Release Notes R002

Application Guide
& Release Notes
Application Guide
&
Release Notes
Inner-volume-imaging
(IVI) EPI C2P
Release 002
Multi-Band
3 June 2014EPI C2P
Release 010b
13 December 2013
TMII
Translational and Molecular Imaging Institute
Conditions of Use
This package is provided to support collaborative research projects
between the Icahn School of Medicine at Mount Sinai (ISMMS) and
University of Minnesota and users of Siemens MRI equipment, in
accordance with a current C2P agreement.
Authors
Junqian Xu, Ph.D.
Translational and Molecular Imaging Institute
Icahn School of Medicine at Mount Sinai Edward J. Auerbach, Ph.D. Center for Magnetic Resonance Research University of Minnesota 1 Table of Contents
Overview ...................................................................................
3
Sequence Description ...............................................................
4
Hardware and Software Requirements .....................................
5
Installation Procedure ...............................................................
6
Usage ........................................................................................
7
Important Issues (not bugs) ......................................................
12
Known Bugs ……......................................................................
13
Version Changes .......................................................................
14
Acknowledgment .................................................................... ..
15
2 Overview
Inner-volume-imaging (IVI) uses orthogonal excitation and
refocusing RF pulses to selectively refocus the magnetization from
a limited field of view (reduced FOV). In single shot spin echo EPI
diffusion imaging, it has the advantage of reducing the EPI
readout, hence reducing susceptibility related distortions, when
imaging small anatomical structures, such as optic nerve, spinal
cord, or prostate.
To improve the signal-to-noise (SNR) efficiency, a pair of
refocusing/inversion pulses can be applied in the phase-encoding
direction in a driven equilibrium fashion.
Experimental
Combining multiband RF excitation with IVI has not been fully
tested. More detailed information about the multiband pulse
sequence and image reconstruction implementation can be found
at the CMRR multiband C2P download page:
www.cmrr.umn.edu/multiband
3 Sequence Description
The pulse sequences in this package are based on the product
ep2d_diff sequences from Siemens.
More detailed information about the IVI EPI diffusion pulse
sequence implementation can be found in the following
references:
1.
Jeong EK, Kim SE, Guo JY, Kholmovski EG, Parker DL.
High-resolution DTI with 2D interleaved multislice reduced
FOV single-shot diffusion-weighted EPI (2D ss-rFOV-DWEPI)
Magn. Reson. Med., 54, 1575–1579, 2005 [PubMed]
2.
Xu J, Shimony JS, Klawiter EC, Snyder AZ, Trinkaus K,
Naismith RT, Benzinger TLS, Cross AH, Song SK. Improved
in vivo diffusion tensor imaging of human cervical spinal cord.
NeuroImage, 67, 64-76, 2013 [PubMed]
The accompanying spinal cord DTI post-processing scripts
can be downloaded from:
http://sourceforge.net/projects/spinedti
More detailed information about multiband pulse sequence can be
found at the CMRR multiband C2P download page.
4 Hardware and Software Requirements
Versions of the inner-volume-imaging EPI sequences will be
available for three Siemens software versions, supporting several
system types. It may be possible to use the sequences with other
scanners not listed with below (e.g. 1.5T systems), but
compatibility has not been tested.
VB17A: MAGNETOM Trio (TQ-engine), MAGNETOM Verio 3T (VQengine), and MAGNETOM 7T.
(Released)
VD13A-SP4: MAGNETOM Skyra 3T (Skyra-XQ).
(To be released)
VD13D: MAGNETOM Prisma 3T.
(To be released)
5 Installation Procedure
Important: please install the CMRR Multiband C2P
(development release) first!
1.
Please skip this step unless errors are encountered in
step 8: Restart the system (reboot host and MRIR, or restart
image calculation and the syngo Exam task card). This is
necessary to unload possibly locked shared objects.
2.
Login as “Advanced User”.
3.
Extract the .zip file to a temporary directory
4.
Open a command window from Windows start menu -> run
… -> “cmd”.
5.
Open “ideacmdtool” from the command window.
6.
Choose “2” PAS unload, then type “q” to quit
7.
Run the installer .bat file
8.
If the installer reports any error, please restart the system and
try again.
9.
