Infrapatellar Fat Pad Signal Intensity Research Articles

Qualitative and Quantitative Measures in the Infrapatellar Fat Pad in Older Adults: Associations with Knee Pain, Radiographic Osteoarthritis, Kinematics, and Kinetics of the Knee

ObjectiveThe purpose of this study is to delineate cross-sectional associations between qualitative and quantitative measures of the infrapatellar fat pad (IPFP) and knee symptoms, structure, kinematics, and kinetics in older adults. MethodsNinety eligible subjects (90 knees, mean age 54.0 years, 68.9% female) were examined at our centre. We used T2-weighted fat-suppressed magnetic resonance imaging (MRI) to evaluate signal intensity alteration, maximum sagittal area, and depth of the IPFP. Symptomatic osteoarthritis (SOA) was a pain subscale score greater than 0 on the Western Ontario McMaster Osteoarthritis Index. A Kellgren-Lawrence grade ≥ 2 identified incident radiographic osteoarthritis (iROA). Three-dimensional gait data were employed to analyze knee joint kinematics and kinetics. Correlation and regression analyses assessed associations between IPFP measurements and SOA, iROA, kinematics, and kinetics. ResultsThere were strong and positive associations between IPFP signal intensity alteration and both SOA and iROA in multivariable regression analyses [OR (95% CI): 2.849 (1.440 to 5.636), 2.356 (1.236 to 4.492), respectively]. Conversely, a significant negative correlation was observed between IPFP maximum area and flexion angle [B (95%CI): -1.557 (-2.549 to -0.564)]. Moreover, adjusting for covariates did not reveal any significant correlation between IPFP parameters and other indicators (P > 0.05, respectively). ConclusionIPFP signal intensity alteration and area were associated with knee clinical symptoms, structural abnormalities, and flexion angle in adults over 40, respectively. These findings suggest that IPFP may be a crucial imaging biomarker in early and middle knee osteoarthritis.

Ultrasound assessment of the infrapatellar fat pad can detect Hoffa-synovitis in patients following anterior cruciate ligament reconstruction: A pilot study

IntroductionOsteoarthritis (OA) commonly occurs following anterior cruciate ligament reconstruction (ACLR), affecting over 50 % of patients within 10–15 years post-ACLR. The Hoffa-synovitis of the infrapatellar fat pad (IPFP) has been implicated as a major contributor to OA pathogenesis. While MRI is typically used to evaluate the IPFP, it is cost-prohibitive for routine screening. This study aimed to validate ultrasound as an alternative for detecting IPFP Hoffa-synovitis in participants post-ACLR. MethodsIn this cross-sectional study, 15 participants (18–35 years, 1–5 years post-ACLR) underwent two imaging sessions separated by one week. First, a standardized bilateral anterior knee ultrasound assessment was used to examine IPFP echo-intensity. Second, MRI scans of both knees were graded by a board-certified musculoskeletal radiologist for Hoffa-synovitis according to the Anterior Cruciate Ligament Osteoarthritis Score grading system. IPFP echo-intensity were quantified on each ultrasound image, and a limb symmetry index (LSI) was calculated to assess between-limb differences. We used an independent t-test and Cohen's d effect sizes to compare IPFP echo-intensity LSI between people with and without MRI-confirmed Hoffa-synovitis. ResultsFour of the 15 participants (27 %) exhibited MRI-confirmed Hoffa-synovitis. Significantly higher IPFP echo-intensity LSI values were found in participants with Hoffa-synovitis (32.1 ± 12.1 %) compared to those without (10.5 ± 10.4 %), confirming the ultrasound's ability to distinguish between the two groups (t = -3.44; p = 0.004; d = 2.01). DiscussionUltrasound detects bilateral IPFP signal intensity alterations in participants post-ACLR with MRI-confirmed Hoffa-synovitis. This work should be seen as a proof-of-concept, and further validation in a larger, more diverse sample is essential for verifying these results.

Quantitatively Measured Infrapatellar Fat Pad Signal Intensity Alteration is Associated with Joint Effusion-synovitis in Knee Osteoarthritis.

