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Wednesday, June 1, 2011

SE

Spin Echo

T1 weighted images are achieve using a short TE and short TR
T2 weighted images are achieve using a long TE and long TR
Proton density images are achieve using a short TE and long TR

Monday, May 2, 2011

The abbreviation of sequence name

SE (spin echo) for all routine examinations, T1 & T2 & proton density contrast

IR (inversion recovery) especially for heavily T1 weighted sequences in pediatrics

STIR an IR sequence to suppress the signal originating from fat, for orthopedics

FLAIR an IR sequence to suppress the signal originating from water, also called Dark-Fluid-IR; for multiple sklerosis

FLASH a gradient echo sequence with T1 contrast; also called SPGR, T1-FFE

FISP a gradient echo sequence with T1/T2 contrast; also called GRASS or FFE

PSIF a time inversed Fisp gradient echo sequence with T2 contrast, also called CE-FAST

TurboFLASH a fast gradient echo sequence with T1 contrast; also called TFE

DESS a 3D multiecho gradient echo sequence with T2 contrast for orthopedic imaging; Siemens proprietary sequence

CISS a 3D multiecho gradient echo sequence with high resolution T2 contrast for inner ear imaging with reduced flow artifacts; Siemens proprietary sequence

MEDIC a multi echo gradient echo sequence with T2 contrast for neck, c-spine and orthopedic imaging; improved spinal cord contrast, no visible artifacts; Siemens proprietary sequence

TurboSE a multiecho spin echo sequence with T1 & T2 & Proton density contrast; also called FSE or TSE; improves acquisition time typ. by factor 3 to 4 compared to a standard SE

TurboIR, TurboSTIR, TurboFLAIR are IR sequences with TurboSE benefits (see IR, STIR, FLAIR)

single shot TurboSE a very fast TurboSE sequence with heavy T2 contrast which collects all image information in one single run with up to 240 echos; MRCP, urography and myelography

HASTE a single shot multiecho spin echo sequence with T2 contrast in half fourier technique; for uncooperative patients, myelography, urography and MRCP; one image in less than 1 sec.

EPI a single shot ultrafast sequence with T2 contrast; acquires 128 echos in about 100ms to freeze motion; diffusion, perfusion, fMRI

TOF time-of-flight or inflow angiography based on blood exchange in the vessels; uses 2D and 3D gradient echo sequences; mainly for arteries in the brain

PC phase contrast angiography based on the phase information; slow acquisition times; slowly replaced by contrast enhanced angiography

CE MRA or TurboMRA utilize the fast relaxation of intravenously injected contrast; 3D acquisition in 10 to 20 seconds only; no flow artifacts; abdominal and peripheral angiography