Free-breathing scans are often desirable in patients who find breath-holding difficult. We present a new approach for free-breathing myocardial strain imaging with displacement-encoding (DENSE) [1]. It acquires images with a single-shot sequence and removes respiratory motion using deformable registration

Bennett, Eric E.

Chefd'Hotel, Christophe

Kellman, Peter

Le, Yuan

Lin, Alex

Lorenz, Christine H.

Wen, Han

English

Yuan Le

Peter Kellman

Eric E Bennett

Alex Lin

Christophe Chefd'Hotel

Christine H Lorenz

Han Wen

Springer - Publisher Connector

BioMed Central
Journal of Cardiovascular Magnetic 
Resonance
ssOpen AcceMeeting abstract
1082 Free-breathing single-shot DENSE myocardial strain 
imaging using deformable registration
Yuan Le*1, Peter Kellman1, Eric E Bennett1, Alex Lin2, 
Christophe Chefd'Hotel3, Christine H Lorenz3 and Han Wen1
Address: 1National Institutes of Health, Bethesda, MD, USA, 2California Institute of Technology, Pasadena, CA, USA and 3SIEMENS, Malvern, PA, 
USA
* Corresponding author    
Introduction
Free-breathing scans are often desirable in patients who
find breath-holding difficult. We present a new approach
for free-breathing myocardial strain imaging with dis-
placement-encoding (DENSE) [1]. It acquires images with
a single-shot sequence and removes respiratory motion
using deformable registration.
Methods
All volunteers (n = 4) were scanned on a 1.5 T Siemens
Avanto scanner. A multi-slice, single-shot DENSE
sequence (Fig. 1) with true-FISP readout (Fig. 2) [2,3] and
FOV-selective excitation [4] was used to acquire 3 short-
axis slices in a heartbeat. Ramped flip-angles through the
readout train equalized the echo amplitudes. Displace-
ment-encoding and image acquisition were placed at end-
systole and late-diastole respectively, in order to capture
the accumulated wall strain of systolic contraction. Imag-
ing parameters were true-FISP echo spacing of 2.5 ms,
matrix size of 128 × 40, FOV of 512 × 120 mm with
restricted excitation (equivalent to a matrix of 128 × 96
with 3/4 phase-encode FOV), slice thickness of 6–8 mm,
and ECG triggering every 2 RR intervals. A data set con-
tained 270 images of 3(slices) × 3(encoding directions) ×
30(repetitions). The encoding directions were oblique
and combined in-plane encoding moments of 4.0 mm/
radian with a through-slice (Z) moment of 1.0 mm/
radian. This Z moment was sufficient to suppress the
unwanted DC and conjugate-echo signal in the single-
shot sequence [4,5]. Each direction was acquired in a sep-
arate heartbeat. The total scan time was 3 – 4 minutes.
Image registration used a deformable algorithm [6]. The
registered images produced 90 strain maps = 3(slices) ×
30(repetitions). These were averaged over the repetitions
to produce average strain maps for the slices. A correlation
threshold was used to remove occasional images of poor
registration quality due to ECG mistrigger.
from 11th Annual SCMR Scientific Sessions
Los Angeles, CA, USA. 1–3 February 2008
Published: 22 October 2008
Journal of Cardiovascular Magnetic Resonance 2008, 10(Suppl 1):A207 doi:10.1186/1532-429X-10-S1-A207
<supplement> <title> <p>Abstracts of the 11<sup>th </sup>Annual SCMR Scientific Sessions - 2008</p> </title> <note>Meeting abstracts – A single PDF containing all abstracts in this Supplement is available <a href="http://www.biomedcentral.com/content/files/pdf/1532-429X-10-s1-full.pdf">here</a>.</note> <url>http://www.biomedcentral.com/content/pdf/1532-429X-10-S1-info.pdf</url> </supplement>
This abstract is available from: http://jcmr-online.com/content/10/S1/A207
© 2008 Le et al; licensee BioMed Central Ltd. 
Time line of left ventricle contraction, ECG and the sequenceF gure 1
Time line of left ventricle contraction, ECG and the 
sequence.Page 1 of 3
(page number not for citation purposes)
Journal of Cardiovascular Magnetic Resonance 2008, 10(Suppl 1):A207 http://jcmr-online.com/content/10/S1/A207To evaluate strain noise reduction by this approach, we
calculated the spatial variance of the pixel-wise strain val-
ues in the LV wall for three processing configurations: 1.
single repetitions without averaging; 2. the average strain
maps; 3. average strain map of respiratory gated (RG) data
by selecting 1/3 of the repetitions with the highest dia-
phragm positions (end expiration).
Results
A typical circumferential strain map from a single repeti-
tion and the corresponding average strain map of all rep-
etitions show marked difference in the noise level (Fig. 3).
The spatial variance of strain decreased from 0.127 to
0.063 from single repetition to the average of the RG
group, and further down to 0.054 upon registration and
Left: Strain map from a single measurement; Right: strain map from the average of all registered imagesFigure 3
Left: Strain map from a single measurement; Right: strain map from the average of all registered images.
True-FISP DENSE sequenceFigure 2
True-FISP DENSE sequence.Page 2 of 3
(page number not for citation purposes)
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averaging of all repetitions. The remaining variance may
account for real variation around the LV.
Conclusion and discussion
Deformable registration of single-shot DENSE images per-
mits averaging over all of the respiratory cycle for noise
reduction. Although the resolution of 4.0 mm is low, the
pixel-wise measurement obviates the need for ROI analy-
sis.
References
1. Aletras AH, et al.: Displacement encoding in cardiac functional
MRI (abstr).  Proc ISMRM 1998, 1:281.
2. Bennett E, et al.: Ultrafast DENSE technique for mapping the
volumetric 3D wall motion of the left ventricle (abstr).  Proc
ISMRM 2002, 10:775.
3. Kim D, et al.: Increasing the SNR and data acquisition effi-
ciency of displacement-encoded MRI by the use of TrueFISP
imaging at 3 T and TSENSE parallel imaging (abstr).  Proc
ISMRM 2006:3597.
4. Aletras AH, et al.: High-resolution strain analysis of the human
heart with fast-DENSE.  JMR 1999, 140(1):41-57.
5. Zhong XD, et al.: Selective suppression of artifact-generating
echoes in cine DENSE using through-plane dephasing.  MRM
2006, 56(5):1126-1131.
6. Hermosillo G, et al.: Variational methods for multimodal image
matching.  IJCV 2002, 50(3):329-343.Page 3 of 3
(page number not for citation purposes)


1082 Free-breathing single-shot DENSE myocardial strain imaging using deformable registration

Caltech Authors - Main

et al.: Displacement encoding in cardiac functional MRI (abstr).

High-resolution strain analysis of the human heart with fast-DENSE. JMR

Increasing the SNR and data acquisition efficiency of displacement-encoded MRI by the use of TrueFISP imaging at 3 T and TSENSE parallel imaging (abstr).

Selective suppression of artifact-generating echoes in cine DENSE using through-plane dephasing. MRM

Ultrafast DENSE technique for mapping the volumetric 3D wall motion of the left ventricle (abstr).

Variational methods for multimodal image matching. IJCV

Variational methods for multimodal image matching. IJCV 2002, 50(3):329-343.yours — you keep the copyright Submit your manuscript here: http://www.biomedcentral.com/info/publishing_adv.asp BioMedcentral Page 3 of 3 (page number not for citation purposes)

https://authors.library.caltech.edu/12153/1/LEYjcmr08.pdf

1082 Free-breathing single-shot DENSE myocardial strain imaging using deformable registration

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