The objective of this study is to investigate whether quantitatively measured infrapatellar fat pad (IPFP) signal intensity alteration is associated with joint effusion-synovitis in people with knee osteoarthritis (OA) over two years. Among 255 knee OA patients, IPFP signal intensity alteration represented by four measurement parameters [standard deviation of IPFP signal intensity (IPFP sDev), upper quartile value of IPFP high signal intensity region (IPFP UQ (H)), ratio of IPFP high signal intensity region volume to whole IPFP volume (IPFP percentage (H)), and clustering factor of IPFP high signal intensity (IPFP clustering factor (H))] was measured quantitatively at baseline and two-year follow-up using magnetic resonance imaging (MRI). Effusion-synovitis of the suprapatellar pouch and other cavities were measured both quantitatively and semi-quantitatively as effusion-synovitis volume and effusion-synovitis score at baseline and two-year follow-up using MRI. Mixed effects models assessed the associations between IPFP signal intensity alteration and effusion-synovitis over two years. In multivariable analyses, all four parameters of IPFP signal intensity alteration were positively associated with total effusion-synovitis volume and effusion-synovitis volumes of the suprapatellar pouch and of other cavities over two years (all P＜0.05). They were also associated with the semi-quantitative measure of effusion-synovitis except for IPFP percentage (H) with effusion-synovitis in other cavities. Quantitatively measured IPFP signal intensity alteration is positively associated with joint effusion-synovitis in people with knee OA, suggesting that IPFP signal intensity alteration may contribute to effusion-synovitis and a coexistent pattern of these two imaging biomarkers could exist in knee OA patients.

Correlation between the Signal Intensity Alteration of Infrapatellar Fat Pad and Knee Osteoarthritis: A Retrospective, Cross-Sectional Study

Infrapatellar fat pad (IPFP) inflammation is a common pathological manifestation in knee osteoarthritis (OA). However, the significance of IPFP signal intensity alteration for clinical diagnosis and treatment of knee OA needs further research. We assessed IPFP signal intensity alteration (0-3), IPFP maximum cross-sectional area (CSA) and IPFP depth, meniscus injury, bone marrow edema, and cartilage injury from magnetic-resonance imaging (MRI) in 41 non-KOA patients (K-L grade 0 and grade I) and 68 KOA patients (K-L grade 2,3 and 4). We found that IPFP signaling was altered in all patients with KOA whose alteration was closely related to the K-L grading. We found that the IPFP signal intensity was increased in most OA patients, especially the ones in the late stage. There were significant differences in IPFP maximum CSA and IPFP depth between groups in KOA and non-KOA patients. Moreover, Spearman correlation analysis showed that IPFP signal intensity was moderately positively correlated with age, meniscal injury, cartilage injury, and bone marrow edema, and negatively correlated with height, while not correlated with visual analogue scale (VAS) scoring and body mass index (BMI). In addition, women have higher IPFP inflammation scores on MRI than men. In conclusion, IPFP signal intensity alteration is associated with joint damage in knee OA, which may have clinical significance for diagnosing and treating KOA.

Quantitative infrapatellar fat pad signal intensity alteration as an imaging biomarker of knee osteoarthritis progression

ObjectiveTo determine the association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with knee osteoarthritis (OA) progression.MethodThis study was performed based on the Foundation for the National Institutes of...

Longitudinal association of infrapatellar fat pad signal intensity alteration with biochemical biomarkers in knee osteoarthritis.

To explore the longitudinal association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with OA-related biomarkers. Eighteen OA-related biochemical biomarkers of 600 knee OA participants in the Foundation for the National Institutes of Health OA Biomarkers Consortium (FNIH) study were extracted. The quantitative IPFP signal intensity measures were acquired based on magnetic resonance imaging, including mean value [Mean (IPFP)] and standard deviation [sDev (IPFP)] of the whole IPFP signal intensity, median value [Median (H)] and upper quartile value [UQ (H)] of high signal intensity, the ratio of volume of high signal intensity to volume of whole IPFP signal intensity [Percentage (H)] and Clustering factor (H). The linear mixed-effect model was applied to determine the longitudinal associations between IPFP signal intensity alteration and biochemical biomarkers over 2 years. All IPFP measures except for Clustering factor (H) were positively associated with urine collagenase-cleaved type II collagen neoepitope (uC2C), urine C-terminal cross-linked telopeptide of type II collagen (uCTX-II), urine C-terminal cross-linked telopeptide of type I collagen-α (uCTX-Iα) and urine N-terminal cross-linked telopeptide of type I collagen (uNTX-I). Mean (IPFP), Median (H) and Percentage (H) were positively associated with the nitrated form of an epitope located in the triple helix of type II collagen (Coll2-1 NO2). Mean (IPFP), Median (H) and UQ (H) were positively associated with sCTX-I and uCTX-Iβ. Positive associations between sDev (IPFP), Percentage (H) and serum hyaluronic acid (sHA) were found. Our results suggest a role of IPFP signal intensity alteration in joint tissue remodelling on a molecular level.

Associations of serum citrate levels with knee structural changes and cartilage enzymes in patients with knee osteoarthritis.

