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Level of evidence5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019.

BackgroundMapping of T1ρ relaxation time is a quantitative magnetic resonance (MR) method and is frequently used for analyzing microstructural and compositional changes in cartilage tissues. However, there is still a lack of study investigating the link between T1ρ relaxation time and a feasible constitutive relation of cartilage which can be used to model complicated mechanical behaviors of cartilage accurately and properly.MethodsThree-dimensional finite element (FE) models of ten in vitro human tibial cartilage samples were reconstructed such that each element was assigned by material-level parameters, which were determined by a corresponding T1ρ value from MR maps. A T1ρ-based fibril-reinforced poroviscoelastic (FRPE) constitutive relation for human cartilage was developed through an inverse FE optimization technique between the experimental and simulated indentations.ResultsA two-parameter exponential relationship was obtained between the T1ρ and the volume fraction of the hydrated solid matrix in the T1ρ-based FRPE constitutive relation. Compared with the common FRPE constitutive relation (i.e., without T1ρ), the T1ρ-based FRPE constitutive relation indicated similar indentation depth results but revealed some different local changes of the stress distribution in cartilages.ConclusionsOur results suggested that the T1ρ-based FRPE constitutive relation may improve the detection of changes in the heterogeneous, anisotropic, and nonlinear mechanical properties of human cartilage tissues associated with joint pathologies such as osteoarthritis (OA). Incorporating T1ρ relaxation time will provide a more precise assessment of human cartilage based on the individual in vivo MR quantification.

PurposeTo investigate the changes in landing biomechanics over a 3-year period and their correlation with cartilage degenerative changes in the medial tibiofemoral joint of the knee after anterior cruciate ligament reconstruction (ACLR) using magnetic resonance T1ρ mapping.MethodsThirty-one anterior cruciate ligament-injured patients underwent magnetic resonance imaging of the injured knee before ACLR and 3 years after ACLR, as well as biomechanical analysis of a drop-landing task at 6 months and 3 years after ACLR. Sixteen healthy individuals were recruited and underwent knee magnetic resonance imaging and biomechanical assessment during a drop-landing task. T1ρ cartilage relaxation times were calculated for the medial femur and tibia.ResultsACLR patients exhibited increased peak vertical ground reaction force (VGRF), VGRF impulse, peak knee flexion moment (KFM), and KFM impulse from 6 months to 3 years (P < .001 for each). Although the ACLR knees showed significantly lower peak VGRF and KFM at 6 months (P < .001 for both) when compared with the controls, there were no significant differences at 3 years. At 3 years, ACLR patients showed higher T1ρ values over the medial femur (P < .001) and tibia (P = .012) when compared with their preoperative values and with healthy control values. Within the ACLR group, side-to-side differences in peak VGRF and sagittal knee biomechanics at 6 months were associated with increased T1ρ values from baseline to 3 years.ConclusionsThe results of this longitudinal study show that landing biomechanics are altered after ACLR but biomechanical abnormalities tend to recover at 3 years after ACLR. Differences in lower-extremity mechanics during a landing task at 6 months may be associated with cartilage degeneration at 3 years after anterior cruciate ligament injury and reconstruction.Level of evidenceLevel II, prospective trial.

BackgroundAn altered tibial position is still present despite anterior cruciate ligament (ACL) reconstruction. It has been demonstrated that an abnormal tibial position after an ACL injury may play a role in subsequent injuries to the meniscus, which can lead to early cartilage degeneration.PurposeTo determine changes in both the tibial position and the meniscal matrix present before and after ACL reconstruction as well as to evaluate the association between these 2 variables in ACL-injured knees 3 years after reconstruction.Study designCohort study; Level of evidence, 2.MethodsBilateral knee magnetic resonance imaging (MRI) of 32 patients with unilateral ACL injuries was performed before reconstruction; 13 control participants also underwent MRI. Follow-up MRI was performed up to 3 years after surgery. Tibial position, internal tibial rotation, and T1ρ and T2 values of the menisci were calculated using an in-house MATLAB program. Student t tests and multiple linear regression were used to compare differences between injured, uninjured, and control knees as well as to assess correlations between the tibial position at 3 years and 3-year changes in quantitative MRI meniscal relaxation values.ResultsThe tibial position of injured knees was more anterior than that of uninjured knees at baseline, 6 months, and 1, 2, and 3 years (P < .05 for all). The T1ρ and T2 values of the menisci of injured knees were greater than those of uninjured and control knees in the posterior lateral and posterior medial horns up to 1 and 2 years after surgery, respectively (P < .05 for all). The tibial position at 3 years was associated with increased T2 values from baseline to 3 years in the posterior medial horn (β = 0.397; P = .031) and anterior medial horn (β = 0.360; P = .040).ConclusionResults of the current study indicate that there is a persistently altered tibial position after ACL reconstruction. Initial preoperative meniscal abnormalities show prolonged but gradual improvement. Additionally, correlations between the tibial position and changes in the medial meniscal matrix suggest that the tibial position may play a role in the increased susceptibility to medial meniscal tears seen after reconstruction. The development of newer surgical techniques must address a persistently altered tibial position. Quantitative MRI is an effective instrument to evaluate meniscal matrix changes and can serve as an early radiological tool for meniscal injuries.

