time-interleaved parallel i maging approach to separation

1Global Ap

Introductionhas been demimaging of thdifferences b[45] But thistime-interleavtemporal phaband excitatiophase

Theory If Nthat the slicespropose to acusing parallelemployed Foacceleration fso that the ind1 and 2 f1 anof the slices

For the tGR2 4 6 hellip as

Where S1 anddirection ThetGRAPPA

Method Phachannel headexcited In eaimplementedalong the wav

Results and results for theseen the sliceto shorten echIn case of a throughout thout sampling tGRAPPA me

References 5(12) 2010 ((7) Beatty PJ

Figure 1

Time-interleaSuchandrima

pplied Science Lab

n Simultaneous exmonstrated in imprhe whole head [23etween these slices involves additionved approaches suse and calibrationon scheme that tra

N slices are excited s can be separatedcquire data with onl imaging principlor the sake of simfactor R=2 The exdividual coil imagd f2 can be writtenIn a matrix form

RAPPA analogy wblock 2 and their

d the ρ1 represent te similarity betwe

antom and in vivod array (Nova Meach scan 12 time Once the data coveform direction

Discussion Figure same 3 slices exces have been unalho-train length Bytime series acquis

he scan for a more pattern is employethods

(1) Breuer F et a(4) M Blaimer et J ISMRM 2007 1

aved parallel ia Banerjee1 Yuvalb GE Healthcare

Science Lab

xcitation of multiproving the tempor3] Slices that are ee locations and calnal prescan and mch as tGRAPPA h

n data is collected anslates to a simila

simultaneously wd by some linear conly one of these N les Calibration damplicity let us xcitation scheme ises obtained from t

n as S1 ρ1and S2sdotρ2

with acceleration Rcorresponding im

the coil sensitivity en [1a] and [1b] s

o experiments weredical USA) on ae frames were acqorresponding to al

re 2a) shows threcited by the 3 bandiased completely y using this time-isition such as funcrobust reconstructed for all tempora

al MRM 53 684-al JMRI 24 444 1749

imaging appro Zur2 Atsushi TakMenlo Park Califb GE Healthcare

ple slices helps redral resolution of ecexcited simultaneolibration data can

matching of the slichave been proposed

from neighboringar reconstruction p

with N different excombination of theexcitation wavefo

ata is collected frodiscuss the case os shown in Figure these 2 waveforms2 where S1 S2 are t

R = 2 if we denoteages as B1 and B2

and the ldquoidealrdquo imhows that k space

re conducted usina GE 30 T MR75quired Slice t-ARll the waveforms

e slices that were d RF pulse for theThis technique ca

interleaved approactional MRI theretion and to improvl phases the propo

-691 2005 (2) M(2006) (5) Setsom

Figure

oach to separakahashi1 Ajit Shanfornia United Sta San Francisco C

duce the time needcho-planar functioously by a multi-bbe acquired from

ce prescription to sd for multi-phase s

g k-space lines of nproblem even thou

citations the phaseN signals for ex

orms and to syntheom the previous Nof two slice excit1 The phase of th

s are I1 = f1 + f2 anthe coil sensitivitie

e the set of odd k2 respectively an e mage respectively e data of I1 and I2

ng an echo-planar 50 scanner (WaukC a time-interleawere synthesized

excited separatelye 9th time frame Caan be combined wiach slices are co-le is also the flexibve the calibration dosed method shou

Moeller S et al MRmpop K et al MRM

b)

a)

e 2

ation of simultnkaranarayanan1 ates 2GE Healthca

California United S

ded to acquire a fixonal MRI and for band excitation can

a separate acquisslice locations excscans where differneighboring phaseugh the same sam

e of each slice can Fourier transformesize the rest N-1

N phases in each otation only and cohe second slice is ind I2 = f1 ndash f2 respees at slice location

1

k-space lines 1 3 equation similar to 1

S2 and ρ2 are S1 acan also be arrang

sequence incorpokesha WI) Threeaved parallel imag slices were sepa

y by a single-banalibration data waith in-plane accelelocalized between ibility of re-estimadata by averaging

uld be more robust

RM 63 1144-115M 01-152011 (6

taneously exciand Douglas AC are Tirat Carmel IStates

xed number of slicreducing scan tim

n be unaliased by sition where each cited by the multibrent sampling pattees [6] In this work

mpling pattern is em

n be incremented am (FT) or inverse waveform dataset

of which a differenompare it to convinverted by the secectively where f1 ans 1 and 2 and ρ1

5 hellip as block 1 o [1a] can be writte

and ρ1 shifted by Fged in a block for

orated with multibe slices 30 mm apging reconstructionarated in image sp

nd RF pulse Figuras collated from theeration to further rcalibration and th

ating the reconstruprevious time framto EPI phase erro

3 2009 (3) Feinb6) F Breuer et al M

ited slices Kelley3 Israel 3Global Ap

ces [1] Recently itme for diffusion spexploiting coil senslice is excited sepband RF pulse Preerns are employedk we will present mployed in each te

across the excitatioHadamard transfo

ts from the first want excitation waveventional tGRAPPcond waveform (Fand f2 are images o ρ2 are the ldquoidealrdquo

and the set of even

OV2 in the phaserm and reconstruct

band RF pulse wipart were simultan based on ARC

pace by Fourier tra

re 2b) shows slicee first 3 phases Areduce acquisitionhe accelerated acquuction kernel perimes Since the samrs compared to tra

berg DA et al PlMRM 53 981-985

pplied

ts utility pectrum nsitivity parately eviously d in each a multi-emporal

ons such orm We aveform eform is PA with Figure 1) of slices rdquo images

ven lines

e encode ted as in

ith a 32 aneously [7] was ansform

e t-ARC s can be

n time or uisition odically

me read-aditional

los One 5 (2005)

2227Proc Intl Soc Mag Reson Med 20 (2012)