Accuracy and test-retest precision of quantitative cartilage morphology on a 1.0 T peripheral magnetic resonance imaging system.

OBJECTIVE: Quantitative magnetic resonance imaging (qMRI) of knee cartilage morphology is a powerful research tool but relies on expensive and often inaccessible 1.5 T whole-body equipment. Here we examine the reproducibility and accuracy of qMRI at 1.0 T by direct comparison with previously validated technology.
METHODS: Coronal images of the knee were obtained in six healthy and six osteoarthritic participants. Two data sets were acquired with a 1.5T whole-body magnetic resonance imaging (MRI) system and two with a 1.0 T peripheral MRI system, with repositioning between scans. Proprietary software was used to analyze surface area, volume, and thickness of femoral and tibial cartilage.
RESULTS: At 1.0 T, precision errors for surface areas (root-mean-square (RMS) coefficient of variation (CV%)=1.7-2.6%) were higher than those at 1.5 T (1.0-2.1%). For volume and thickness, precision errors were 2.9-5.5% at 1.0 T compared to 1.6-3.4% at 1.5 T. High levels of agreement were found between the two scanners over all plates. With the exception of lateral femoral cartilage (volume and thickness), no statistically significant systematic bias was found between 1.0 T and 1.5 T.
CONCLUSIONS: This is the first reported study to show that knee cartilage morphology can be determined with a reasonable degree of accuracy and precision using a 1.0 T peripheral scanner. Peripheral MRI is less costly, can be performed in clinical offices, and is associated with higher patient comfort and tolerance than 1.5 T whole-body MRI. Implementation of qMRI with peripheral systems may thus permit its more widespread use in clinical research and patient care.