This article reported a 38-year-old female patient who was misdiagnosed as Sjögren’s syndrome complicated with type I distal renal tubular acidosis （dRTA） due to recurrent hypokalemia, alkaline urine, elevated urinary potassium, positive antinuclear body（ANA）, and positive anti-SSA antibody. The diagnosis of Sjögren’s syndrome was then excluded because the patient had no obvious dry mouth or dry eyes, and the results of unstimulating saliva flow rate, corneal fluorescence staining, Schirmer secretion test, or labial gland biopsy were all negative. The clinical manifestations, such as metabolic alkalosis, hypochloremia, hypomagnesemia and low urinary calcium,could not support the diagnosis of dRTA. The patient presented with severe hypomagnesemia and a Trousseau sign, then Gitelman syndrome was finally confirmed based on genetic testing. Therefore, the diagnosis and treatment of this case prompted that for patients with recurrent hypokalemia and positive anti-SSA antibody, clinicians should make differential diagnosis based on the acid-base imbalance and the electrolyte disturbance at first, instead of paying too much attention to autoantibodies and Sjögren’s syndrome, to avoid being misled by the ANA and anti-SSA antibody.

Bone marrow adiposity is associated with aging, osteoporosis, and reduced hematopoiesis, as well as anorexia nervosa, but little is known about the underlying mechanisms that affect marrow adiposity. Chronic kidney disease (CKD) may influence bone marrow adipose tissue (BMAT), possibly through loss of lean mass or higher circulating levels of sclerostin. To test these hypotheses, we investigated the cross-sectional association between estimated glomerular filtration rate (eGFR) as a measure of kidney function and 1 H-MRS-based measurement of vertebral BMAT (L1 to L4) in 475 older adults from the Age Gene/Environment Susceptibility (AGES)-Reykjavik study. Mean BMAT was compared in those with eGFR >60 (n = 297) versus those with eGFR 45 to 60 (n = 120) or eGFR 60 (adjusted mean 53.8%; 95% CI, 52.8 to 54.8) (p = 0.0002). BMAT did not differ in those with eGFR 45 to 60 (adjusted mean 54.3%; 95% CI, 52.8 to 55.9) compared with those with eGFR >60 (p = 0.58). In a subgroup of participants with serum sclerostin available (n = 253), additional adjustment for sclerostin attenuated the difference in adjusted mean vertebral BMAT between those with eGFR 60 from 3.7% (p = 0.04) to 2.4% (p = 0.20). CKD stage 3b or worse was associated with greater bone marrow adiposity; this association may be partially mediated by sclerostin. © 2018 American Society for Bone and Mineral Research.

A highly selective fluorescent "turn on" probe for Al3+ based on the conjugate of aminourea and pyrazolone was devised and synthesized. The fluorescence intensity of the probe solution was significantly enhanced by the addition of Al3+ to the probe solution. Other cations such as Cu2+, Ni2+, Fe3+, Co2+, Ag+, Mn2+, Sn2+, Sn4+, Mg2+, Li+, Zn2+, Zr4+, Ce3+, Ca2+, and Na+ did not interfere the detection of Al3+. The 1 : 1 complexation between Al3+ and the probe was confirmed by Job's plot curve. In addition, the solution of the complex formed by Al3+ and the probe can be used for the specific detection of Hg2+, appearing as fluorescence quenching. [ABSTRACT FROM AUTHOR]

