Bonanno, Gabriele

Coppo, Simone

Feliciano, Hélène

Lauriers, Nathalie

Locca, Didier

Schwitter, Juerg

Stuber, Matthias

Van Heeswijk, Ruud B

English

PubMed

Ruud B Van Heeswijk

Hélène Feliciano

Gabriele Bonanno

Simone Coppo

Nathalie Lauriers

Didier Locca

Juerg Schwitter

Matthias Stuber

Springer - Publisher Connector

ORAL PRESENTATION Open Access
Quantitative free-breathing 3T T2-mapping of the
heart designed for longitudinal studies
Ruud B Van Heeswijk1,2*, Hélène Feliciano1,2, Gabriele Bonanno1,2, Simone Coppo1,2, Nathalie Lauriers3,
Didier Locca3, Juerg Schwitter3, Matthias Stuber1,2
From 15th Annual SCMR Scientific Sessions
Orlando, FL, USA. 2-5 February 2012
Background
Recently, T2-weighted MRI for the characterization of
edema after myocardial infarction has attracted consid-
erable attention (Friedrich, NatRevCardiol2010).
Furthermore, the recently proposed combination of
bSSFP imaging and T2Prep for T2-mapping at 1.5T has
enabled a rapid quantitative cardiac T2 estimation
(Huang et al., MRM2007). However, the accuracy of this
method may still be limited due to the complex T2/T1
signal weighting. Especially for longitudinal studies
designed for monitoring and/or guiding therapy, accu-
rate and reproducible T2 measurements will be critical.
A novel quantitative 3T T2-mapping protocol was there-
fore developed and tested in both healthy volunteers
and patients.
Methods
An adiabatic T2prep with 3 incremental TE values,
affine coregistration, a navigator and 2D radial gradient
echo imaging were combined for free-breathing T2-map-
ping at 3T with a spatial resolution of 1.25mm. Bloch
equation simulations of this sequence were used to opti-
mize scan parameters and to determine an empirical
equation that compensates for T1 relaxation and which
returns the “true” T2. The T2-mapping sequence and
empirical equation were then validated in a series of 15
phantoms in which the true T2 was determined with a
9-TE spin-echo sequence. Next, the myocardial short
axis T2 of 8 healthy volunteers was mapped in two dif-
ferent scan sessions while a reference phantom (T2=43.1
±0.7ms) was placed next to the thorax. The average
myocardial T2 for both sessions was computed with and
without correction with the “true” reference phantom
T2. Finally, this validated protocol was used in 5 patients
in the subacute phase after revascularization of acute
ST-elevation myocardial infarctions and compared to
T2-weighted TSE imaging.
Results
As a result of both the simulations and phantom scans,
optimized sequence parameters included: TET2prep=60/
30/0ms, TRR=3 heartbeats, TR/TE=5.3/2.4ms. The
empirical equation to determine T2 was S=S0[exp
(-TET2prep/T2)+0.06], where S and S0 are the measured
and steady-state signal (Fig. 1a). Scans of the phantoms
with known T2 confirmed a 12±2%(p<0.001) improve-
ment in T2 estimation with the empirical equation as
compared to the standard T2 decay measurements (Fig.
1b). The myocardial T2 in the volunteers was homoge-
neous (42±5ms over all volunteers) and on average
showed a 5±2% difference between the two scan ses-
sions. When compensated with the T2 from the refer-
ence phantom, this difference decreased to 2±1%
(p=0.02). In all patients, T2maps could successfully be
obtained and a clear demarcation of zones with elevated
T2 values was consistent with the findings on T2-
weighted MRI and X-ray coronary angiography as
shown in the example in Fig. 2.
Conclusions
The methodology presented in this study enables robust
and accurate cardiac T2-mapping at 3T, while the addi-
tion of a reference phantom improves reproducibility.
Therefore, it may be well-suited for longitudinal studies
in patients with ischemic heart disease.
Funding
N/A.
1Radiology, University Hospital Lausanne (CHUV), Lausanne, Switzerland
Full list of author information is available at the end of the article
Van Heeswijk et al. Journal of Cardiovascular Magnetic Resonance 2012, 14(Suppl 1):O51
http://www.jcmr-online.com/content/14/S1/O51
© 2012 Van Heeswijk et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Author details
1Radiology, University Hospital Lausanne (CHUV), Lausanne, Switzerland.
2Center for BioMedical Imaging (CIBM), Lausanne, Switzerland. 3Center for
Cardiac Magnetic Resonance and Cardiology Service, University Hospital
Lausanne (CHUV), Lausanne, Switzerland.
Published: 1 February 2012
doi:10.1186/1532-429X-14-S1-O51
Cite this article as: Van Heeswijk et al.: Quantitative free-breathing 3T
T2-mapping of the heart designed for longitudinal studies. Journal of
Cardiovascular Magnetic Resonance 2012 14(Suppl 1):O51.
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Figure 1 Single pixel T2-mapping in a simulation and phantom scan. A) Simulated magnetization (black dots) for myocardium with input
T2=45ms at the T2prep times (60, 30 and 0ms) and fitted curves with the standard (dashed line) and new, empirical (whole line) equation. The
new equation leads to more accurate T2 computations. B) Similar results are obtained in a pixel in a T2map of a phantom where the T2 was
determined to be 45ms with a 9-TE spin echo scan.
Figure 2 Short-axis T2map together with conventional T2-weighted turbo spin-echo and X-ray coronary angiogram in a patient with a
myocardial infarct. A) A clearly demarcated zone with elevated T2 can be seen in the region of the black arrow, which might indicate
myocardial edema. The non-infarcted tissue has a homogenous T2, while the reference phantom adjacent to the thorax appears homogeneous
with T2 values similar to those in healthy tissue. B) The conventional T2-weighted TSE image confirms the elevated T2 in the region of the infarct
(arrow). C) Consistent with these findings, the x-ray coronary angiogram shows a severe stenosis in an obtuse marginal artery (arrow).
Van Heeswijk et al. Journal of Cardiovascular Magnetic Resonance 2012, 14(Suppl 1):O51
http://www.jcmr-online.com/content/14/S1/O51
Page 2 of 2


Quantitative free-breathing 3T T2-mapping of the heart designed for longitudinal studies

Van Heeswijk Ruud B

Feliciano Hélène

Bonanno Gabriele

Coppo Simone

Lauriers Nathalie

Locca Didier

Schwitter Juerg

Stuber Matthias

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Journal of Cardiovascular Magnetic Resonance

Quantitative free-breathing 3T T<sub>2</sub>-mapping of the heart designed for longitudinal studies

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Quantitative free-breathing 3T T2-mapping of the heart designed for longitudinal studies

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