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Objective: To investigate which magnetic resonance imaging (MRI)-based articular pathologies are predictive of subsequent medial femorotibial compartment quantitative cartilage thickness loss and therefore suitable for enrichment of clinical trials with participants showing a high likelihood for structural progression., Methods: Semiquantitative MRI Osteoarthritis Knee Score (MOAKS) assessments at baseline and quantitative cartilage thickness measurements at baseline and year-2 follow-up were performed in 599 participants (age 62 years; body mass index 31 kg/m 2 ; 59% female) from the Osteoarthritis Initiative-based Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium. Knees were classified as medial femorotibial compartment (MFTC) progressors or nonprogressors based on MFTC cartilage thickness change (smallest detectable change threshold -111 μm). Logistic regression was used to investigate the association between baseline presence and severity of MFTC MOAKS pathologies with subsequent MFTC progression. The standardized response mean (SRM) was computed to estimate the sensitivity to change that can be achieved when selecting knees based on MOAKS pathologies., Results: Presence of MFTC MOAKS cartilage damage (odds ratio [OR] 2.77 [95% confidence interval (95% CI) 1.76, 4.36]), MFTC bone marrow lesions (OR 2.69 [95% CI 1.89, 3.83]), medial meniscus extrusion or damage (OR 2.21 [95% CI 1.37, 3.55]), as well as MOAKS severity subscales for cartilage and meniscus damage were associated with subsequent progression. The SRM was greater in knees with than in knees without the presence of these pathologies and was associated with the severity of those pathologies., Conclusion: MRI-based grading of articular pathologies makes it possible to specifically select progressor knees suitable for inclusion in clinical trials but also to identify knees in which treatment is not indicated (e.g., knees without cartilage damage despite presence of radiographic osteoarthritis)., (© 2022 The Authors. Arthritis Care & Research published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Objective: To study whether layer-specific cartilage transverse relaxation time (T2) and/or longitudinal change is associated with clinically relevant knee osteoarthritis (OA) disease progression., Methods: The Foundation for the National Institutes of Health Biomarker Consortium was a nested case-control study on 600 knees from 600 Osteoarthritis Initiative participants. Progressor knees had both medial tibiofemoral radiographic joint space width (JSW) loss (≥0.7 mm) and a persistent increase in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score (≥9 on a 0-100 scale) at 24-48 months from baseline (n = 194). Multiecho spin-echo (MESE) magnetic resonance images (MRIs) for cartilage T2 analysis had been acquired in the right knees only (97 progressor knees). These were compared to 104 control knees without JSW or pain progression. Fifty-three knees had JSW progression, and 57 pain progression only. Cartilage thickness segmentations obtained from double-echo steady-state MRI were matched to MESE MRI to extract superficial and deep femorotibial cartilage T2. Superficial medial femorotibial compartment (MFTC) T2 at baseline was the primary, and change in deep MFTC T2 between baseline and 12 months was the secondary analytic outcome of this post hoc exploratory study., Results: Baseline superficial MFTC T2 was significantly elevated in progressor knees (adjusted mean 47.2 msec [95% confidence interval (95% CI) 46.5, 48.0]) and JSW progression only knees (adjusted mean 47.3 msec [95% CI 46.3, 48.3]), respectively, versus non-progressor knees (45.8 msec [95% CI 45.0, 46.5]) after adjustment for age, sex, body mass index, WOMAC pain score, and medial joint space narrowing grade (analysis of covariance). Change in T2 was not significantly associated with case status., Conclusion: Baseline superficial, but not deep, medial cartilage T2 is associated with clinically relevant disease progression in knee OA., (© 2021 The Authors. Arthritis Care & Research published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Objective: To study the longitudinal performance of fully automated cartilage segmentation in knees with radiographic osteoarthritis (OA), we evaluated the sensitivity to change in progressor knees from the Foundation for the National Institutes of Health OA Biomarkers Consortium between the automated and previously reported manual expert segmentation, and we determined whether differences in progression rates between predefined cohorts can be detected by the fully automated approach., Methods: The OA Initiative Biomarker Consortium was a nested case-control study. Progressor knees had both medial tibiofemoral radiographic joint space width loss (≥0.7 mm) and a persistent increase in Western Ontario and McMaster Universities Osteoarthritis Index pain scores (≥9 on a 0-100 scale) after 2 years from baseline (n = 194), whereas non-progressor knees did not have either of both (n = 200). Deep-learning automated algorithms trained on radiographic OA knees or knees of a healthy reference cohort (HRC) were used to automatically segment medial femorotibial compartment (MFTC) and lateral femorotibial cartilage on baseline and 2-year follow-up magnetic resonance imaging. Findings were compared with previously published manual expert segmentation., Results: The mean ± SD MFTC cartilage loss in the progressor cohort was -181 ± 245 μm by manual segmentation (standardized response mean [SRM] -0.74), -144 ± 200 μm by the radiographic OA-based model (SRM -0.72), and -69 ± 231 μm by HRC-based model segmentation (SRM -0.30). Cohen's d for rates of progression between progressor versus the non-progressor cohort was -0.84 (P < 0.001) for manual, -0.68 (P < 0.001) for the automated