The fusion of low-resolution hyperspectral images (LR-HSI) with high-resolution multispectral images (HR-MSI) provides a cost-effective approach to obtaining high-resolution hyperspectral images (HR-HSI). Existing methods primarily based on convolutional neural networks (CNNs) struggle to capture global features and do not adequately address the significant scale and spectral resolution differences between LR-HSI and HR-MSI. To tackle these challenges, our novel FCSwinU network leverages the spectral fast Fourier convolution (SFFC) module for spectral feature extraction and utilizes the Swin Transformer's self-attention mechanism for multi-scale global feature fusion. FCSwinU employs a UNet-like encoder–decoder framework to effectively merge spatiospectral features. The encoder integrates the Swin Transformer feature abstraction module (SwinTFAM) to encode pixel correlations and perform multi-scale transformations, facilitating the adaptive fusion of hyperspectral and multispectral data. The decoder then employs the Swin Transformer feature reconstruction module (SwinTFRM) to reconstruct the fused features, restoring the original image dimensions and ensuring the precise recovery of spatial and spectral details. Experimental results from three benchmark datasets and a real-world dataset robustly validate the superior performance of our method in both visual representation and quantitative assessment compared to existing fusion methods. [ABSTRACT FROM AUTHOR]

Background: Ureaplasma spp. can be classified into different serovars. It is unknown whether distinct serovars are associated with clinical signs and symptoms. Methods: We conducted a multicentre cross-sectional study. U. parvum serovars were identified on the basis of their multiple-banded antigen (MBA) genes. After adjusting for demographic variables and other reproductive tract infections, the odds ratio (OR) and 95% confidence interval (CI) were calculated to determine the impact of U. parvum serovars on clinical symptoms. Results: Among 5,277 individuals, U. parvum serovars 3 and 6 were the most prevalent serovars (17.9% and 16.0%, respectively). Potential confounders, such as age, body mass index (BMI), ethnicity, education level, contraceptive methods, number of sexual partners, gravidity, parity, and other sexually transmitted infections (STIs) that are associated with clinical symptoms (P < 0.1) were adjusted for in the univariate analysis. U. parvum serovar 14 was strongly positively associated with certain clinical symptoms, including redness and swelling of the vaginal wall (crude OR: 3.53, 95% CI: 1.92–6.49; adjusted OR: 5.21, 95% CI: 2.56–10.58), cervical bleeding and swelling (crude OR: 3.89, 95% CI: 2.38–6.36; adjusted OR: 7.37, 95% CI: 3.82–14.23), and cervical ectropion (crude OR: 2.08, 95% CI: 1.25–3.45; adjusted OR: 3.04, 95% CI: 1.60–5.74). In contrast, U. parvum serovar 3 was negatively associated with a variety of clinical symptoms, whereas no correlations were detected between U. parvum serovars 1and 6 with clinical symptoms. Conclusions: Different U. parvum serovars exhibit distinct correlations with clinical symptoms, suggesting that U. parvum serovars are pathogenically heterogeneous and that further differentiation of serovars may be necessary. Trial registration: The study was registered with ClinicalTrials.gov (https://www.clinicaltrials.gov; ID: NCT04694495; Registration Date: 2021–01-05). [ABSTRACT FROM AUTHOR]

Generating real‐world evidence about the effect of medication discontinuation or dose reduction on outcomes, such as reduction of adverse drug effects (ADE; intended benefit) and occurrence of adverse drug withdrawal events (ADWE; unintended harm), is crucial to informing deprescribing decisions. Determining the causal effects of deprescribing is difficult for many reasons, including lack of randomization in real‐world study designs and other design and measurement issues that pose threats to internal validity. The inherent challenge is how to identify the effects, both intended benefits and unintended harms, of a new medication stoppage or reduction when implemented in patients with many potential clinical and social risks that may influence the likelihood of deprescribing as well as outcomes. We discuss methodological issues of estimating the effect of medication discontinuation or reduction on risk of ADEs and ADWEs considering: (1) sampling study populations of sufficient size with the potential to demonstrate clinically meaningful and quantifiable outcomes, (2) accurate and appropriately timed measurement of covariates, outcomes, and discontinuation, and (3) statistical approaches to managing confounding and other biases inherent in long‐term medication use by individuals with multiple morbidities. Designing rigorous deprescribing studies that address internal validity threats will support evidence generation by improving the ability to assess benefits and harms when the exposure of interest is the absence of a medication. Iterative learnings about data quality, variable definition, variable measurement, and exposure‐outcome associations will inform strategies to improve the causal inferences possible in real‐world deprescribing studies. [ABSTRACT FROM AUTHOR]

