Systemic and local adipose tissue in knee osteoarthritis

Knee osteoarthritis (OA) is the most common joint disease. Body adipose tissue has been shown to be related to the development and progression of knee OA. Among systemic adipose tissues, subcutaneous adipose tissue is significantly and negatively associated with muscle mass and forces, and could be related to the presence and progression of knee OA. Visceral adipose tissue is associated with increased cartilage loss and production of pro-inflammatory cytokines. Intra-muscular adipose tissue is associated with knee osteoarthritic changes, but it remains controversial if inter-muscular adipose tissue has a role to play in the pathogenesis for knee OA. Knee local adipose tissue such as infrapatellar fat pad (IPFP) can interact with neighbouring tissues, and may have a biphasic effect in knee OA. The underlying mechanisms for the roles of the systemic and local fat in knee OA could be related to biomechanical, metabolic, inflammatory factors and fat fibrosis, which may have a separated or combined effect on OA. Tissue engineering from systemic or local adipose tissue is a new research direction, and adipose tissue-derived stem cells from systemic or local adipose tissue may be beneficial for OA cartilage repair. Research on systemic and local adipose tissue would provide novel approaches for prevention and treatment of knee OA, but further studies are required to explore the roles of different adipose tissues in knee OA and the effects of stem cells derived from different adipose tissues on knee OA.

The importance of synovial inflammation in osteoarthritis: current evidence from imaging assessments and clinical trials

Synovial abnormalities have been observed at multiple stages of osteoarthritis (OA). Increasing evidence suggests that it may play an important role in the OA pathological process. Many assessment systems using magnetic resonance imaging (MRI) and ultrasound have been established to detect synovial inflammation in OA. These have been used to inform the current investigation of OA disease phenotypes and progression and can be utilised in the future for clinical trials developing potential treatments. This narrative review aims to illustrate the importance of synovial tissue in OA and provide an overview of imaging assessments and possible therapies targeting synovial abnormalities.

Influence of low-protein and low-amino acid diets with different sources of protease on performance, carcasses and nitrogen retention of broiler chickens

A 42-day experiment was conducted with 625 1-day-old male Hubbard chickens to evaluate the performance, carcass traits, nitrogen retention and economics of broiler chickens fed low protein and amino acid diets supplemented with different protease sources. Treatments included positive (PC) and negative (NC) controls (PC at 19.3% protein vs NC at 18.8% protein), with NC containing 7% less digestible amino acids. The other three treatment groups were based on the NC diet supplemented with 0.05% Cibenza® DP100 (CB), 0.02% Ronozyme® (RZ) or 0.02% Winzyme pro plus (WZ). Birds fed the PC, CB and WZ diets achieved the heaviest bodyweight compared with those fed the NC diet at end of the experiment. Total feed intake of birds fed the PC diet was higher (P < 0.05) than that of birds fed the NC diet. Feed conversion ratio was numerically significantly (P = 0.005) improved with all tested groups in comparison with NC throughout the experiment. European production index was similar (P > 0.05) among birds fed the PC, NC, RZ or WZ diets. All carcass parameters studied, including dressing, heart, gizzard, giblets, chest meat, thigh meat and abdominal fat percentages, were not significantly (P > 0.05) affected by feeding on the different sources of protease. Broilers fed the PC diet or diets formulated with all protease sources had higher (P < 0.05) nitrogen retention than did birds fed the NC diet. The supplementation of protease to low-protein and low-amino acid diets resulted in higher profit margin in broilers. It is concluded that supplementing exogenous protease to broiler diets containing low protein and amino acids improved the growth performance, feed utilisation, carcass traits, nitrogen retention and net returns of broiler chickens.

Associations between MRI-detected early osteophytes and knee structure in older adults: a population-based cohort study

OBJECTIVES

To describe prevalence of osteophytes (OPs) detected only by magnetic resonance imaging (MRI) but not by standard X-ray in older adults and to evaluate longitudinal associations with knee structural changes.

