Additional standardized measurements and interpretations of OAI images from selected samples of participants are available to registered users of OAI Online. Once again, the primary focuses of these assessments are longitudinal structural outcomes of osteoarthritis, and include readings that have up to four time points.

These central images assessments include the following:

• Quantitative cartilage and bone morphology from longitudinal sets of knee MRIs (baseline; 12-month; 24-month; 48-month; progression cohort subset).
• Semi-quantitative (K-L grade, JSN, other IRFs) readings from longitudinal sets of knee X-rays. These X-rays were previously read and now have been re-read for reliability (baseline; 12-month; 24-month; 36-month; progression cohort subset).
• Quantitative joint space width readings from longitudinal sets of knee X-rays. Some of these X-rays were previously read and now have been re-read for reliability (baseline; 12-month; 24-month; progression cohort subset and a subset of non-exposed controls).

The image assessments can be downloaded from the OAI Online website (https://oai.epi-ucsf.org/datarelease/). Please refer to Data News on the OAI Online home page for the latest details about this and previous releases.