Patients who have suffered ACL injury are more likely to develop early onset post-traumatic osteoarthritis despite reconstruction. The purpose of our study was to evaluate the longitudinal changes in the tibiofemoral cartilage contact area size and location after ACL injury and reconstruction. Thirty-one patients with isolated unilateral ACL injury were followed with T2 weighted Fast Spin Echo, T1ρ and T2 MRI at baseline prior to reconstruction, and 6 months, 1 year, and 2 years after surgery. Areas were delineated in FSE images with an in-house Matlab program using a spline-based semi-automated segmentation algorithm. Tibiofemoral contact area and centroid position along the anterior-posterior axis were calculated along with T1ρ and T2 relaxation times on both the injured and non-injured knees. At baseline, the injured knees had significantly smaller and more posteriorly positioned contact areas on the medial tibial surface compared to corresponding healthy knees. These differences persisted 6 months after reconstruction. Moreover, subjects with more anterior medial centroid positions at 6 months had elevated T1ρ and T2 measures in the posterior medial tibial plateau at 1 year. Changes in contact area and centroid position after ACL injury and reconstruction may characterize some of the mechanical factors contributing to post-traumatic osteoarthritis. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2718-2727, 2018.

ObjectivesTo assess (i) normal imaging anatomy of the popliteomeniscal fascicles, (ii) prevalence and natural evolution of popliteomeniscal fascicle tears (PMFT) in subjects with traumatic anterior cruciate ligament (ACL) tears over 2 years and (iii) compare knee cartilage degeneration in subjects with and without PMFT longitudinally.Methods57 subjects with ACL tears were screened for PMFT. Morphological (high-resolution 3D fast spin-echo) and compositional (T1ρ and T2 mapping) MR imaging was performed prior to and 2 years after ACL reconstruction. Differences of morphological and compositional parameters were compared between subjects with and without PMFT using logistic regression, adjusting for age, sex and BMI.ResultsIn 24% (n = 14) of the subjects with ACL tear a PMFT was detected on baseline MRI. One subject with PMFT developed a meniscal tear over 2 years. Cartilage ∆T1ρ of the lateral femur increased significantly more in subjects with isolated PMFT compared to controls (mean difference, 2.0 ± 2.9 vs. -1.3 ± 1.6, p = 0.027).ConclusionPMFT detected by MRI are a common finding in subjects with ACL tears. Subjects with these defects showed higher compositional cartilage deterioration compared to controls, over 2 years in the lateral femoral compartment, indicating accelerated cartilage degeneration.Key points• Popliteomeniscal fascicle lesions are a common finding in subjects with ACL tears. • Progression to a meniscal tear over 2 years is not frequent. • Anteroinferior popliteomeniscal fascicle is injured most frequently. • Patients with popliteomeniscal fascicle lesions showed accelerated cartilage degeneration.

ContextHigher bone marrow fat (BMF)1 is associated with osteoporosis and reduced hematopoiesis. Exogenous estradiol reduces BMF in older women, but effects of endogenous sex hormones are unknown.ObjectiveTo determine if endogenous sex hormones are associated with BMF in older men and women.Design, setting and participantsCross-sectional study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Participants using medications that may affect BMF were excluded.Main outcome measuresVertebral BMF was measured with magnetic resonance spectroscopy. Estradiol, testosterone and sex hormone binding globulin were measured on archived serum. Linear regression models were adjusted for age, total percent body fat and visit window.ResultsAnalyses included 244 men and 226 women, mean age 81.5 (SD 4.1) years. Mean BMF was 54.1% (SD 8.6) (men) and 54.7% (SD 8.1) (women). In adjusted models, per 1pg/ml increase in total estradiol, there was a statistically significant 0.26% decrease in BMF in men (95% CI: -0.41, -0.11) and a non-significant 0.20% decrease in women (95% CI: -0.55, 0.15), with no evidence of interaction by gender (p=0.88). Per 10ng/dl increase in total testosterone, there was a significant 0.10% decrease in BMF in men (95% CI: -0.17, -0.03) and a non-significant 0.13% (95% CI: -0.79, 0.53) decrease in women, with no evidence of interaction by gender (p=0.97).ConclusionHigher bone marrow fat is associated with lower total estradiol and testosterone levels in older men, with a similar but statistically non-significant association in older women. Sex hormone levels appear to play a role in the regulation of bone marrow fat in older adults.