Shear Wave Elastography for Liver Stiffness
Measurement in Clinical Sonographic Examinations
Evaluation of Intraobserver
Reproducibility, Technical Failure, and Unreliable Stiffness Measurements
Objectives—The purpose of
this study was to determine the optimal minimum number of liver stiffness
measurements on shear wave elastography (SWE) and to evaluate the frequency of
technical failures and unreliable stiffness measurements and the intraobserver
reproducibility of SWE.
Methods—This
retrospective study was approved by our Institutional Review Board, and
informed consent was waived. From August 2011 to January 2013, 540 patients
underwent abdominal sonography, including SWE. In 86 patients (group 1), the minimum
number of examinations was determined by comparing the intraclass correlation
coefficient (ICC) of subsets of the first 2 to 14 measurements with that from
15 measurements. In 454 patients (group 2), 2 SWE sessions were performed in
the right lobe within 1 day. Technical failure was defined as when no or little
signal was obtained in the elastogram during the first 5 acquisitions;
unreliable SWE results were defined as when the interquartile range/median
liver stiffness value exceeded 30%. Intraobserver reproducibility was assessed
using ICCs and Bland-Altman plots.
Results—In group 1, the
ICCs did not significantly increase after the first 6 measurements. In group 2,
there were technical failures and unreliable results in 47 patients (10.35%)
and 74 patients (16.29%), respectively. In 407 patients, after excluding
technical failures, there was no significant difference in the median liver
stiffness values between the 2 sessions (6.95 versus 6.86 kPa; P > .05). The
overall intraobserver reproducibility was excellent (ICC, 0.95).
Conclusions—In this study,
the optimal minimum number of SWE measurements was 6, and SWE using 6
measurements showed excellent intraobserver reproducibility.
o Received March 28, 2013.
o Revision
received May 6, 2013.
o Accepted June 27, 2013.
o © 2014 by the
American Institute of Ultrasound in Medicine
Real-time Ultrasound Elastography for
Differentiation of Benign and Malignant Thyroid Nodules
A Meta-analysis
Objectives—The clinical
challenge of managing thyroid nodules nowadays is to diagnose the minority of
malignant disease. Real-time ultrasound elastography, which can measure tissue
elasticity, is used as a complement to conventional sonography for improving
the diagnosis of thyroid tumors. There are 2 common criteria for evaluating an
elastogram: the elasticity score and strain ratio. This meta-analysis was
performed to expand on a previous meta-analysis to assess the diagnostic power
of ultrasound elastography in differentiating benign and malignant thyroid
nodules for elasticity score and strain ratio assessment.
Methods—The MEDLINE,
EMBASE, PubMed, and Cochrane Library databases up to January 31, 2013, were
searched. The pooled sensitivity, specificity, and summary receiver operating
characteristic curve were obtained from individual studies with a
random-effects model. The extent and sources of heterogeneity were explored.
Results—A total of 5481
nodules in 4468 patients for elasticity score studies and 1063 nodules in 983
patients for strain ratio studies were analyzed. The overall mean sensitivity
and specificity of ultrasound elastography for differentiation of thyroid
nodules were 0.79 (95% confidence interval [CI], 0.77–0.81) and 0.77 (95% CI,
0.76–0.79) for elasticity score assessment and 0.85 (95% CI, 0.81–0.89) and
0.80 (95% CI, 0.77–0.83) for strain ratio assessment, respectively. The areas
under the curve for the elasticity score and strain ratio were 0.8941 and
0.9285.
Conclusions—These results
confirmed those obtained in the previous meta-analysis. Ultrasound elastography
has high sensitivity and specificity for identification of thyroid nodules. It
is a promising tool for reducing unnecessary fine-needle-aspiration biopsy.
o Received March 20, 2013.
o Revision
received May 14, 2013.
o Accepted July 13, 2013.
o © 2014 by the
American Institute of Ultrasound in Medicine
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