METHODS

837 participants were randomly selected from the local community and had MRI scans to assess knee OPs and other structures. OPs detected only by MRI but not by standard X-ray were defined as MRI-detected early OPs (MRI-OPs for short). OPs detected by both MRI and X-ray were defined as established-OPs.

RESULTS

The prevalence of MRI-OPs was 50% while the prevalence of established-OPs was 10% and no-OPs was 40% at total tibiofemoral (TF) compartment at baseline. Compared with no-OPs, participants with MRI-OPs had greater risks of increased cartilage defects in all TF compartments (RR 1.37, 95%CI 1.07-1.74) and bone marrow lesions (BMLs) only in medial TF compartment (RR 1.49, 95%CI 1.06-2.11), after adjustment for age, sex, BMI, cartilage defects, BMLs and/or joint space narrowing; participants with established-OPs had greater cartilage volume loss at total (β -2.02, 95%CI -3.86, -0.17) and lateral tibial sites (β -5.63, 95%CI -9.93, -1.32), greater risks of increased cartilage defects in total (RR 1.66, 95%CI 1.15-2.40) and medial TF compartments (RR 1.49, 95%CI 1.20-1.69) and BMLs in all TF compartments (RR 1.88, 95%CI 1.22-2.89), after adjustment for covariates.

CONCLUSION

MRI-OPs were associated with changes in knee structures, and the associations were similar but not as prominent as those for established-OPs. These suggest MRI-OPs may have a role to play in knee early-stage osteoarthritic progression.

Associations between proximal tibiofibular joint (PTFJ) types and knee osteoarthritic changes in older adults

PURPOSE

To describe the cross-sectional associations between proximal tibiofibular joint (PTFJ) type configurations and knee joint structural abnormalities in older adults.

METHODS

A total of 967 community-based participants were studied. T1-weighted fat-suppressed magnetic resonance image (MRI) with spoiled gradient recalled echo sequence was utilized to assess the PTFJ type configurations. Knee cartilage volume, cartilage defects, bone marrow lesions and osteophytes were measured. Linear regression and binary logistic regression analyses were used to examine the associations between PTFJ type configurations and knee joint cartilage volume as well as knee structural abnormalities, respectively, after adjustment for potential confounders.

RESULTS

Seven PTFJ types including plane (49.4%), trochoid (31.9%), double trochoid (4.3%), saddle (5.4%), condylar (5.3%), trochlear (3.5%) and ball & socket (0.2%) were observed. Plane type was used as the comparator. In multivariable analyses, irregular joint types (comprising the five uncommon joint types) were associated negatively with cartilage volume, and positively with knee cartilage defects, bone marrow lesions and osteophytes in the lateral (but not medial) compartments. In contrast, trochoid type was only associated with reduced femoral cartilage volume, but not with knee cartilage defects, bone marrow lesions and osteophytes.

CONCLUSIONS

Irregular PTFJ joint shapes are associated with osteoarthritic changes in the lateral, but not medial, tibiofemoral compartment in older adults. The causal relationship needs to be examined in future longitudinal studies.

Associations between serum ghrelin and knee symptoms, joint structures and cartilage or bone biomarkers in patients with knee osteoarthritis

OBJECTIVE

The roles of ghrelin in knee osteoarthritis (OA) are unclear. This study aimed to examine cross-sectional associations of ghrelin with knee symptoms, joint structures and cartilage or bone biomarkers in patients with knee OA.

METHODS

This study included 146 patients with symptomatic knee OA. Serum levels of ghrelin and cartilage or bone biomarkers including cartilage oligomeric matrix protein (COMP), cross linked C-telopeptide of type I collagen (CTXI), cross linked N-telopeptide of type I collagen (NTXI), N-terminal procollagen III propeptide (PIIINP), and matrix metalloproteinase (MMP)-3, 10, 13 were measured using Enzyme-linked immunosorbent assay (ELISA). Knee symptoms were assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Infrapatellar fat pad (IPFP) volume, IPFP signal intensity alternation, cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis were assessed using the (MRI). Osteophytes and joint space narrowing (JSN) were assessed using the Osteoarthritis Research Society International atlas.

