[1] Univ Washington, Dept Radiol, Seattle, WA 98104 USA
[2] Univ Washington, Dept Pathol, Seattle, WA 98104 USA
[3] Univ Washington, Dept Radiat Oncol & Neurol Surg, Seattle, WA 98104 USA
[4] Univ Washington, Dept Med, Seattle, WA 98104 USA
[5] Univ Washington, Dept Neurol Surg, Seattle, WA 98104 USA