radiographic OA model, and -0.14 (P = 0.18) for automated HRC model segmentation., Conclusion: A fully automated deep-learning segmentation approach not only displays similar sensitivity to change of longitudinal cartilage thickness loss in knee OA as did manual expert segmentation but also effectively differentiates longitudinal rates of loss of cartilage thickness between cohorts with different progression profiles., (© 2020 The Authors. Arthritis Care & Research published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Objective: To investigate the association of cartilage thickness change over 24 months, as determined by magnetic resonance imaging (MRI), with knee osteoarthritis (OA) progression at 24-48 months., Methods: This nested case-control study included 600 knees with a baseline Kellgren/Lawrence (K/L) grade of 1-3 from 600 Osteoarthritis Initiative (OAI) participants. Case knees (n = 194) had both medial tibiofemoral radiographic joint space loss (≥0.7 mm) and a persistent increase in the Western Ontario and McMaster Universities Osteoarthritis Index pain score (≥9 on a 0-100 scale) 24-48 months from baseline. Control knees (n = 406) included 200 with neither radiographic nor pain progression, 103 with radiographic progression only, and 103 with pain progression only. Medial and lateral femorotibial cartilage was segmented from sagittal 3T MRIs at baseline, 12 months, and 24 months. Logistic regression was used to assess the association of change in cartilage thickness, with a focus on the central medial femorotibial compartment, and OA progression., Results: Central medial femorotibial compartment thickness loss was significantly associated with case status, with an odds ratio (OR) of 1.9 (95% confidence interval [95% CI] 1.6-2.3) (P < 0.0001). Association with case status reached P < 0.05 for both the central femur (OR 1.8 [95% CI 1.5-2.2]) and the central tibia (OR 1.6 [95% CI 1.3-1.9]). Lateral femorotibial compartment cartilage thickness loss, in contrast, was not significantly associated with case status. A reduction in central medial femorotibial compartment cartilage thickness was strongly associated with radiographic progression (OR 4.0 [95% CI 2.9-5.3]; P < 0.0001) and only weakly associated with pain progression (OR 1.3 [95% CI 1.1-1.6]; P < 0.01)., Conclusion: Our findings indicate that loss of medial femorotibial cartilage thickness over 24 months is associated with the combination of radiographic and pain progression in the knee, with a stronger association for radiographic progression., (© 2015, American College of Rheumatology.)

Background: A high degree of meniscal body extrusion on knee magnetic resonance imaging has been shown to be strongly associated with development of knee osteoarthritis. However, very little is known about meniscal position in the asymptomatic knee and its natural history. Hence our objective was to study meniscal body position and its change over 4 years in asymptomatic adults., Methods: Cohort study using data from the Osteoarthritis Initiative (OAI) involving four clinical sites in the United States (Baltimore, Maryland, Pawtucket, Rhode Island, Columbus, Ohio, and Pittsburgh, Pennsylvania). We studied both knees from 118 subjects (mean age 55 years, 61% women, mean body mass index 24.4) from the OAI "non-exposed" reference cohort free of knee pain, radiographic knee osteoarthritis and risk factors for knee osteoarthritis at baseline. We assessed mid-coronal intermediate-weighted 3-Tesla magnetic resonance images from baseline and the 2- and 4-year follow-up visit. One observer measured tibia plateau, meniscal body width and meniscal body extrusion in both compartments. We calculated meniscal overlap distance on the tibial plateau, % coverage, and extrusion index compared to tibia width. Potential trends in position over the 4-year period were evaluated using a linear mixed-effects regression model., Results: The mean (SD) values at baseline for medial meniscal body extrusion and overlap distance were 1.64 mm (0.92) and 10.1 mm (3.5), and coverage was 34.4% (11.9). The corresponding values for the lateral compartment were 0.63 mm (0.73), 9.8 mm (2.4), and 31.0% (7.7). Medial meniscus body extrusion index was greater in female knees (p = 0.03). There was slight increase in medial meniscal body extrusion over 4 years (0.040 mm/year [95% CI: 0.019-0.062]). The other variables were relatively stable., Conclusions: In asymptomatic adults, the relative degree of meniscus body extrusion is more pronounced in female knees. Although a slight increase in extrusion over time was noted for the medial body, positions were relatively stable within subjects over time.

The morphological and biological characteristics of the 5 subspecies of Culicoides variipennis as proposed by Wirth and Jones are reviewed in the light of research performed since 1957. Proposals have been made to recognize the eastern and western populations as distinct species; others prefer to consider the population as 1 species with extensive and complex variation resulting from the interplay of ecological and genetic factors. The authors recommend the use of the term "variipennis complex" rather than a haphazard selection of 1 of the 5 names in reporting the results of research on this insect, until such time as the necessary biosystematic studies have been made to determine the genetic nature of the population structure over the entire geographic range of the species. If it is considered desirable to recognize the western form as a distinct entity, reasons are given for preference to the name sonorensis rather than occidentalis. The use of gas chromatography to study population differences in the makeup of cuticular paraffins is suggested as a promising new biochemical approach to the study of the genetic and physiological differences between populations of variipennis.