Elsevier

Osteoarthritis and Cartilage

Volume 16, Issue 9, September 2008, Pages 994-1004
Osteoarthritis and Cartilage

The osteoarthritis initiative (OAI) magnetic resonance imaging quality assurance methods and results

https://doi.org/10.1016/j.joca.2008.02.010Get rights and content
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Summary

Objective

To outline the osteoarthritis initiative's (OAI) magnetic resonance (MR) system quality assurance (QA) processes and present the first 3 years' results.

Method

OAI MR QA included acquisitions evaluated manually at each of the four sites and other acquisitions assessed by an automated computer program. Key image characteristics such as signal-to-noise, contrast-to-noise, signal uniformity, T2 relaxation times, local and global geometric distortion were quantified monthly using the automated program.

Results

Uniformly high quality, artifact-free subject images were obtained from all four OAI 3 tesla MR facilities. Over a 3-year period, key criteria for quantitative cartilage morphometry were excellent with a 190.0 mm diameter and 148.0 mm length object having reproducible diameter (0.04% RMS CV) and length (0.56% RMS CV). This resulted in spherical volume reproducibility of 0.46% RMS CV. Ghost levels were consistently <0.2%. T2 relaxation time varied longitudinally site-by-site from 2.3 to 18.8% RMS CV. All other measures of MR system stability were met except: 3.0 mm and 5.0 mm slice thicknesses were consistently larger than expected; knee coil signal uniformity and signal level varied significantly over time.

Conclusions

OAI MR QA results compared favorably to prior publications and identified similar technical issues for geometric measurements. The longitudinal variations measured in the OAI QA process should have minimal impact on the accuracy and reproducibility of cartilage thickness and volume quantification. This stability should enable direct comparison of baseline and follow-up images. Cross-comparison of the results from all four OAI sites reveals that the MR systems are sufficiently uniform to enable results to be combined.

Key words

Magnetic resonance, MR
Quality assurance, QA
Clinical trial

Abbreviations

CNR
contrast-to-noise ratio
CV
coefficient of variation
DESS
dual echo steady state
FLASH
fast low-angle shot
FOV
field-of-view
GRE
gradient-echo
IW
intermediate-weighted
MR
magnetic resonance
MSME
multi-slice, multi-echo
QA
quality assurance
PD
proton density weighted
RMS
root mean square
SE
spin echo
SNR
signal-to-noise ratio
T
tesla
T1W1
T1-weighted
T2W
T2-weighted
TE
echo time
TR
repetition time
TSE
turbo spin echo
WE
water excitation

Cited by (0)

a

Current address: The Warren Alpert Medical School of Brown University, Providence, RI, USA.