR imaging in real time by performing procedures inside the scanner itself.