RESULTS

After adjustment for potential confounders, ghrelin quartiles were positively associated with knee symptoms including pain, stiffness, dysfunction and total score (quartile 4 vs 1: β 24.19, 95% CI 8.13-40.25). Ghrelin quartiles were also significantly associated with increased IPFP signal intensity alteration (quartile 4 vs 1: OR 3.57, 95% CI 1.55-8.25) and NTXI, PIIINP, MMP3 and MMP13. Ghrelin was not significantly associated with other joint structures and biomarkers.

CONCLUSIONS

Serum levels of ghrelin were significantly associated with increased knee symptoms, IPFP signal intensity alteration and serum levels of MMP3, MMP13, NTXI and PIIINP, suggesting that ghrelin may have a role to play in knee OA.

Knee effusion-synovitis volume measurement and effects of vitamin D supplementation in patients with knee osteoarthritis

OBJECTIVE

To develop a measure of knee joint effusion-synovitis volume and to examine the effect of vitamin D supplementation on effusion-synovitis in people with knee osteoarthritis (OA) and low vitamin D levels over 24 months.

METHOD

Symptomatic knee OA patients with low 25-(OH)D levels (12.5-60 nmol/l) were recruited for a multi-centre, randomised, placebo-controlled and double-blind trial. Participants (age 63 ± 7 years, 208 females) were allocated to either 50,000 IU monthly vitamin D₃ (n = 209) or placebo (n = 204) for 24 months. Knee effusion-synovitis volume in suprapatellar and other regions was measured on magnetic resonance imaging (MRI) using OsiriX software. The intra-class correlation coefficients (ICCs) were used to test inter- and intra-rater reliabilities. The least significant change criterion was used to define the increase/decrease in effusion-synovitis volume.

RESULT

The reproducibilities of effusion-synovitis volume measurement were high with ICCs ranging from 0.93 to 0.99. Over 24 months, effusion-synovitis volume remained stable in the vitamin D group but increased in placebos with a significant between-group difference (-1.94 ml, 95% confidence interval (CI): -3.54, -0.33). This effect was evident in those with baseline effusion-synovitis and with suprapatellar effusion-synovitis. The proportion with an increase in effusion-synovitis volume was lower in the vitamin D group than placebo (risk ratio (RR): 0.87, 95% CI: 0.77, 0.97).

CONCLUSION

This highly reproducible effusion-synovitis volume measurement could be a promising outcome measure in OA trials. Vitamin D supplementation could retard the progression of effusion-synovitis which can potentially benefit people with an inflammatory OA phenotype.

Comparison of vertical and horizontal swimming behaviour of the weather loach Misgurnus anguillicaudatus

Experiments on the swimming kinetics and behaviour of weather loach Misgurnus anguillicaudatus showed that horizontal swim speed was significantly greater than swim speeds when ascending to or descending from the water surface to gulp air. Vertical swimming speeds during ascending or descending were similar. Misgurnus anguillicaudatus swam unsteadily during vertical movements compared with horizontal movements.

Associations between endogenous sex hormones and MRI structural changes in patients with symptomatic knee osteoarthritis

OBJECTIVE

To investigate the longitudinal association between endogenous sex hormones and knee osteoarthritis (OA) structures and pain.

METHOD

We examined 200 participants (mean age 63.0 ± 7.3 years) from a clinical trial of vitamin D supplement for symptomatic knee OA. Serum levels of estradiol, progesterone, testosterone and sex hormone binding globulin (SHBG) were analyzed at baseline and 24 months later. Magnetic resonance imaging (MRI) scans of selected knee were obtained at both baseline and follow-up for the measurement of cartilage volume, cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis volume. Knee pain was assessed using a 100 mm visual analogue scale (VAS). Longitudinal data were analyzed using linear mixed-effects model.

