MRI T2 and T1\u03c1 relaxation in patients at risk for knee osteoarthritis: a systematic review and meta-analysis

Hayden F Atkinson,Jonathan D Thiessen,R Terry Thompson,Rebecca F Moyer,Lauren E Kanko,Dianne M Bryant,Daniel Yacoub,Trevor B Birmingham

doi:10.1186/s12891-019-2547-7

Abstract

BackgroundMagnetic resonance imaging (MRI) T2 and T1ρ relaxation are increasingly being proposed as imaging biomarkers potentially capable of detecting biochemical changes in articular cartilage before structural changes are evident. We aimed to: 1) summarize MRI methods of published studies investigating T2 and T1ρ relaxation time in participants at risk for but without radiographic knee OA; and 2) compare T2 and T1ρ relaxation between participants at-risk for knee OA and healthy controls.MethodsWe conducted a systematic review of studies reporting T2 and T1ρ relaxation data that included both participants at risk for knee OA and healthy controls. Participant characteristics, MRI methodology, and T1ρ and T2 relaxation data were extracted. Standardized mean differences (SMDs) were calculated within each study. Pooled effect sizes were then calculated for six commonly segmented knee compartments.Results55 articles met eligibility criteria. There was considerable variability between scanners, coils, software, scanning protocols, pulse sequences, and post-processing. Moderate risk of bias due to lack of blinding was common. Pooled effect sizes indicated participants at risk for knee OA had lengthened T2 relaxation time in all compartments (SMDs from 0.33 to 0.74; p < 0.01) and lengthened T1ρ relaxation time in the femoral compartments (SMD from 0.35 to 0.40; p < 0.001).ConclusionsT2 and T1ρ relaxation distinguish participants at risk for knee OA from healthy controls. Greater standardization of MRI methods is both warranted and required for progress towards biomarker validation.

Highlights

Magnetic resonance imaging (MRI) T2 and T1ρ relaxation are increasingly being proposed as imaging biomarkers potentially capable of detecting biochemical changes in articular cartilage before structural changes are evident
Articles included in the systematic review but excluded from the meta-analysis either examined incomparable regions of interest (ROI), or had insufficient data to be included in the meta-analyses [54, 66, 68, 69, 77, 85, 89, 90]
Standardized mean difference (SMD) = standardized mean difference, 95% CI = 95% confidence interval, ACL = anterior cruciate ligament, PCL = posterior cruciate ligament, ICRS=International Cartilage Repair Society, OAI=Osteoarthritis Initiative, OA = osteoarthritis, GE = General Electric, T = Tesla. b Forest plots illustrating individual and pooled SMD for differences in T1rho and T2 relaxation time of medial tibial articular cartilage between healthy controls and participants at risk for knee OA

Summary

Introduction

Magnetic resonance imaging (MRI) T2 and T1ρ relaxation are increasingly being proposed as imaging biomarkers potentially capable of detecting biochemical changes in articular cartilage before structural changes are evident. T2 and T1ρ relaxation have engendered considerable interest as a potential biomarkers for knee OA [17], especially given their proposed ability to detect biochemical changes in articular cartilage before structural changes are evident [15, 18, 19] If these measures can detect compromised articular cartilage prior to radiographic evidence of OA, they may have the potential to serve as an outcome measure in early intervention studies targeting at-risk populations, such as people with knee anterior cruciate ligament (ACL) rupture [20,21,22], meniscal injuries [23, 24], or obesity [25, 26]. There is abundant evidence suggesting T2 and T1ρ relaxation times are prolonged in knees with established radiographic OA compared to healthy knees [27, 28], the ability to detect changes between knees at risk for OA and healthy knees is less clear

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