The aim of this study was to investigate cross-sectional associations between serum levels of citrate and knee structural changes and cartilage enzymes in patients with knee osteoarthritis (OA). A total of 137 subjects with symptomatic knee OA (mean age 55.0years, range 34-74, 84% female) were included. Knee radiography was used to assess knee osteophytes, joint space narrowing (JSN) and radiographic OA assessed by Kellgren-Lawrence (K-L) grading system. T2-weighted fat-suppressed fast spin echo magnetic resonance imaging (MRI) was used to determine knee cartilage defects, bone marrow lesions (BMLs) and infrapatellar fat pad (IPFP) signal intensity alternations. Colorimetric fluorescence was used to measure the serum levels of citrate. Enzyme-linked immunosorbent assay was used to measure the serum cartilage enzymes including matrix metalloproteinase (MMP)-3 and MMP-13. After adjustment for potential confounders (age, sex, body mass index), serum citrate was negatively associated with knee osteophytes at the femoral site, cartilage defects at medial femoral site, total cartilage defects, and total BMLs (odds ratio [OR] 0.17-0.30, all P<.05). Meanwhile, serum citrate was negatively associated with IPFP signal intensity alteration (OR 0.30, P=.05) in multivariable analyses. Serum citrate was significantly and negatively associated with MMP-13 (β -3106.37, P<.05) after adjustment for potential confounders. However, citrate was not significantly associated with MMP-3 in patients with knee OA. Serum citrate was negatively associated with knee structural changes including femoral osteophytes, cartilage defects, and BMLs and also serum MMP-13 in patients with knee OA, suggesting that low serum citrate may be a potential indicator for advanced knee OA.

Association Between Quantitatively Measured Infrapatellar Fat Pad High Signal-Intensity Alteration and Magnetic Resonance Imaging-Assessed Progression of Knee Osteoarthritis.

To describe the cross-sectional and longitudinal associations between quantitative measures of infrapatellar fat pad (IPFP) signal-intensity alteration and knee structural abnormalities in patients with symptomatic knee osteoarthritis (OA). A total of 261 patients (mean ± SD age 63.0 ± 7.2 years) with symptomatic knee OA were selected from a randomized controlled trial with a follow-up of 2 years. IPFP signal-intensity alterations at baseline were quantitatively measured on T2-weighted fat-saturated magnetic resonance imaging using MATLAB. These quantitative measures included the SD of whole IPFP signal intensity measurement, the upper quartile value of high signal intensity (UQH ), the ratio of volume of high signal-intensity alteration to volume of whole IPFP (percentageH ), and the clustering effect of high signal intensity (clustering-factorH ). Cartilage volume and defects and bone marrow lesions (BMLs) were assessed using validated measures. Higher baseline SD of the IPFP, UQH , and clustering-factorH were associated with greater loss of tibial cartilage volume and larger increases in tibiofemoral cartilage defects over 2 years. Patients with high and medium tertiles of clustering-factorH had greater loss of cartilage volume per annum compared with those with a low tertile (for high 4.9%, for medium 4.6%, and for low 3.3% annually). Baseline percentageH and clustering-factorH were positively and significantly associated with increases in tibiofemoral BMLs over 2 years. Cross-sectional associations between IPFP measures and knee structures were similar but more consistent. Quantitative measures of increased signal intensity in the IPFP were associated with knee structural abnormalities in the tibiofemoral compartment, suggesting that these measurements could be used as an additional entry criterion to enrich studies for faster progressors of knee OA.

Quantitative Signal Intensity Alteration in Infrapatellar Fat Pad Predicts Incident Radiographic Osteoarthritis: The Osteoarthritis Initiative.

To determine whether infrapatellar fat pad (IPFP) signal intensity measures are predictive of incident radiographic osteoarthritis (ROA) over 4 years in the Osteoarthritis Initiative study. Case knees (n = 355), as defined by incident ROA, were matched 1:1 with control knees, according to sex, age, and radiographic status. T2-weighted magnetic resonance images were assessed at P0 (the visit when incident ROA was observed on a radiograph), P1 (1 year prior to P0), and baseline and used to assess IPFP signal intensity semiautomatically. Conditional logistic regression analyses were performed to assess the risk of incident ROA associated with IPFP signal intensity alteration, after adjustment for covariates. The mean age of the participants was 60.2 years, and most (66.7%) were female and overweight (mean body mass index 28.3 kg/m2 ). Baseline IPFP measures including the mean value and standard deviation of IPFP signal intensity, the mean value and standard deviation of IPFP high signal intensity, median and upper quartile values of IPFP high signal intensity, and the clustering effect of high signal intensity were associated with incident knee ROA over 4 years. All P1 IPFP measures were associated with incident ROA after 12 months. All P0 IPFP signal intensity measures were associated with ROA. The quantitative segmentation of high signal intensity in the IPFP observed in our study confirms the findings of previous work based on semiquantitative assessment, suggesting the predictive validity of semiquantitative assessment of IPFP high signal intensity. The IPFP high signal intensity alteration could be an important imaging biomarker to predict the occurrence of ROA.

Effusion-synovitis and infrapatellar fat pad signal intensity alteration differentiate accelerated knee osteoarthritis

To determine whether greater effusion-synovitis volume and infrapatellar fat pad (IFP) signal intensity alteration differentiate incident accelerated knee OA (KOA) from a gradual onset of KOA or no KOA. We classified three sex-matched groups of participants in the Osteoarthritis Initiative who had a knee with no radiographic KOA at baseline (recruited 2004-06; Kellgren-Lawrence <2; n = 125/group): accelerated KOA: ⩾1 knee progressed to Kellgren-Lawrence grade ⩾3 within 48 months; common KOA: ⩾1 knee increased in radiographic scoring within 48 months; and no KOA: both knees had the same Kellgren-Lawrence grade at baseline and 48 months. The observation period included up to 2 years before and after when the group criteria were met. Two musculoskeletal radiologists reported presence of IFP signal intensity alteration and independent readers used a semi-automated method to segment effusion-synovitis volume. We used generalized linear mixed models with group and time as independent variables, as well as testing a group-by-time interaction. Starting at 2 years before disease onset, adults who developed accelerated KOA had greater effusion-synovitis volume than their peers (accelerated KOA: 11.94 ± 0.90 cm3, KOA: 8.29 ± 1.19 cm3, no KOA: 8.14 ± 0.90 cm3) and have greater odds of having IFP signal intensity alteration than those with no KOA (odds ratio = 2.07, 95% CI = 1.14-3.78). Starting at 1 year prior to disease onset, those with accelerated KOA have greater than twice the odds of having IFP signal intensity alteration than those with common KOA. People with IFP signal intensity alteration and/or greater effusion-synovitis volume in the absence of radiographic KOA may be at high risk for accelerated KOA, which may be characterized by local inflammation.

Signal intensity alteration within infrapatellar fat pad predicts knee replacement within 5 years: data from the Osteoarthritis Initiative

To investigate whether infrapatellar fat pad (IPFP) signal intensity (SI) alteration predicts the occurrence of knee replacement (KR) in knee osteoarthritis (OA) patients over 5years. The subjects were selected from Osteoarthritis Initiative (OAI) study. Case knees (n=127) were defined as those who received KR during 5years follow-up visit. They were matched by gender, age and radiographic status with control knees (n=127). We used T2-weighted MR images to measure IPFP SI alteration using a newly developed algorithm in MATLAB. The measurements were assessed at baseline (BL), T0 (the visit just before KR) and 1year before T0 (T-1). Conditional logistic regression was used to analyse the associations between IPFP SI alterations and the risk of KR. Participants were mostly female (57%), with an average age of 63.7 years old and a mean body mass index (BMI) of 29.5kg/m2. In multivariable analysis, the standard deviation (SD) of IPFP SI [sDev (IPFP)] and the ratio of high SI region volume to whole IPFP volume [Percentage (H)] measured at BL were significantly associated with increased risks of KR after adjustment for covariates. IPFP SI alterations measured at T-1 including sDev (IPFP), Percentage (H) and clustering effect of high SI [Clustering factor (H)] were significantly associated with higher risks of KR. All measurements were significantly associated with higher risks of KR at T0. IPFP SI is associated with the occurrence of KR suggesting it may play a role in end-stage knee OA.

Associations between knee structural measures, circulating inflammatory factors and MMP13 in patients with knee osteoarthritis

To investigate cross-sectional associations between serum level of Matrix metalloproteinase (MMP)13 and knee structural measures and circulating inflammatory factors in patients with symptomatic knee osteoarthritis (OA). A total of 149 subjects with symptomatic knee OA were included. Magnetic resonance imaging was used to measure infrapatellar fat pad (IPFP) volume, IPFP signal intensity alternation, cartilage volume and cartilage defects. Knee radiography was used to assess radiographic OA using the Kellgren-Lawrence (K-L) grading system. Enzyme-linked immunosorbent assay was used to measure the serum levels of inflammatory factors and MMP13. In multivariable analyses, serum MMP13 was negatively associated with cartilage volume at patellar site (β:-32.94mm3 per 10ng/ml, P<0.05), and positively associated with cartilage defect at medial femoral site (OR: 1.13 per 10ng/ml, P<0.05). Also, MMP13 was positively associated with K-L grading and IPFP signal intensity alteration (OR: 1.14 and 1.15 per 10ng/ml, respectively, both P<0.05), and negatively associated with IPFP volume (β:-0.34cm3 per 10ng/ml, P<0.05). Furthermore, serum level of adiponectin was negatively associated serum MMP13 quartiles (OR: 0.66 per 10μg/ml, P<0.05), and serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-8 and IL-18 were positively associated with serum MMP13 quartiles (ORs: 1.01-1.18 per 10pg/ml, all P<0.05). Serum level of MMP13 was associated with knee structural abnormalities as well as serum inflammatory factors. These suggest that systemic MMP13 may play a role in knee OA, and could be regulated by inflammatory factors.

Validity of Radiograph-Based Infrapatellar Fat Pad Opacity Grading for Assessing Knee Synovitis: Correlation With Contrast-Enhanced MRI.

The purpose of this study was to determine the validity of infrapatellar fat pad (IPFP) opacity grading based on lateral knee radiography for assessing knee synovitis using correlation with contrast-enhanced (CE) MRI. Retrospective reviews of radiographs and CE knee MR images from 79 patients were independently performed by two radiologists. They evaluated IPFP opacity alteration (IPFPCR) and joint effusion grades on lateral knee conventional radiographs, IPFP signal intensity alteration (IPFPMR) and joint effusion grades on CE MR images, and synovitis (SYNMR) grade in nine divided regions, three compartments (parapatellar, periligamentous, perimeniscal), and the whole knee on CE MR images. Correlations between radiographic grades and MRI assessments were evaluated using Spearman correlation tests, and the correlation coefficients (ρ) were compared. Interobserver agreement was evaluated using weighted kappa values. The IPFPCR grade was very highly correlated with the IPFPMR grade (ρ = 0.906, p < 0.001) and highly correlated with SYNMR grades from four regions (suprapatellar, infrapatellar, intercondylar, lateral parapatellar recess), the parapatellar compartment, and the whole knee (ρ = 0.614-0.740, all p < 0.001). The IPFPCR grade was moderately correlated with the SYNMR grades of the remaining five regions and two compartments (ρ = 0.457-0.547, all p < 0.001). The differences between correlation coefficients for SYNMR grades and the IPFPCR and IPFPMR grades were not statistically significant (p = 0.290-1.0). Interobserver reliabilities were excellent or good for IPFPCR, IPFPMR, and SYNMR grades (κ = 0.661-1.000). IPFPCR grade assessment enables valid evaluation and reporting of knee synovitis, especially in the parapatellar compartment and the whole knee.

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

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. 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. 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. 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.

Assessment of anterior subcutaneous hypersignal on proton-density-weighted MR imaging of the knee and relationship with anterior knee pain

The purpose of this study was to evaluate the prevalence of anterior subcutaneous hypersignal indicating edema on proton-density (PD)-weighted MRI of the knee and to determine whether reporting anterior edema is clinically relevant. One hundred and ninety-one knee MRIs from 162 patients were reviewed for anterior subcutaneous edema. There were 92 men and 70 women with a mean age of 41.72years±13.92 (SD) (range, 15-80years) years and a mean body weight of 75.94kg±12.54 (SD) (range, 50-130kg). The MRI findings were compared with patient age, gender, body weight, history of repetitive microtrauma and clinical findings. Patellar and trochlear chondropathy, medial plica, joint effusion, synovitis, infrapatellar fat-pad signal intensity, suprapatellar fat-pad signal intensity with mass effect, quadriceps and patellar tendon abnormalities were also reviewed. An anterior hypersignal on PD-weighted MRI was detected in 158/191 MR examinations (82.7%) and 104 (84.6%) of these cases had histories of anterior knee pain. No correlation between anterior pain and anterior edema was found (P=0.42). Age (P<0.0001), weight (P<0.0001), and repetitive microtrauma (P=0.001) were identified as significant variables associated with anterior edema. Anterior edema may be a physiological phenomenon or degenerative change related to patient age, weight, and knee movement or mechanics. It should not be reported as a pathological finding on MRI unless clinical findings support regional infection or inflammation.

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

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). 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. 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). 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.

Signal intensity alteration in the infrapatellar fat pad at baseline for the prediction of knee symptoms and structure in older adults: a cohort study

ObjectiveTo describe the associations between infrapatellar fat pad (IPFP) signal intensity alteration at baseline and knee symptoms and structural changes in older adults.MethodsA total of 874 subjects (mean 62.1 years,...