Evaluation of the relationship between T1ρ and T2 values and patella cartilage degeneration in patients of the same age group

Enabling early detection of knee osteoarthritis using diffusion-relaxation correlation spectrum imaging

AIM

To present a technique that enables detection of early stage OA of the knee using diffusion-relaxation correlation spectrum imaging (DR-CSI).

MATERIALS AND METHODS

Fifty-five early osteoarthritis patients (OA, Kellgren-Lawrence [KL] score 1 to 2; mean age, 56.4 years) and 49 healthy volunteers (mean age, 56.7 years) were underwent magnetic resonance imaging (MRI) with T2-mapping and DR-CSI techniques. Maps of mean apparent diffusion coefficient (ADC), T2 relaxation time and volume fraction Vi for DR-CSI compartment i (A, B, C, D) sensitivity, specificity, and positive and negative likelihood ratio (PLR, NLR) were assessed to determine the diagnostic accuracy for detection of early-stage degeneration of knee articular cartilage. The structural abnormalities of articular cartilage were evaluated using modified Whole-Organ MR Imaging Scores (WORMS).

RESULTS

All intra- and interobserver agreements for DR-CSI compartment volume fractions and modified WORMS of cartilage were excellent. Early OA versus the controls had higher V_C, lower V_A and V_B (p<0.001), but comparable V_D (p>0.05). V_A, V_B and V_C had a moderate association with WORMS. No significant correlation was identified between V_D and WORMS. V_C had better ability than V_A,V_B, V_D, T2 and ADC to discriminate early OA patients from healthy controls (area under the curve, 0.898). Sensitivity, specificity, PLR, and NLR of V_C with a cut-off value of 29.9% were 81.8% (95% confidence interval [CI], 69.1-90.9%), 95.9% (86-99.5%), 20.05% (5.13-78.34%), and 0.19% (0.11-0.33%).

CONCLUSIONS

DR-CSI compartment volume fractions may be sensitive indicators for detecting early-stage degeneration in knee articular cartilage.

Patellar instability MRI measurements are associated with knee joint degeneration after reconstruction of the medial patellofemoral ligament

OBJECTIVE

To qualitatively and quantitatively evaluate the 2-year magnetic resonance imaging (MRI) outcome after MPFL reconstruction at the knee and to assess MRI-based risk factors that predispose for inferior clinical and imaging outcomes.

MATERIALS AND METHODS

A total of 31 patients with MPFL reconstruction were included (22 ± 6 years, 10 female). MRI was performed preoperatively in 21/31 patients. Two-year follow-up MRI included quantitative cartilage T2 and T1rho relaxation time measurements at the ipsilateral and contralateral knee. T2_relative was calculated as T2_{patellofemoral}/T2_femorotibial. Morphological evaluation was conducted via WORMS scores. Patellar instability parameters and clinical scores were obtained. Statistical analyses included descriptive statistics, t-tests, multivariate regression models, and correlation analyses.

RESULTS

Two years after MPFL reconstruction, all patellae were clinically stable. Mean total WORMS scores improved significantly from baseline to follow-up (mean difference ± SEM, - 4.0 ± 1.3; P = 0.005). As compared to patients with no worsening of WORMS subscores over time (n = 5), patients with worsening of any WORMS subscore (n = 16) had lower trochlear depth, lower facetal ratio, higher tibial-tuberosity to trochlear groove (TTTG) distance, and higher postoperative lateral patellar tilt (P < 0.05). T2_relative was higher at the ipsilateral knee (P = 0.010). T2_relative was associated with preoperatively higher patellar tilt (P = 0.021) and higher TTTG distance (P = 0.034). TTTG distance, global T2 values, and WORMS progression correlated with clinical outcomes (P < 0.05).

CONCLUSION

MPFL reconstruction is an optimal treatment strategy to restore patellar stability. Still, progressive knee joint degeneration and patellofemoral cartilage matrix degeneration may be observed, with patellar instability MRI parameters representing particular risk factors.

A New Method for Cartilage Evaluation in Femoroacetabular Impingement Using Quantitative T2 Magnetic Resonance Imaging: Preliminary Validation against Arthroscopic Findings

OBJECTIVE

The outcome of arthroscopic treatment for femoroacetabular impingement (FAI) depends on the preoperative status of the hip cartilage. Quantitative T2 can detect early biochemical cartilage changes, but its routine implementation is challenging. Furthermore, intrinsic T2 variability between patients makes it difficult to define a threshold to identify cartilage lesions. To address this, we propose a normalized T2-index as a new method to evaluate cartilage in FAI.

DESIGN

We retrospectively analyzed magnetic resonance imaging (MRI) data of 18 FAI patients with arthroscopically confirmed cartilage defects. Cartilage T2 maps were reconstructed from multi-spin-echo 3-T data using the echo-modulation-curve (EMC) model-based technique. The central femoral cartilage, assumed healthy in early-stage FAI, was used as the normalization reference to define a T2-index. We investigated the ability of the T2-index to detect surgically confirmed cartilage lesions.

