301 research outputs found

    The Founder’s Lecture 2009: advances in imaging of osteoporosis and osteoarthritis

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    The objective of this review article is to provide an update on new developments in imaging of osteoporosis and osteoarthritis over the past three decades. A literature review is presented that summarizes the highlights in the development of bone mineral density measurements, bone structure imaging, and vertebral fracture assessment in osteoporosis as well as MR-based semiquantitative assessment of osteoarthritis and quantitative cartilage matrix imaging. This review focuses on techniques that have impacted patient management and therapeutic decision making or that potentially will affect patient care in the near future. Results of pertinent studies are presented and used for illustration. In summary, novel developments have significantly impacted imaging of osteoporosis and osteoarthritis over the past three decades

    Imaging of Osteoarthritis

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    Osteoarthritis (OA) is the most prevalent joint disorder in the elderly, and there is no effective treatment. Imaging is essential for evaluating the synovial joint structures (including cartilage, meniscus, subchondral bone marrow and synovium) for diagnosis, prognosis, and follow-up. This article describes the roles and limitations of both conventional radiography and magnetic resonance (MR) imaging, and considers the use of other modalities (eg, ultrasonography, nuclear medicine, computed tomography [CT], and CT/MR arthrography) in clinical practice and OA research. The emphasis throughout is on OA of the knee. This article emphasizes research developments and literature evidence published since 2008

    The role of bone marrow lesions in knee osteoarthritis:textural analysis of subchondral bone

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    Abstract. Osteoarthritis (OA) is the most common joint disorder in the world that affects various joints particularly hand, hip, and knee joint. The knee OA has been identified as the most impactful OA because it is the major cause of disability worldwide. Generally, OA progression leads to joint replacement surgery and causes enormous amount of financial costs. Thus, it is crucial to diagnose OA at an early stage and prevent or slow down its progression. Currently, clinical diagnosis of OA includes physical examination and clinical imaging. However, they are insensitive to early OA changes. On the other hand, it was shown that several imaging bio markers can be captured at an early stage of the disease. One of the important imaging bio markers for OA is the alternations of subchondral bone texture. Besides, there are other factors that cause these alternations such as bone marrow lesions (BML). Two sub-studies have been conducted in this thesis. The aim of the first sub-study is to investigate the association between BML and OA diagnosis by using subchondral bone texture from plain radiography. OA subjects are defined by Kellgren-Lawrence (KL) grading scale. KL grade 0 and 1 represent no OA and grade 2, 3, and 4 are OA subjects. In this work, subjects at the baseline (first visit) of osteoarthritis initiative (OAI) dataset were selected. Then, they were categorised into three groups including subjects who has BML in medial tibia (group 1), subjects without BMLs at all (group 2), and lastly the subjects without medial tibia BMLs (group 3). In the next step, region of interest (ROI) was selected at the margin of medial tibia in plain radiographs. After that, 29 textural features from 4 textural descriptors including grey-level co-occurrence matrix (GLCM), histogram of image, absolute gradient, and fractal signature analysis (FSA) were computed from the extracted ROI. Subsequently, Fisher’s exact test and Mann–Whitney U test were used in order to discover how textural features change among OA and non OA subjects in each group (first analysis) and how those differences change across the groups (second analysis). Our results showed that there are significant textural differences between OA and non OA subjects when they have BMLs at medial tibia. Moreover, there were no significant textural differences among subjects with no BMLs and subjects with no BMLs in medial tibia. These results indicate that the presence of BML as well as its location at subchondral bone may have association with OA incidence. In the second sub-study, for research oriented purposes we built a deep convolutional neural network (CNN) based models to automatically detect OA from subchondral bone texture according to the Kellgren-Lawrence (KL) grading scale. We selected subjects without BMLs to make a fair comparison between magnetic resonance imaging (MRI) data and plain radiographs. In this study, subjects with no BMLs who have sagittal 3-D Double Echo Steady State sequence (3D DESS MRI) and plain radiography at the baseline of OAI were selected. In both imaging modalities, square sized ROIs were chosen located at the marginal region of medial tibia. Confusion matrix and area under the receiver operating characteristics curve (ROC AUC) were used to evaluate the model performance. Our results demonstrated that when subjects do not have BMLs, our model was not able to detect OA from the subchondral bone texture

