Download Multichannel Technology and Parallel Imaging1 - Magnetic Resonance Imaging - Lecture Slides and more Slides Radiology in PDF only on Docsity! Multichannel Technology & Parallel Imaging docsity.com 1) The Physics of Clinical MR, for Neuroradiology, Taught Through Images AUTHORS: VAL M. RUNGE1 MD, WOLFGANG R. NITZ2 PHD, STUART H. SCHMEETS2 BS, RT, WILLIAM H. FAULKNER, JR.3 BS, RT, NILESH K. DESAI1 MD 2 References: 2) The Physics of Clinical MR, Focusing on the Abdomen, Taught Through Images docsity.com Multichannel Coil (cont.) Circularly-polarized (CP) coil led to a ~ 40% increase in SNR (two-element coil). Also called a ―quadrature coil‖. Recent development: Multichannel technology • Coil uses multiple elements (―loops‖) in phased array with overlapping anatomical coverage Each element acquires MR signals from the entire region. Highest signal in closest proximity to the element. Small element size higher received signal / higher overall signal • RF hardware uses multiple channels for receiving signal from multiple elements. 5 docsity.com Multichannel Coil (cont.) Putting the coil and RF system together… • Signal from each element is (ideally) transferred through its own high-bandwidth RF channel. • Reconstruction corrects element-to-element signal variations before forming the final image. • Advanced reconstruction and storage hardware necessary to process the rapid inflow of information. 6 docsity.com Multichannel Coil (cont.) Figure 1 shows element arrangement for an 8- element head coil, and images acquired from each element, together with the final single combined image. Note that images from each surface element show greater sensitivity near the element. 7 docsity.com Multichannel Coil (cont.) Figure 2 shows element arrangement for a 12- element body coil, with six of the elements activated, and images acquired from each element together with the final single combined image. Typically, the scanner software routinely reconstructs the signal from all elements and provides only the combined image. Note that images from each surface element show greater sensitivity near the element. 10 docsity.com Figure 2 (Ref #2) 11 The scan sequence employed was trueFISP with spectral fat saturation. This image depicts two large liver hemangiomas. docsity.com Multichannel Coil Example #1 Case study: Axial T1- and T2-weighted images of the brain Figures 3A,C (on left) use a standard CP coil Figures 3B,D (on right) use an eight element, phased array coil MR system uses eight, high-bandwidth, RF receive channels All pulse-sequence parameters same between left and right figures. T1 comparison shows increase in SNR, improved gray versus white matter distinction, and improvement in anatomic definition (e.g., cortical gyri). T2 comparison shows increase in SNR, improved definition of gray matter, and improved visualization of the gray matter nuclei. 12 docsity.com
