A 7-Tesla High Density Transmit with 28-Channel Receive-Only Array Knee Coil.

As more advanced 7T MRI technology continues to emerge, the development of a wider anatomical range of RF coils has become a greater priority. When considering the orthopedic application of knee imaging, the gains from 1.5T to 3T of greater spatial resolution and higher SNR further improve at 7T, which brings further clinical detail and functional imaging to the critical knee structures of the menisci, cruciate ligaments, and articular cartilage [1]. In earlier work at 3T, a local transmit and high-channel receive coil was developed with multiple rows of elements in the S-I direction to allow higher parallel imaging acceleration factors, which reduce scan time and pulsation flow artifacts [2]. These concepts were used as the basis to develop a transmit and 28-channel receive knee coil at 7T. However, 7T presents unique challenges for RF coil design due to the shorter wavelength within the human body. Therefore, several novel design strategies including partial transmitter shielding and ultra-compact preamplifier were utilized.