Nuclear Magnetic Resonance-Bushberg Chapter 14 Diagnostic Radiology Imaging Physics Course Spin Echo:Spin(Proton)Density Weighting Spin Echo:T2-weighting p-weighted (TR=2,400.TE=30) Reduce T1 effects with long TR.accentuate T2 effects with long TE Fat and CSF-relatively bright T2-weighted signal usu.the second echo of a multi-echo sequence Compared with a T1-weighted image-inversion of tissue contrast ◆Short T1 tissues→short T2,long T1 tissues一long T2 .Typical pulse sequence parameters ◆TR:1,500-3,500msec 。TE:5-30msec Highest SNR for SE pulse sequences .Image contrast relatively poor e Spin Echo:T2-weighting Spin Echo Parameters WICNLSE SEOUENCE CONTRAST .T2-weighted (TR>2.000. TE>80) Parameter T1 Contrast Spin Density Contrast T2 Centrast .As TE increased,more T2 t o 10g contrast is achieved at the expense of reduced M TE.imefherepetition. Typical pulse sequence TR parameters 。10m 45 。TR:1,500-3.500msec 。TE:60-150msec ,m a“a 9,19and26May2005 12 Nuclear Magnetic Resonance – Bushberg Chapter 14 Diagnostic Radiology Imaging Physics Course 9, 19 and 26 May 2005 12 © UW and Brent K. Stewart, PhD, DABMP 45 Spin Echo: Spin (Proton) Density Weighting ™ ρ-weighted (TR=2,400, TE=30) weighted (TR=2,400, TE=30) ™ Fat and CSF Fat and CSF – relatively bright relatively bright ™ Slight contrast inversion Slight contrast inversion between WM and GM ™ Typical pulse sequence Typical pulse sequence parameters ™ TR: 1,500-3,500 msec ™ TE: 5-30 msec ™ Highest SNR for SE pulse Highest SNR for SE pulse sequences ™ Image contrast relatively poor Image contrast relatively poor c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2nd ed., p. 397. T1 ρ (TR=2400, TE=30) © UW and Brent K. Stewart, PhD, DABMP 46 Spin Echo: T2-weighting ™ Reduce T1 effects with Reduce T1 effects with long TR, accentuate T2 effects with , accentuate T2 effects with long TE ™ T2-weighted signal usu. the second echo of a multi weighted signal usu. the second echo of a multi-echo sequence ™ Compared with a T1-weighted image weighted image → inversion of tissue contrast inversion of tissue contrast ™ Short T1 tissues Short T1 tissues → short T2, long T1 tissues short T2, long T1 tissues → long T2 c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2nd ed., p. 398. © UW and Brent K. Stewart, PhD, DABMP 47 Spin Echo: T2-weighting ™ T2−weighted (TR > 2,000, weighted (TR > 2,000, TE > 80) TE > 80) ™ As TE increased, more T2 As TE increased, more T2 contrast is achieved at the contrast is achieved at the expense of reduced Mxy ™ Typical pulse sequence Typical pulse sequence parameters ™ TR: 1,500-3,500 msec ™ TE: 60-150 msec c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2nd ed., p. 398. T1 ρ T2 (TR=2400, TE=90) © UW and Brent K. Stewart, PhD, DABMP 48 Spin Echo Parameters Spin Echo Parameters c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2nd ed., p. 399