    T1ρ and T2 relaxation times predict progression of knee osteoarthritis

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    SummaryObjectiveTo evaluate whether T2 and T1ρ relaxation times of knee cartilage determined with 3T magnetic resonance imaging (MRI) at baseline predict longitudinal progression of cartilage degenerative changes.MethodsQuantitative analysis of cartilage was performed using 3T MRI with both T2 and T1ρ mapping techniques in 55 subjects without evidence of severe osteoarthritis (OA) [Kellgren–Lawrence (KL) score of 0–3] at baseline. Morphological abnormalities of cartilage, menisci, ligaments and bone marrow were analyzed on sagittal fat-saturated intermediate-weighted fast spin echo (FSE) sequences. Progression of degenerative changes was analyzed over a period of 2 years. Progression was detected in 27 subjects while in 28 subjects no changes were found. Differences between T2 and T1ρ relaxation times in these two cohorts were compared using one-way analysis of variance (ANOVA) and t tests.ResultsBaseline T2 and T1ρ values were significantly higher in the progression cohort in all compartments (P < 0.05) except the lateral tibia (LT) for T2 and the medial tibia (MT) for T1ρ. Progression of cartilage degenerative disease was most pronounced at the medial femoral condyles and at the femoro-patellar joint; differences between the two cohorts for T2 and T1ρ were also most significant in these compartments.ConclusionsT2 and T1ρ measurements were significantly higher at baseline in individuals that showed progression of cartilage abnormalities over a period of 2 years and may therefore serve as potential predictors for progression of degenerative cartilage abnormalities in knee OA

    Association of blood pressure with knee cartilage composition and structural knee abnormalities: data from the osteoarthritis initiative.

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    ObjectiveTo investigate the associations of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with changes in knee cartilage composition and joint structure over 48&nbsp;months, using magnetic resonance imaging (MRI) data from the Osteoarthritis Initiative (OAI).Materials and methodsA total of 1126 participants with right knee Kellgren-Lawrence (KL) score 0-2 at baseline, no history of rheumatoid arthritis, blood pressure measurements at baseline, and cartilage T2 measurements at baseline and 48&nbsp;months were selected from the OAI. Cartilage composition was assessed using MRI T2 measurements, including laminar and gray-level co-occurrence matrix texture analyses. Structural knee abnormalities were graded using the whole-organ magnetic resonance imaging score (WORMS). We performed linear regression, adjusting for age, sex, body mass index, physical activity, smoking status, alcohol use, KL score, number of anti-hypertensive medications, and number of nonsteroidal anti-inflammatory drugs.ResultsHigher baseline DBP was associated with greater increases in global T2 (coefficient 0.22 (95% CI 0.09, 0.34), P = 0.004), global superficial layer T2 (coefficient 0.39 (95% CI 0.20, 0.58), P = 0.001), global contrast (coefficient 15.67 (95% CI 8.81, 22.53), P &lt; 0.001), global entropy (coefficient 0.02 (95% CI 0.01, 0.03) P = 0.011), and global variance (coefficient 9.14 (95% CI 5.18, 13.09), P &lt; 0.001). Compared with DBP, the associations of SBP with change in cartilage T2 parameters and WORMS subscores showed estimates of smaller magnitude.ConclusionHigher baseline DBP was associated with higher and more heterogenous cartilage T2 values over 48&nbsp;months, indicating increased cartilage matrix degenerative changes

    7th International Workshop on Osteoarthritis Imaging report: “imaging in OA – now is the time to move ahead”

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    SummaryThe 7th Osteoarthritis Research Society International (OARSI) International Workshop on Osteoarthritis Imaging was held in Reykjavik, Iceland, from July 9–12, 2014; attracting attendees from academia, pharmaceutical and Magnetic resonance imaging (MRI) industries, as well as a large number of young investigators. The Workshop program consisted of six modules, including imaging in osteoarthritis (OA), imaging and pain in OA, new techniques in imaging, risk factors and structural outcomes, anti-nerve growth factor (a-NGF) therapy, and joint replacement. A wealth of data was presented from OA researchers from all over the world and participants gained insightful knowledge on up-to-date research work focusing on imaging of OA. This paper presents a summary of the salient points from the workshop.ConclusionsIdentifying the appropriate imaging modality and parameters will be critical for ensuring responsive, reproducible and reliable outcomes for clinical trials. Continued efforts from the OA research community are needed to establish the most effective use of imaging in OA clinical trials, including anti-NGF therapy and joint replacement trials, and to validate newer imaging techniques such as compositional MRI for use in the future clinical trials