RESULTS

The average T2-index was 1.14 ± 0.1 and 1.13 ± 0.1 for 2 separated segmentations. Using T2-index >1 as the threshold for damaged cartilage, accuracy was 88% and 100% for the 2 segmentations. We found moderate intraobserver repeatability, although separate segmentations yielded comparable accuracy. Damaged cartilage could not be identified using nonnormalized average T2 values.

CONCLUSIONS

This preliminary study confirms the importance of normalizing T2 values to account for interpatient variability and suggests that the T2-index is a promising biomarker for the detection of cartilage lesions in FAI. Future work is needed to confirm that combining T2-index with morphologic MRI and other quantitative biomarkers could improve cartilage assessment in FAI.

Chinese primary knee osteoarthritis progression cohort (CPKOPC) to evaluate the progression of knee osteoarthritis in the Beijing population: a prospective cohort study protocol

INTRODUCTION

Millions of patients are currently suffering from pain and dysfunction caused by osteoarthritis (OA), and billions of dollars have been invested into treatment. Because there is no effective treatment that can reverse the progression of knee OA, it is important to determine the risk factors that may influence the progression. However, although there are many studies that examine risk factors for progression, there are only a few that specifically focus on the impact of each risk factor for predicting progression of knee OA. This study aimed to develop a cohort of patients with primary knee OA in the Beijing area to establish models that identify the influence of each risk factor on the prediction of knee OA progression.

METHODS AND ANALYSIS

This is a prospective, multicentre, hospital-based cohort study. The study population comprises 2000 patients with primary knee OA from the Beijing area. The recruitment and baseline visits started in December 2017 and will finish in November 2018. After baseline visits, the patients will be followed for 3 years or until the occurrence of primary outcomes. Demographic variables will be collected during the baseline visit. Influencing factors including occupational exposures, family history and treatment will be collected at baseline and each follow-up visit. The primary outcome measure is a comprehensive index which will be combined with clinical WOMAC score, imaging K-L grade and clinical outcomes. These data will also be collected at baseline and each follow-up visit.

ETHICS AND DISSEMINATION

This study protocol has been approved by Peking University Third Hospital Medical Science Research Ethics Committee. All the eligible participants will give written informed consent. The findings will be published in peer-reviewed journals and presented at national or international conferences. Besides, the results will be disseminated to all participants via the social software 'WeChat'.

TRIAL REGISTRATION NUMBER

ChiCTR-ROC-17013790; preresults.

Systematic review and meta-analysis of the reliability and discriminative validity of cartilage compositional MRI in knee osteoarthritis

OBJECTIVE

To assess reliability and discriminative validity of cartilage compositional magnetic resonance imaging (MRI) in knee osteoarthritis (OA).

DESIGN

The study was carried out per PRISMA recommendations. We searched MEDLINE and EMBASE (1974 - present) for eligible studies. We performed qualitative synthesis of reliability data. Where data from at least two discrimination studies were available, we estimated pooled standardized mean difference (SMD) between subjects with and without OA. Discrimination analyses compared controls and subjects with mild OA (Kellgren-Lawrence (KL) grade 1-2), severe OA (KL grade 3-4) and OA not otherwise specified (NOS) where not possible to stratify. We assessed quality of the evidence using Quality Appraisal of Diagnostic Reliability (QAREL) and Quality Assessment of Diagnostic Accuracy (QUADAS-2) tools.

RESULTS

Fifty-eight studies were included in the reliability analysis and 26 studies were included in the discrimination analysis, with data from a total of 2,007 knees. Intra-observer, inter-observer and test-retest reliability of compositional techniques were excellent with most intraclass correlation coefficients >0.8 and coefficients of variation <10%. T1rho and T2 relaxometry were significant discriminators between subjects with mild OA and controls, and between subjects with OA (NOS) and controls (P < 0.001). T1rho showed best discrimination for mild OA (SMD [95% CI] = 0.73 [0.40 to 1.06], P < 0.001) and OA (NOS) (0.60 [0.41 to 0.80], P < 0.001). Quality of evidence was moderate for both parts of the review.

CONCLUSIONS

Cartilage compositional MRI techniques are reliable and, in the case of T1rho and T2 relaxometry, can discriminate between subjects with OA and controls.

Quantitative analysis of T2 relaxation times of the patellofemoral joint cartilage 3 years after anterior cruciate ligament reconstruction

Objective

To evaluate patient-specific patellofemoral joint (PFJ) cartilage 3 years postoperatively using T2 mapping magnetic resonance imaging and the uninjured contralateral side as control.