RESULTS

One hundred and seven males and 93 females were included in this study. For females, after adjustment for age, body mass index (BMI), and vitamin D level, progesterone was positively associated with cartilage volume (β = 0.12 mm³ per quartile, P < 0.01). Estradiol levels were associated with lower grades of BMLs (β = -0.46 per quartile, P = 0.03), while estradiol (β = -1.28 per quartile, P = 0.04), progesterone (β = -1.56 per quartile, P < 0.01) and testosterone (β = -1.51 per quartile, P = 0.01) were inversely associated with effusion-synovitis volume. Testosterone was inversely associated with knee pain. No consistent associations were observed for males.

CONCLUSION

In women but not men, low serum levels of endogenous estradiol, progesterone and testosterone are associated with increased knee effusion-synovitis and possibly other OA-related structural changes. This may contribute to observed sex differences in knee OA.

Association between MRI-detected osteophytes and changes in knee structures and pain in older adults: a cohort study

OBJECTIVE

To describe cross-sectional and longitudinal associations between magnetic resonance imaging (MRI)-detected osteophytes (OPs) and knee structural abnormalities and knee pain in older adults.

METHOD

A prospective population-based cohort study of 895 participants aged 50-80 years (mean age 62 years, 50% female) was performed. T1-or T2-weighted fat suppressed MRI was used to assess knee OPs, cartilage volume, cartilage defects and bone marrow lesions (BMLs) at baseline and after 2.6 years. Radiographically-detected OPs were scored according to the Osteoarthritis Research Society International (OARSI) atlas. Knee pain was assessed using a self-administered questionnaire at baseline, 2.6 and 5 years later.

RESULTS

85% of participants had MRI-detected OPs at baseline, while 10% of participants had radiographically-detected OPs. Cross-sectionally, higher gardes of MRI-detected OPs in all compartments were significantly, independently and site-specifically associated with higher prevalences of cartilage defects and BMLs, lower cartilage volume and higher prevalence of knee pain. Longitudinally, higher gardes of baseline MRI-detected OPs site-specifically predicted greater risks of any increase in cartilage defects or BMLs, and loss of cartilage volume in medial and lateral tibiofemoral (LTF) and total compartments over 2.6 years in multivariable analyses. These significant associations were similar in those without radiographically-detected OPs. MTF and total OP scores were significantly associated with change in total knee pain over 2.6 and 5 years but these became non-significant after adjustment for cartilage defects and BMLs.

CONCLUSION

MRI-detected knee OPs are common and appear to be clinically relevant to knee structural changes in older adults.

Cross-sectional and longitudinal associations between serum inflammatory cytokines and knee bone marrow lesions in patients with knee osteoarthritis

OBJECTIVE

To describe cross-sectional and longitudinal associations between serum levels of interleukin (IL) - 6, IL-17A, IL-17F, IL-23 and knee bone marrow lesions (BMLs) in patients with knee osteoarthritis (OA).

DESIGN

Patients (n = 192) with symptomatic knee OA (mean 63 years, range 50-79, female 53%) were assessed at baseline and after 24 months. At each time point, serum IL-6, IL-17A, IL-17F and IL-23 were measured using Bio-Plex^® Multiplex Immunoassays with Luminex xMAP technology. Knee BMLs were scored using the modified whole organ MRI score (WORMS) from T2 weighted fat-suppressed fast spin echo magnetic resonance imaging (MRI). Multivariable linear regression and log binominal regression were used to determine the associations between cytokines and BMLs.

RESULTS

Baseline IL-6 (quarters) were significantly associated with total knee BMLs (P < 0.01 for the trend) as well as associated with an increase in BML score (P = 0.05 for the trend), after adjustment for confounders. Baseline IL-17F and IL-23 (highest quarters vs others) was associated with an increase in BML score in females (P = 0.04 for IL-17F; P = 0.01 for IL-23), but not in males, in multivariable analyses. In contrast, IL-17A was not significantly associated with BMLs in either females or males.

CONCLUSION

IL-6 is associated with increased knee BMLs in both females and males with OA. Serum IL-17F and IL-23 predicted increased knee BML scores in females only, suggesting that inflammation is involved in BML pathogenesis in knee OA, especially in women.

TRAIL REGISTRATION

ClinicalTrials.gov identifier: NCT01176344; Australian New Zealand Clinical Trials Registry: ACTRN12610000495022.

