Elsevier

Osteoarthritis and Cartilage

Volume 14, Issue 11, November 2006, Pages 1091-1097
Osteoarthritis and Cartilage

dGEMRIC as a function of BMI1

https://doi.org/10.1016/j.joca.2006.05.007Get rights and content
Under an Elsevier user license
open archive

Summary

Objective

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) reflects cartilage glycosaminoglycan (GAG) distribution. The technique assumes that the plasma levels of the contrast agent Gd-DTPA2− are the same across individuals after intravenous (IV) injection, when dosing by weight. However, adipose tissue has lower extracellular water (ECW) than lean tissue. The aims of this study were to measure (1) plasma Gd-DTPA2− levels vs body mass index (BMI), and (2) dGEMRIC vs BMI after correcting for the dose–BMI effect.

Method

(1) Plasma Gd-DTPA2− levels were analyzed at 3–90 min after IV injection per body weight in 24 individuals with BMI between 21.5 and 46.5. (2) dGEMRIC was compared with BMI in 19 asymptomatic volunteers and 23 with osteoarthritis (OA).

Results

(1) Plasma Gd-DTPA2− kinetics were similar in obese and non-obese groups, however, overall concentration was higher in the obese group. A very obese subject (BMI 45) would have 1.4 times higher Gd-DTPA2− concentration than a lean subject (BMI 20), which translates into a bias in dGEMRIC of up to 20%. (2) With dose bias taken into account, dGEMRIC showed no correlation with BMI in asymptomatic knees. In OA knees, unnarrowed femoral compartments demonstrated a negative correlation between dGEMRIC and BMI (R = 0.57, P = 0.004). No correlation was seen in radiographically narrowed compartments.

Conclusion

BMI can be a source of dosing bias in dGEMRIC and a correction factor should be considered in cross-sectional studies with a large range of BMI. There is no correlation between dGEMRIC and BMI in asymptomatic knees, but a negative correlation in OA knees.

Key words

Cartilage
Articular/pathology
Gadolinium DTPA
Glycosaminoglycans
MR Imaging/diagnosis
Osteoarthritis
Body mass index
Proteoglycans

Cited by (0)

1

This work was supported by the NIH Grant AR42773 and a Biomarker grant from the Arthritis Foundation.