    Osteoimmunology and osteoporosis

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    The concept of osteoimmunology is based on growing insight into the links between the immune system and bone at the anatomical, vascular, cellular, and molecular levels. In both rheumatoid arthritis (RA) and ankylosing spondylitis (AS), bone is a target of inflammation. Activated immune cells at sites of inflammation produce a wide spectrum of cytokines in favor of increased bone resorption in RA and AS, resulting in bone erosions, osteitis, and peri-inflammatory and systemic bone loss. Peri-inflammatory bone formation is impaired in RA, resulting in non-healing of erosions, and this allows a local vicious circle of inflammation between synovitis, osteitis, and local bone loss. In contrast, peri-inflammatory bone formation is increased in AS, resulting in healing of erosions, ossifying enthesitis, and potential ankylosis of sacroiliac joints and intervertebral connections, and this changes the biomechanical competence of the spine. These changes in bone remodeling and structure contribute to the increased risk of vertebral fractures (in RA and AS) and non-vertebral fractures (in RA), and this risk is related to severity of disease and is independent of and superimposed on background fracture risk. Identifying patients who have RA and AS and are at high fracture risk and considering fracture prevention are, therefore, advocated in guidelines. Local peri-inflammatory bone loss and osteitis occur early and precede and predict erosive bone destruction in RA and AS and syndesmophytes in AS, which can occur despite clinically detectable inflammation (the so-called 'disconnection'). With the availability of new techniques to evaluate peri-inflammatory bone loss, osteitis, and erosions, peri-inflammatory bone changes are an exciting field for further research in the context of osteoimmunology

    Histological characterization of CT-identified osteoarthritic subchondral cysts and co-registration of CT with MRI

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    Osteoarthritis (OA) is a chronic disease that affects the joints, most commonly hands, hips, knees, feet, and spine (Litwic et al. 2013). The disease becomes more common with advanced age and is one of the most prevalent causes of disability in older populations. Currently there is no cure besides total joint replacement surgery, and there will be approximately 4 million Americans living with a hip replacement by the end of the next decade (Maradit Kremers et al. 2015). Osteoarthritis was classically characterized as a disease of progressive articular cartilage degradation, but the degeneration involves all tissues of the synovial joint including the periarticular muscles, joint capsule, synovium, ligaments, and subchondral and metaphyseal bone. The cause of pain in OA is not well understood, but it is known that bone marrow lesions (BMLs) identified in subchondral bone by MRI are an important determinant of pain (Felson et al. 2001; Kumar et al. 2013). Abnormal blood vessel growth may be responsible MRI signature of BMLs, and the commonality between pathways for angiogenesis and neurogenesis suggests this pathologic process may be the source of pain in OA. The objective of this study was to characterize the histologic nature of subchondral cysts identified by micro computed tomography (μCT) which had been registered with MRI images in which marrow lesions were identified. Femoral heads were collected from 10 patients (6 females and 4 females; age 29-80) who underwent total hip arthroplasty. All patients had MRIs performed within 6 months prior to surgery. The heads were fixed and scanned with μCT to identify cysts in the subchondral bone. A block of the femoral head containing the cyst of interest was resected and processed for histologic analysis. The sections were stained with either Safranin-O and Fast Green or hematoxylin and eosin to view the nature and composition of the tissue. A two-dimensional image from the μCT that corresponded to the histologic slice was matched with a coronal view from the MRI. The primary compressive group was reliably identified on μCT images and served as good indicator for orienting the CT to match with the MRI. The subchondral cysts that were matched to MRI all consisted of predominantly fibrous bone marrow and frequently had a large number of blood vessels within the tissue. Three of the eight cysts had cartilage intrusions that were located mostly within peripheral trabecular bone, though one cyst contained a nodule of cartilage surrounded by organized fibers with the texture of granulation tissue. The process of image registration was mostly performed manually, but the development of this process will contribute to a more refined, semi-automated process in the future. The ability to correlate the histopathology of CT-identified lesions with a signature patter on MRI will be an important tool for better characterizing the nature of BMLs and understanding the pathogenesis of OA
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