Test-retest reliability of measurements of abdominal and multifidus muscles using ultrasound imaging in adults aged 50-79 years

Test-retest reliability of the combined process of ultrasound imaging (USI) and image measurement of thickness of abdominal and upper lumbar multifidus (MF) muscles and MF cross sectional area (CSA) of older adults has not been established. Imaging muscles of older adults can be challenging due to age-related changes in the spine and skeletal muscle so establishing test-retest reliability in this population is important. This study aimed to evaluate test-retest reliability of USI of abdominal and MF muscle thickness and MF CSA for adults aged 50-79 years. One operator took single sets of ultrasound images of abdominal and MF muscles of 23 adults aged 50-79 years participating in a clinical trial of vitamin D supplementation for knee osteoarthritis, on two occasions, one week apart. Images were subsequently measured by a single examiner. Test-retest reliability for abdominal muscle thickness and MF CSA was substantial (intraclass correlation coefficients (ICC) > 0.81) and for MF thickness ranged from fair to substantial (ICC 0.55-0.86). The standard error of measurement (SEM) was low (0.02-0.21) in every case. ICCs were low and SEM values were high for percentage thickness change. The substantial test-retest reliability of abdominal and MF (L4-L5) muscle thickness and of MF CSA supports the use of USI as a clinical and research tool to assess abdominal and MF muscle thickness and MF CSA of older adults.

The interaction between weight and family history of total knee replacement with knee cartilage: a 10-year prospective study

OBJECTIVE

Although being overweight or obese is an important risk factor for the development of knee osteoarthritis (OA), the interplay between weight and genetic factors remains unclear. This study aimed to examine the associations between weight and knee cartilage volume/defects over 10 years in offspring having at least one parent with a total knee replacement (TKR) for primary knee OA and in controls without a knee OA family history.

METHOD

367 participants (183 offspring and 184 controls) aged from 26 to 61 years were recruited at baseline, and followed at 2 and 10 years later. T1-weighted magnetic resonance imaging (MRI) of the right knee was used to measure cartilage volume/defects at each time-point. Mixed-effects models were used with adjustment for potential confounders.

RESULTS

Study participants were middle-age adults (mean age 45 years, mean weight 77.5 kg at baseline). In multivariable analysis, increasing body weight was deleteriously associated with medial tibiofemoral cartilage volume (β = -0.28 ml, per 1 SD increase, 95% CI -0.49 to -0.07) and presence of medial tibiofemoral cartilage defects (RR = 1.27, per 1 SD increase, 95% CI 1.07 to 1.51) in offspring over 10 years. Similar associations were observed for lateral tibiofemoral cartilage volume (β = -0.19 ml, P = 0.059), and defects (RR = 1.24, P = 0.049). However, there were no statistically significant associations between weight and cartilage volume or defects in controls.

CONCLUSION

The adverse effects of increasing weight are stronger in the offspring of people with knee replacement for knee OA suggesting genetics-environment interaction with regard to overweight/obesity in the pathogenesis of knee OA particularly in the early stages.

[Salubrinal improves cardiac function in rats with heart failure post myocardial infarction through reducing endoplasmic reticulum stress-associated apoptosis]

OBJECTIVE

Endoplasmic reticulum (ER) stress plays an important role in ischemia-mediated cell death. The aim of the current study is to investigate the effects of salubrinal (Sal), a selective eIF2a dephosphorylation inhibitor, on heart failure rats and related mechanisms.

METHODS

Heart failure was induced by coronary artery ligation (MI) in adult male Sprague-Dawley rats. To ensure comparable MI sizes post coronary artery ligation on various groups, echocardiography examination was performed before and 30 minutes after ligation in MI groups. Then rats were randomly assigned to 4 groups: Sham group (n=12), MI group (n=10), MI plus vehicle injections group (DMSO group, n=12) and MI plus Sal injection group (Sal group, n=12). Sal (1 mg/kg) or DMSO was injected via the tail vein daily for the first 3 days (starting at 30 minutes after ligation of the left coronary artery), followed by subcutaneous injections twice per week for 8 weeks. Cardiac function was assessed by echocardiography and cell apoptosis assessed by flow cytometric analysis after 8 weeks. Protein and mRNA levels of ER stress markers were evaluated by immunohistochemistry and real time RT-PCR respectively.

