. Author manuscript; available in PMC: 2019 Apr 11.

Published in final edited form as: Nat Rev Rheumatol. 2012 Jul 10;8(10):622–630. doi: 10.1038/nrrheum.2012.113

Table 3 |.

OAI image analysis completed to date^* and available for public use¹

Imaging technique	Measurements	Approximate sample size (knees)	Timepoints
*Knee radiography*
Fixed flexion radiography	KLG, individual features (OARSI grades)	4,200 (8,400)	0, 12, 24, 36, and 48 months
Fixed flexion radiography	Quantitative JSW (minimum, fixed location)	2,835 (5,095)	0, 12, 24, 36, and 48 months
*Knee MRI*
Various sequences	Femorotibial cartilage volume, thickness, etc.	702 (732)	0, 12, and 24 months^‡
Sagittal DESS	Femorotibial cartilage volume, thickness, etc.	590 (600)	0, 12, and 24 months^‡
Sagittal DESS	Femorotibial cartilage volume, thickness, etc.	85 (86); subset of sample above	0, 12, 24, and 48 months^‡

Image analysis is ongoing in several larger projects (for example, in ancillary studies) and more data will be released in the future.

^‡

Some knees do not have 12-month follow-up data, but all have 24-month follow-up data. Abbreviations: DESS, double echo at steady state; JSW, joint-space width; KLG, Kellgren–Lawrence grade; OA, osteoarthritis; OAI, OA Initiative; OARSI, OA Research Society International.