RF Coils PDF

RF coils Dr. Hayder Jasim Taher PhD of Medical Imaging Outline of my presentation ✓ RF coils. ✓ Volume coils. ✓ Surface coils ✓ Phrased Array coils  RF coils RF coils are one of the most important components that affect image quality in MRI These...

RF coils Dr. Hayder Jasim Taher PhD of Medical Imaging Outline of my presentation ✓ RF coils. ✓ Volume coils. ✓ Surface coils ✓ Phrased Array coils  RF coils RF coils are one of the most important components that affect image quality in MRI These are the coils to transmit the RF pulse and receive the RF signal There may be separate Transmitter and receiver RF coils or a transreceiver coil which serves as both transmitter and receiver coil  RF coils RF coils can be divided into three general categories: Transmit Only Coil- It only transmits signals. Receive Only Coil- It only receive signals. Transmit Receive Coil- It both transmits and receive signsls.  RF coils types Volume coils Surface coils Phrased Array coils Volume coils  Volume coils The volume MRI coils types belong: Circularly Polarized Coil Quadrature coil Bird Cage Coil Crossed Coil Helmholtz Pair Coil Paired Saddle Coil Single Turn Solenoid  Surface coils Surface coils are the coils with the simplest coil design. Basically, it is a loop of wire, either circular or rectangular, that is placed over the region of interest (around the surface of a patient) for increased magnetic sensitivity. As a type of RF coil, they belong into the group of receive only coils. The surface coils have a great SNR for tissues placed near the coil. Therefore, the further the tissue is from the coil, the less sensitive it is. The surface coils are for spines, shoulders, the joint of the jaw (temporomandibular joint), and imaging of other smaller body parts.  Surface coils The common surface MRI coils types are: Array Coil Body Wrap Around Coil Linearly Polarized Coil Saddle Coil  Phrased Array coils These coils merge the benefits of smaller coils (high SNR) with the benefits of larger coils (large measurement field). Moreover, they consist of separate multiple smaller coils that we use individually or combined. There are several types of array coils such as a coupled array, isolated array, and phased array coils, even the patient couch acts as a coil.  Quadrature Coils Quadrature or circularly polarized coils can have either a saddle shape or as a surface coil. Common is that they contain at least two loops of wire, which are placed at right angles to one another. The advantage of this design is that they produce more signal than single loop coils. Nowadays, most volume coils are Quadrature coils.