RESULTS

Eight weeks later, LVEF was significantly higher, while LVESD and LVEDD values were significantly lower in Sal group compared to MI and DMSO groups (all P<0.05); LV/BW ratio was significantly higher in MI group than in Sham group ((2.30±0.40) mg/g vs.(1.78±0.31) mg/g, P<0.05), which was significantly reduced in Sal group ((1.88±0.25) mg/g), but not in DMSO group((2.25±0.36) mg/g, P<0.05 vs. MI). In addition, flow cytometric analysis showed that Sal treatment significantly reduced apoptosis but not necrosis in post MI. Immunohistochemistry and real time PCR analysis showed that the myocardial protein and mRNA expression of ER stress markers were significantly lower in Sal group than in MI group, myocardial caspase-12 expression was significantly upregulated in MI group and significantly reduced by Sal treatment.

CONCLUSIONS

Our results suggest that reduction of ER stress and myocardial apoptosis through inhibition of eIF2α dephosphorylation may serve as the potential mechanisms for the improved cardiac function and attenuated cardiac remodeling post Sal treatment in this heart failure rat model.

Outcomes of standard dose EC-MPS with low exposure to CsA in DCD renal transplantation recipients with DGF

AIMS

The lower limit of exposure to cyclosporine A (CsA) has not yet been established in donation after cardiac death (DCD) renal transplantation recipients with delayed graft function (DGF) receiving enteric-coated mycophenolate sodium (EC-MPS) therapy. Stable and adequate mycophenolic acid (MPA) dosing may facilitate lower CsA exposure after DCD renal transplantation in recipients with DGF without compromising safety.

METHODS

A 12-month, single-centre open-label prospective trial was performed in our centre. According to their DGF risk index using the previous DGF prediction models, we divided up the patients on oral CsA into either a DGF group (n = 26) and no DGF group (n = 48). All of the patients initially received the standard EC-MPS dosing (1440 mg/day). The initial dose of CsA in the low risk of DGF group was 4.5 mg/kg/day and in the high risk of DGF group was 2.5 mg/kg/day. Efficacy parameters, safety and tolerability were assessed over a 12-month study period.

RESULTS

The incidence of DGF was 18.5% in the 162 DCD recipients. Between the DGF group and the no DGF group, the 1-year patient survival and graft survival were not significantly different. The incidence of BPAR was higher in the DGF group (26.9% vs. 8.3%, p = 0.032). Most patients in the DGF group had recovery of renal function after 1 month. The adverse events between the two groups were not significantly different. The daily EC-MPS doses of the DGF group were significantly higher than the no DGF group before the 6-month follow-up period. There were no significant differences between the two groups regarding the mean AUC levels during the follow-up period.

CONCLUSIONS

These results show that low expose CsA with standard dosing of EC-MPS and thymoglobulin was efficacious, safe and well-tolerated in DCD renal transplant recipients with DGF in China. Furthermore, stable and adequate MPA exposure helped to reduce the dose of and exposure to CsA. Thus, this may lead to less-induced nephrotoxicity and better renal function recovery.

[A multi-center study on the long-term mortality and related risk factors in patients with chronic heart failure receiving resynchronization therapy]

