Session Title: Osteoarthritis - Clinical Aspects
Session Type: Abstract Submissions (ACR)
Dynamic contrast enhancement is a powerful tool for highlighting features of a medical image which may not otherwise be seen on “static” scans. While used extensively in other settings, it has not been used until now to study bone marrow lesions (BMLs) in osteoarthritis (OA), lesions which vary over time in volume and change with knee pain.
We studied 23 patients who had patellofemoral (PF) OA. All met ACR criteria for knee OA and were participating in a trial of PF knee braces. All patients had no treatment at baseline, were on brace at 12 weeks and acquired MRI’s with a gadolinium(Gd)-enhanced dynamic image sequence at both times.
Within these knees, 40 PF or femoral BMLs were manually segmented at baseline and 12 weeks on sagittal Gd-enhanced images (TR 500ms, TE 17ms, FoV 16cm, 384×384). Knee osteoarthritis outcome score (KOOS) pain data was collected at each time.
We assessed dynamic parameters within BMLs in two steps: (1) transforming the segmented BML from the sagittal sequence to the axial dynamic sequence (TR 5.4ms, TE 1.9ms, FoV 14cm, 256×256); (2) using the extended Kety model (Tofts 1997) to calculate the parameters ve (fractional extracellular volume), vp (fractional blood plasma volume) and Ktrans (transfer coefficient from vp to ve:a direct measure of perfusion) at each voxel. The mean of each parameter was calculated for each BML (one to three per patient), taking care to ensure that this was done consistently between the baseline and 12 week images. The distribution of Ktrans within the BMLs was heterogeneous and limited to small volumes, so to avoid averaging of diverse values, we examined peak Ktrans value in the BML also. To compare with KOOS, mean parameters and peak Ktrans value were examined across all BMLs within a knee.
To evaluate the relation of the parameters to BML volumes and KOOS, we calculated Spearman rank correlation coefficients.
After 12 weeks, change in mean values of the parameters Ktrans, ve and vp did not correlate either with change in volume of the BML (Ktrans: r=0.02; ve: r=-0.07; vp: r=0.02) or change in KOOS (Ktrans: r=0.18; ve: r=0.03; vp: r=0.09). Change in the peak value of Ktrans correlated better with change in volume of the BML (r=0.43: p=0.0056, see figure) but not with KOOS (r=-0.11).
There are no clear correlations between the means of the parameters Ktrans, ve and vp and change in BML volume or KOOS. The peak Ktrans value of a BML may be related to its likelihood of undergoing change.
A. D. Gait,
T. F. Cootes,
E. J. Marjanovic,
M. J. Parkes,
C. E. Hutchinson,
D. T. Felson,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/bone-marrow-lesions-in-knees-with-osteoarthritis-can-parameters-from-dynamic-contrast-enhancement-predict-change-in-bone-marrow-lesion-volume-or-knee-pain-change/