Why Quadrature RF Coils Are Preferred?
1. Higher Signal-to-Noise Ratio (~40% improvement) A quadrature coil uses two coils placed 90° apart , receiving signals in two orthogonal directions. These two independent signals combine constructively , giving: √2 (≈ 1.41×) higher SNR Better image quality, especially for low-signal tissues. More SNR = better resolution, faster scans, or both. 2. Better Sensitivity to Circularly Polarized MR Signal The MR signal emitted by precessing protons is circularly polarized . A single coil picks up only one component of this circular motion. A quadrature coil picks up both components , matching the physics of precession much better → more efficient signal capture. 3. Reduced Noise Noise is random and uncorrelated between the two coils, while MR signal is correlated. When signals combine: Signal adds coherently Noise adds incoherently ➡️ Improves SNR without increasing noise. 4. Less Transmit Power Needed In transmit mode, quadr...