Objective: To analyze long-term mortality and patients characteristics of cardiac resynchronization therapy (CRT) for patients with chronic heart failure. Methods: In-patients with chronic heart failure who received CRT in the three medical centers(Bethune International Peace Hospital, General Hospital of Shenyang Military Command of Chinese People's Liberation Army, and 251 Hospital of People's Liberation Army)from March 2001 to June 2013 were included.Mortality and related causes, echocardiographic parameters were analyzed. Results: A total of 200 patients were treated with CRT therapy (154 males, mean age (60.57±11.75) years), 59 cases suffered from ischemic cardiomyopathy (ICM), patients were followed up from 0.5 to 12 years.The all-cause mortality rate was 25.50% (51/200), 20 out of 59 (33.90%) ICM patients died, as compared with 31 deaths out of 141 (21.98%) in non-ischemic cardiomyopath (NICM) patients.Thirty-six patients died due to cardiac death (70.59%), in which sudden death occurred in 21 patients (41.18%). Non-cardiac death occurred in 13 patients (25.49%), two patients died due to unknown reasons (3.92%). Incidence of cardiac death was significantly higher than non-cardiac death (P<0.01). The main cause for cardiac death was NICM (28/36, 77.78%), while the main cause of non-cardiac death was ICM (11/13, 84.62%, P<0.01). Patients died due to cardiac death were younger (P<0.01) and had larger left atrial end-diastolic diameter (LAEDD) and left ventricular end-diastolic diameter (LVEDD) (P<0.01), lower left ventricular ejection fraction (LVEF)(P<0.05), higher pulmonary artery pressure(P<0.05) compared to patients with non-cardiac death.One hundred and fifty-two cases received CRT-P and 48 cases received CRT-D, there were no significant differences in gender, the course of heart failure, serum creatinine levels, pre-operative and post-operative QRS duration and so on between the CRT-P and CRT-D groups(all P>0.05). Eleven out of the 48 cases with CRT-D died during the following-up (21.57%) , while 40 out of 152 cases with CRT-P died (78.43%) during the following-up(χ²=3.13, P<0.01). The proportional mortality rate in cause of death in patients with CRT-D was non-cardiac while in those with CRT-P was cardiac (χ²=2.66, P<0.01), sudden death rate was also significantly higher in CRT-P group than in CRT-D group (χ²=2.16, P<0.01). By using single- and multiple-factor Cox regression analysis, age, disease course, pre-operation QRS duration and NYHA classification were predictors of cardiac death(all P<0.05). Conclusions: The all-cause mortality of CRT is 25.50% in this patient cohort, mortality rate was higher in ICM patients than in NICM patients.Sudden cardiac death rate was the highest mortality reason.The mortality rate of patients with CRT-P was significantly higher than in patients with CRT-D.In comparison with patients of non-cardiac death, patients of cardiac death had larger left atrium and left ventricle and worse heart function before CRT implantation.

A novel method for assessing signal intensity within infrapatellar fat pad on MR images in patients with knee osteoarthritis

PURPOSE

To assess reliability and validity of a semi-automated quantitative method to measure infrapatellar fat pad (IPFP) signal intensity in patients with knee osteoarthritis (OA).

METHODS

Hundred patients with knee OA were selected. Sagittal planes of fat-saturated T2-weighted images obtained on 1.5-T magnetic resonance imaging (MRI) were utilized to assess IPFP signal intensity using MATLAB. Knee structural abnormalities including cartilage defects, bone marrow lesions (BML) and radiographic OA (ROA) were evaluated. Clinical construct validity and concurrent validity were examined through describing associations of IPFP measurements with knee structural abnormalities and a semi-quantitative scoring method, respectively. The reliability was examined by calculating the intra- and inter-observer correlation coefficients.

RESULTS

Significantly positive associations were found between standard deviation of IPFP signal intensity [sDev (IPFP)], clustering factor (H) and all knee structural abnormalities. The volume of high signal intensity regions [Volume (H)] and the ratio of Volume (H) to volume of whole IPFP [Percentage (H)] were positively associated with cartilage defects and ROA, but not with BMLs. The median value [Median (H)] and upper quartile value [UQ (H)] of high signal intensity were only significantly associated with quartiles of cartilage defect score. Significant correlations were found between all quantitative measurements and semi-quantitative scores (All P < 0.001). Intraclass and interclass correlation coefficients for these quantitative measures were high (>0.90).

CONCLUSIONS

A novel and efficient method to segment IPFP and calculate its signal intensity on T2-weighted MRI images is documented. This method is reproducible, and has concurrent and clinical construct validity, but its predictive validity needs to be examined by future longitudinal studies.