Magnetic resonance guided focused ultrasound (MRgFUS) is a non-invasive therapeutic that has shown success in the treatment of neurodegenerative diseases. It uses transducer helmet with a large number of ultrasound sources concentrating acoustic energy on a millimetric-sized focal point in the brain. MRI is used in guidance of US treatment; however, poor image quality and thus poor focal precision is observed because the presence of the conductive transducer helmet inhibits the use of a conventional head coil and necessitates the vendor-installed body coil. This work proposes a high-sensitivity, flexible, and ultra-thin head (FUS-Flex) coil for maximized signal-to-noise-ratio (SNR).