Approximately 6 million Americans have brain aneurysms, a condition that occurs when a weak or thin spot develops on a blood vessel in the brain causing it to balloon. Often, these do not cause symptoms and go undetected, but every year an estimated 30,000 Americans experience a ruptured aneurysm that bleeds into the brain causing a life threatening injury. Immediate medical treatment is necessary to prevent stroke, nerve damage or death, and includes surgery or coiling. Coiling is an approach that blocks blood flow to the aneurysm by filling it with platinum coils. While less invasive than surgery, the likelihood of future aneurysm recurrence and subsequent treatment is higher with coiling. In an effort to lower the risk for repeat aneurysm treatment after coiling, Northwestern Medicine researchers are examining a new type of gel-coated coil to determine if it is more effective than the standard bare coils in preventing aneurysm recurrence.