Multiparametric quantitative MRI in knee osteoarthritis: evidence and requirements for interpretation and reporting

Quantitative MRI can characterize cartilage and other joint tissues beyond visible structural damage, but its contribution to individual management of knee osteoarthritis remains uncertain. This narrative review examines the evidence needed to interpret quantitative measurements, combine parameters, and report their uncertainty. An initial PubMed search in June 2026 was supplemented on 14 September 2026 by an updated PubMed search and broader Embase and Web of Science searches. Targeted full-text assessment addressed incremental value, outcome timing, validation, and measurement error. Selected development studies found better discrimination with integrated diffusion and relaxation measurements than with individual parameters, whereas other combined imaging models did not improve on simpler comparators. Longitudinal associations were outcome-specific, and independent external validation was limited. Treatment studies showed inconsistent agreement between imaging changes and symptomatic benefit. We propose a five-step interpretation framework that establishes the clinical question, verifies technical adequacy, assesses morphology and comparable reference data, evaluates measurement uncertainty, and separates observations from clinical inferences. Two hypothetical scenarios illustrate its application. Quantitative MRI currently provides its strongest support as a controlled research measurement. Demonstrated reproducibility, an appropriate comparator, and evidence of added decision value are required before a quantitative finding can justify patient-level diagnostic, prognostic, or treatment-response claims.