If a sample protocol is available for your system, it will appear
at the end of the USER tree in the Exam Explorer. If a sample
protocol is not available, create a default protocol in Exam
Explorer by selecting Insert Sequence, USER, then
tmii_ep2d_diff_ivi for the desired sequence variant.
6 Usage
The sequence is based on the Siemens product ep2d_diff
sequence; most of the protocol parameters are the same. The
most important changes appear on the following measurement
cards:
Routine Card
FoV phase: This parameter determines the IVI slab thickness in
the phase encoding direction. The Phase oversampling
parameter increases the slab thickness by the input percentage.
Slice group: multiple slice groups are allowed for multi-slicemulti-angle (MSMA). (see Important Issues)
Multi-band accel. factor: Ref. CMRR multiband C2P release note
7 Contrast/Common Card
Magn. preparation: Slice-sel. IR and Non-sel. IR can be selective
with monopolar diffusion scheme to provide double inversion for
magnetization outside of the excited slice for efficient multi-slice
imaging. The order of the IR and fatsat module is switched from
the Siemens default to place IR after fatsat to minimize delays
between the two refocusing/inversion pulses.
Grad rev. fat suppr.: If enabled, the polarity of the slice select
gradients will be reversed between the pair of refocusing/inversion
pulses in the phase-encoding direction. This can provide effective
fat suppression at no cost in time or SAR. However, it can also
result in signal losses in areas of B0 inhomogeneity.
8 Physio/Signal1 Card
Minimum TR is recommended to fit the protocol into the
acquisition window. However, the actual TR = # slices * cardiac
cycle * Trigger pulse. Acquisition window is typically chosen to
be smaller than the average cardiac cycle. Trigger pulse is
typically chosen to be one, unless the cardiac cycle is very fast
(PP interval < 800 ms), in which case one may choose to skip
every other pulse (Trigger pulse = 2) for SNR consideration.
9 Sequence/Part 1 Card
Flow comp.: A flow compensated gradient wave form for the
excitation slice selective gradient can be selected to reduce
motion artifacts in b0 image (spoilers in slice direction for
refocusing pulse are also removed) and diffusion weighted images
without b-vector in slice direction.
Multi-slice mode: when physiological triggering is on, single-shot
provides slice-by-slice triggering, while interleaved only triggers on
the first slice.
10 Sequence/Special Card (Ref. CMRR multiband C2P release note)
To enable experimental options, please create a text file
C:\MedCom\MriCustomer\seq\MBAdvancedSettings.ini with the
following contents:
[MultiBand]
RFPulseShape = 1
11 Important Issues (not bugs)
This release will expire on 1 December 2014!
• Multi-slice-multi-angle (MSMA) is not compatible with Siemens
DTI post-processing and mosaic functor. Disable Average ADC
maps, Individual ADC maps, FA maps, Mosaic, and Tensor
when MSMA is used.
• Only diffusion modes “MDDW” and “Free” are compatible with
multi- band. The other modes have been disabled (diffusion
vector in the PRS coordinates can be specified in the external
DiffusionVectors file). The MDDW license is therefore required to
insert the MB diffusion sequence.
12 Known Bugs
• When slice-selective IR or non-selective IR is selected with fat
saturation (fatsat), the order of the IR and fatsat module is
switched from the Siemens default to place IR after fatsat.
However the displayed TI does not reflect this change.
13 Version Changes
Release 002, 3 June 2014 (jgx: vb17a/d2af6b9 | multiband C2P R011)
• UI: RF pulse shape and refocus pulse duration
Release 001, 28 March 2014 (jgx: vb17a/37ca1d6 | multiband C2P R010b)
• Initial public release
14 Acknowledgment
Niels Oesingmann, Ph.D.
Siemens collaboration manager
Icahn School of Medicine at Mount Sinai
product source code, MRA addendum, C2P management
Agus Priatna, Ph.D.
Siemens collaboration manager
Washington University School of Medicine
product source code, MRA addendum
Funding
• Department of Defense (DOD):PC050667
• National Multiple Sclerosis Society (NMSS): FG1782A1
initial IVI implementation
• NIH Human Connectome Project: U54MH091657-01
• NIH NCRR: P41 RR008079
• NIH NIBIB: P41 EB015894
multiband development
• Radiological Society of North America (RSNA): RSCH1328
• TMII and Department of Radiology: Icahn School of Medicine
Capital Campaign
integration of multiband with IVI/rFOV techniques
15

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