Hypothesis

The cartilage of the PFJ in the anterior cruciate ligament (ACL) reconstructed knees would show increased T2 values compared to the uninjured contralateral knees at 3-year follow-up, and the femoral (trochlear) cartilage would be more susceptible than the patella in degeneration in ACL-reconstructed knees.

Methods

Ten patients with clinically successful ACL-reconstructed knees were prospectively enrolled 3 years postoperatively. Sagittal images of both knees were obtained using T2 mapping. Cartilage over the medial, central, and lateral regions of the trochlea and patella was divided into superficial and deep regions. Average T2 values of the cartilage at each region of interest of the ACL-reconstructed and uninjured contralateral knees were compared for each individual patient.

Results

Overall, the T2 values at the superficial layers of the medial and central trochlear cartilage of the ACL-reconstructed knees were significantly higher than those of the uninjured contralateral knees by 4.23 ± 9.09 milliseconds (8.9%; p = 0.043) and 5.94 ± 8.12 milliseconds (10.9%; p = 0.019), respectively. No significant difference was found in other cartilage areas of the trochlea and patella. In individual patient analysis, increased T2 values of ACL-reconstructed knees were found in all 10 patients in at least one superficial region and eight patients in at least one deep region of the trochlear cartilage, five patients in at least one superficial region, and eight patients in at least one deep region of the patellar cartilage.

Conclusion

Despite a clinically satisfactory ACL reconstruction (with negative anteroposterior drawer and pivot shift tests), all patients showed at least one region with increased T2 value of the PFJ cartilage 3 years after ACL reconstruction, especially at the medial compartment of the trochlear cartilage.

The Translational Potential of this Article

Little data has been reported on PFJ cartilage condition after ACL reconstruction. This study could help develop noninvasive diagnostic methods for detection of early PFJ cartilage degeneration after ACL reconstruction.

Morphologic and quantitative magnetic resonance imaging of knee articular cartilage for the assessment of post-traumatic osteoarthritis

Orthopedic trauma, such as anterior cruciate ligament (ACL) disruption, is a common source of osteoarthritis in the knee. Magnetic resonance imaging (MRI) is a non-invasive multi-planar imaging modality commonly used to evaluate hard and soft tissues of diarthrodial joints following traumatic injury. The contrast provided by generated images enables the evaluation of bone marrow lesions as well as delamination and degeneration of articular cartilage. We will provide background information about MRI signal generation and decay (T₁ and T₂ values), the utility of morphologic MRI, and the quantitative MRI techniques of T_1ρ , T₂ , and T₂ * mapping, to evaluate subjects with traumatic knee injuries, such as ACL rupture. Additionally, we will provide information regarding the dGEMRIC, sodium, and gagCEST imaging techniques. Finally, the description and utility of newer post hoc analysis techniques, such as texture analysis, will be given. Continued development and refinement of these advanced MRI techniques will facilitate their clinical translation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:412-423, 2017.

MRI T1ρ and T2 mapping for the assessment of articular cartilage changes in patients with medial knee osteoarthritis after hemicallotasis osteotomy

Objectives

The purpose of this study was to clarify the appearance of the reparative tissue on the articular surface and to analyse the properties of the reparative tissue after hemicallotasis osteotomy (HCO) using MRI T1ρ and T2 mapping.

Methods

Coronal T1ρ and T2 mapping and three-dimensional gradient-echo images were obtained from 20 subjects with medial knee osteoarthritis. We set the regions of interest (ROIs) on the full-thickness cartilage of the medial femoral condyle (MFC) and medial tibial plateau (MTP) of the knee and measured the cartilage thickness (mm) and T1ρ and T2 relaxation times (ms). Statistical analysis of time-dependent changes in the cartilage thickness and the T1ρ and T2 relaxation times was performed using one-way analysis of variance, and Scheffe’s test was employed for post hoc multiple comparison.

Results

The cartilage-like repair tissue appeared on the cartilage surface of the medial compartment post-operatively, and the cartilage thickness showed a significant increase between the pre-operative and one-year post-operative time points (MFC; p = 0.003, MTP; p < 0.001). The T1ρ values of the cartilage-like repair tissue showed no difference over time, however, the T2 values showed a significant decrease between the pre-operative and one-year post-operative time points (MFC; p = 0.004, MTP; p = 0.040).

Conclusion

This study clarified that the fibrocartilage-like repair tissue appeared on the articular surface of the medial compartment after HCO as evidenced by MRI T1ρ and T2 mapping.

Cite this article: H. Nishioka, E. Nakamura, J. Hirose, N. Okamoto, S. Yamabe, H. Mizuta. MRI T1ρ and T2 mapping for the assessment of articular cartilage changes in patients with medial knee osteoarthritis after hemicallotasis osteotomy. Bone Joint Res 2016;5:294–300. DOI: 10.1302/2046-3758.57.BJR-2016-0057.R1.

T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging

T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging's basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs.