Alistair Young

Andreas Greiser

Brett R Cowan

Mariappan S Nadar

Michaela Schmidt

Suzanne Lydiard

Journal of Cardiovascular Magnetic Resonance

PubMed

Springer - Publisher Connector

WORKSHOP PRESENTATION Open Access
Inter-observer variability of LV mass and volumes
with compressed sensing
Suzanne Lydiard1, Andreas Greiser2, Michaela Schmidt2, Mariappan S Nadar3, Brett R Cowan1*, Alistair Young1
From 17th Annual SCMR Scientific Sessions
New Orleans, LA, USA. 16-19 January 2014
Background
Recently developed compressed sensing (CS) SSFP
sequences significantly reduce data acquisition time
thereby reducing patient breath-hold and scan time rela-
tive to standard techniques. The variability of ventricular
functional (VF) analysis of CS data is not known so this
study investigated the inter-observer variation of left
ventricular (LV) mass and volume measurements com-
pared to standard SSFP acquisitions.
Methods
Twenty healthy human subjects (9 male, 40 ± 14 years)
underwent LV SSFP imaging on a MAGNETOM Skyra
3T scanner (Siemens, Germany). Three sequences were
acquired (i) gold standard fully sampled SSFP (FULL)
and two 2D prototype sequences featuring CS recon-
struction and regularisation in space and time with
acceleration factors (ii) R = 4 (R4) or (iii) R = 9.2 (R9.2).
5-8 short axis slices (thickness 6 mm, slice gap 9 mm)
and three long axis slices (4-,3-,2-chamber), FOV= 260-
340 mm, were acquired for each sequence. FULL images
were acquired over 14 heart-beats with TE = 1.54 ms,
a = 51°, 25 frames, matrix 256 × 256 and iPAT factor 2.
R4 images were acquired over 4 beats with TE = 1.29
ms, a = 41°, 21 frames, matrix 192 × 143 with iPAT.
R9.2 images were acquired over 2 beats (one dummy
beat for steady state preparation, thereby representing
‘realtime’ acquisition) with TE = 1.27 ms, a = 42°,
19frames, matrix 192 × 129. Images were reconstructed
on-line using a non-linear iterative CS method with k-t
regularisation derived from a SENSE type reconstruction
[1]. LV function parameters were calculated by two ana-
lysts using CIM Version 7, blinded by sequence type
and participant. The percentage differences between the
two analysts’ results were calculated to give an indica-
tion of inter-observer variability.
Results
The average of both analysts’ measurements over all
participants for the FULL acquisition were: end-diastolic
volume (EDV) = 14.6 mL, end-systolic volume (ESV) =
56.9 mL, ejection fraction (EF) = 61.4 mL and LV mass
(LVM) = 113.9 g. The mean difference (bias) between
the analysts is provided in table 1 and show a similar
trend for all acquisitions likely related to the preference
of each analyst for the positioning the endocardial and
1Auckland MRI Research Group, University of Auckland, Auckland, New
Zealand
Full list of author information is available at the end of the article
Table 1 Inter-observer percentage differences (± standard deviation) for ventricular function measurements for CS
acceleration.
EDV ESV EF Mass
Inter-observer % Diff Inter-observer % Diff Inter-observer % Diff Inter-observer % Diff
FULL 2.1 ± 2.8* 2.5 ± 6.0** -0.4 ± 3.9* -8.9 ± 3.5**
R4 1.3 ± 2.6* 3.3 ± 5.6* -1.5 ± 3.6 -8.9 ± 5.8**
R9.2 1.7 ± 3.3* 6.0 ± 5.5* -3.8 ± 4.2 -8.7 ± 5.7**
p values represent repeated measures Bonferoni corrected ANOVA, * represents 0.05 < p < 0.01, ** represents p < 0.01
Lydiard et al. Journal of Cardiovascular Magnetic
Resonance 2014, 16(Suppl 1):W37
http://www.jcmr-online.com/content/16/S1/W37
© 2014 Lydiard 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. The Creative Commons Public Domain Dedication waiver (http://
creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
epicardial contours. While there were significant differ-
ences (p < 0.05) in all but EF for the CS sequences,
these were of a comparable magnitude across all three
sequence types. This suggests the bias is related primarily
to the analyst rather than the accelerated CS acquisitions.
Conclusions
The inter-observer variability of LV function for CS data
was comparable to that for standard acquisitions. Inter-
observer variability of VF was not generally increased
when CS was applied to SSFP cine analysis
Funding
Siemens Medical Systems.
Authors’ details
1Auckland MRI Research Group, University of Auckland, Auckland, New
Zealand. 2Healthcare Sector, Siemens AG, Erlangen, Germany. 3Siemens
Corporate Technology, Princeton, New Jersey, USA.
Published: 16 January 2014
Reference
1. Beck A: SIIMS 2009, 2:183.
doi:10.1186/1532-429X-16-S1-W37
Cite this article as: Lydiard et al.: Inter-observer variability of LV mass
and volumes with compressed sensing. Journal of Cardiovascular
Magnetic Resonance 2014 16(Suppl 1):W37.
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Figure 1 Bland-Altman analysis of EDV (top row) and Mass (bottom row) comparing the two analysts for FULL (left), R4 (middle) and
R9.2 (right) sequences.
Lydiard et al. Journal of Cardiovascular Magnetic
Resonance 2014, 16(Suppl 1):W37
http://www.jcmr-online.com/content/16/S1/W37
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Inter-observer variability of LV mass and volumes with compressed sensing

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Inter-observer variability of LV mass and volumes with compressed sensing

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