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1
Carotid Intima-Media Thickness (CIMT) A
Reproducibility Study Mindy Columbus, Brian
Wagner, Emma Barinas-Mitchell Department of
Epidemiology, University of Pittsburgh,
Pittsburgh, Pennsylvania 15260
Mean Difference -0.045 Mean absolute difference
0.052 Standard Deviation 0.063 Range -0.256
to 0.077 Spearman correlation (r0.93,
plt.0001) ICC (0.02534/0.0282651 0.896)
Introduction

• Statistical Analyses
• Intraclass correlation (ICC) is an estimate of
  the degree of total measurement variability
  caused by between individual variation.
• Certification Reads Tech 1 vs. Tech 2
• Mean Difference 0.015
• Mean absolute difference 0.022
• Standard Deviation 0.024
• Range -0.022 to 0.049

Hypothesis

• Coronary heart disease is the leading cause of
  death in America today, and caused 869,724 deaths
  in 2004.
• Coronary heart disease is caused by
  atherosclerosis, the narrowing of coronary
  arteries due to fatty build ups of plaque.
• CIMT is a well established surrogate marker of
  atherosclerosis and a predictor of cardiovascular
  disease events.
• CIMT is a valid and reproducible measure of
  subclinical cardiovascular disease.
• www.nhlbi.nih.gov
• The Ultrasound Research Lab (URL) in the
  Department of Epidemiology performs subclinical
  cardiovascular disease testing for many NIH
  funded population-based studies.

The null hypothesis is that there is no
difference in CIMT between the Toshiba and
Antares Doppler ultrasound machines.
Results
Conclusion
A five year mean CIMT progression rate of 0.04
mm was estimated based on the literature1. Since
the mean absolute difference was 0.052 mm a
difference in progression may be difficult to
detect, and may in fact appear that the
participants mean CIMT has improved. There was a
difference between the machines, and a presence
of systematic bias illustrated thicker CIMT reads
with the Toshiba machine. This is likely due to
the fact that the Antares scanner produces a
crisper and clearer image demonstrating
advancement of newer digitial technology. Based
on these results, we conclude that the
implementation of newer ultrasound technology may
adversely affect the validity of progression data
for follow-up studies that utilized the older
technology for baseline measurements of CIMT.
References
obs urlid mavga mavgt dmavgat
1 70237 0.57444 0.83000 -0.25556
2 70256 0.68844 0.83469 -0.14625
3 901206 0.67756 0.73613 -0.05856
4 70136 0.62219 0.67969 -0.05750
5 901017 0.89131 0.94500 -0.05369
6 901136 0.60000 0.65069 -0.05069
7 70047 0.56369 0.61381 -0.05012
8 70223 0.55294 0.60088 -0.04794
9 901205 0.48875 0.53581 -0.04706
10 901208 0.52313 0.55294 -0.02981
11 70208 0.62138 0.64950 -0.02812
12 901069 0.63506 0.66281 -0.02775
13 71025 0.55350 0.58038 -0.02687
14 70105 0.76575 0.79213 -0.02638
15 901209 0.49069 0.51500 -0.02431
16 901122 0.49575 0.51600 -0.02025
17 70043 0.96831 0.98056 -0.01225
18 70148 0.86669 0.87731 -0.01062
19 71062 1.03038 1.03925 -0.00887
20 901125 0.90531 0.82863 0.07669

• Chambless, L. et al. Risk Factors for Progression
  of Common Carotid Atherosclerosis The
  Atherosclerosis Risk in Communities Study,
  1987-1998. American Journal of EpidemiologyAmerica
  n Journal of Epidemiology. 200215538-47.
• de Groot E. et al. Measurement of carotid
  intima-media thickness to assess progression and
  regression of atherosclerosis. Natural Clinical
  Practice. Cardiovascular Medicine. 2008
  May5(5)280-8.
• Sekikawa A. et al. Less Subclinical
  Atherosclerosis in Japanese Men in Japan than in
  White Men in the United States in the Post-World
  War II Birth Cohort. American Journal of
  Epidemiology. 2007165617-624.
• Sutton-Tyrrell, K. et al. Measurement Variability
  in Duplex Scan Assessment of Carotid
  Atherosclerosis. Stroke. 1992, 23215-220.
• Thompson, T., Sutton-Tyrrell, K., Wildman, R.
  2001. Continuous Quality Assessment Programs Can
  Improve Carotid Duplex Scan Quality. The Journal
  of Vascular Technology 25(1)33-39.

Methods

• Summary of Training
• Carotid duplex scanning
• Reading carotid scans
• Certification in reading of scans
• Reading for reproducibility study
• Study Design
• Volunteers recruited for carotid duplex scanning
• Tech 1 Certified URL sonographer
• Tech 2 Mindy Columbus

Question
In the Department of Epidemiology Ultrasound
Research Lab (URL), participants of the ERA JUMP
study are returning for a five year follow-up
visit for CIMT measurements to determine
progression rates of subclinical
atherosclerosis.A Toshiba 140A Doppler ultrasound
scanner was used for the baseline measurements,
and the question is whether the follow-up
measurements can be taken on a Siemens Sonoline
Antares Doppler ultrasound scanner in order to
predict progression and not to introduce error
due to differences in machines. .
Acknowledgements
We would like to thank the staff of the
Department of Epidemiology Ultrasound Research
Lab for the training and resources used to
conduct this study.