Quantifying Complex Micro-Topography of Degenerated Articular Cartilage Surface by Contrast-Enhanced Micro-Computed Tomography and Parametric Analyses.

One of the earliest changes in osteoarthritis (OA) is a surface discontinuity of the articular cartilage (AC), and these surface changes become gradually more complex with OA progression. We recently developed a contrast enhanced micro-computed tomography (μCT) method for visualizing AC surface in detail. The present study aims to introduce a μCT analysis technique to parameterize these complex AC surface features and to demonstrate the feasibility of using these parameters to quantify degenerated AC surface.

3D morphometric analysis of calcified cartilage properties using micro-computed tomography.

Objective: Our aim is to establish methods for quantifying morphometric properties of calcified cartilage (CC) from micro-computed tomography (μCT). Furthermore, we evaluated the feasibility of these methods in investigating relationships between osteoarthritis (OA), tidemark surface morphology and open subchondral channels (OSCCs).

Method: Samples (n = 15) used in this study were harvested from human lateral tibial plateau (n = 8).

3D histopathological grading of osteochondral tissue using contrast-enhanced micro-computed tomography.

Objective: Histopathological grading of osteochondral (OC) tissue is widely used in osteoarthritis (OA) research, and it is relatively common in post-surgery in vitro diagnostics. However, relying on thin tissue section, this approach includes a number of limitations, such as: (1) destructiveness, (2) sample processing artefacts, (3) 2D section does not represent spatial 3D structure and composition of the tissue, and (4) the final outcome is subjective. To overcome these limitations, we recently developed a contrast-enhanced μCT (CEμCT) imaging technique to visualize the collagenous extracellular matrix (ECM) of articular cartilage (AC).

Pilot study on F-FDG PET/CT for detection of inflammatory changes in blood-induced knee arthropathy in a rabbit model.

Rationale: F-FDG-PET/CT has a potential role in the early detection of haemophilic arthritis, at a time when treatment may still avoid further joint degeneration. The purposes of this pilot study were to determine the ability of F-FDG-PET/CT to detect inflammatory changes associated with blood-induced arthropathy in knees of a rabbit model.

Methods: Ten juvenile rabbits were imaged at baseline and weeks 5 and 17 post intraarticular autologous blood injections (ABI).

USPIO-related T1 and T2 mapping MRI of cartilage in a rabbit model of blood-induced arthritis: a pilot study.

Ultrasmall paramagnetic iron oxide (USPIO)-enhanced MRI is promising for evaluating inflammation. The aims of this study were to investigate the effect of USPIO on cartilage T1 and T2 mapping, and to evaluate a proposed rapid vs. conventional T2 map method for imaging cartilage in a blood-induced arthritis model.

Systematic protocol for assessment of the validity of BOLD MRI in a rabbit model of inflammatory arthritis at 1.5 tesla.

Background: Blood-oxygen-level-dependent (BOLD) MRI has the potential to identify regions of early hypoxic and vascular joint changes in inflammatory arthritis. There is no standard protocol for analysis of BOLD MRI measurements in musculoskeletal disorders.

Objective: To optimize the following BOLD MRI reading parameters: (1) statistical threshold values (low, r > 0.

Effect of exercise on articular cartilage.

This review primarily focuses on how the macromolecular composition and architecture of articular cartilage and its unique biomechanical properties play a pivotal role in the ability of articular cartilage to withstand mechanical loads several magnitudes higher than the weight of the individual. Current findings on short-term and long-term effects of exercise on human articular cartilage are reviewed, and the importance of appropriate exercises for individuals with normal and diseased or aberrated cartilage is discussed.

Articular cartilage development: a molecular perspective.

In this article, development of articular cartilage and endochondral ossification is reviewed, from the perspective of both morphologic aspects of histogenesis and molecular biology, particularly with respect to key signaling molecules and extracellular matrix components most active in cartilage development. The current understanding of the roles of transforming growth factor β and associated signaling molecules, bone morphogenic proteins, and molecules of the Wnt-β catenin system in chondrogenesis are described. Articular cartilage development is a highly conserved complex biological process that is dynamic and robust in nature, which proceeds well without incident or failure in all joints of most young growing individuals.

Correlative BOLD MR imaging of stages of synovitis in a rabbit model of antigen-induced arthritis.

Background: Because of the ability of blood-oxygen-level-dependent (BOLD) MRI to assess blood oxygenation changes within the microvasculature, this technique holds potential for evaluating early perisynovial changes in inflammatory arthritis.

Objective: To evaluate the feasibility of BOLD MRI to detect interval perisynovial changes in knees of rabbits with inflammatory arthritis.

Materials And Methods: Rabbit knees were injected with albumin (n=9) or saline (n=6) intra-articularly, or were not injected (control knees, n=9).

Imaging of SHOX-associated anomalies.

Human growth is a multifactorial trait influenced by environmental, hormonal, and genetic factors. Although it is clear that multiple factors contribute to an individual's final height and limb development, genetic factors play a crucial role. One such gene is the short stature homeobox ( SHOX) containing gene.

Magnetic resonance imaging characterization of osteochondral defect repair in a goat model at 8 T.

Objective: This study was performed to non-invasively visualize and characterize osteochondral (OC) repair in ex vivo goat stifles using an 8 T magnetic resonance imaging (MRI) scanner and to compare the MR morphology with images obtained from 1.5 T, gross morphology and histology.

Methods: Mature, neutered male goats were assigned to an 8-week (n = 4) or 16-week (n = 4) study period.

Pulmonary thromboembolism in children.

Pulmonary thromboembolism (PTE) is uncommonly diagnosed in the pediatric patient, and indeed often only discovered on autopsy. The incidence of pediatric PTE depends upon the associated underlying disease, diagnostic tests used, and index of suspicion. Multiple risk factors can be found including: peripartum asphyxia, dyspnea, haemoptysis, chest pain, dehydration, septicemia, central venous lines (CVLs), trauma, surgery, ongoing hemolysis, vascular lesions, malignancy, renal disease, foreign bodies or, uncommonly, intracranial venous sinus thrombosis, burns, or nonbacterial thrombotic endocarditis.

Severe acute respiratory syndrome (SARS): chest radiographic features in children.

Background: Severe acute respiratory syndrome (SARS) is a recently recognized condition of viral origin associated with substantial morbidity and mortality rates in adults. Little information is available on its radiologic manifestations in children.

Objective: The goal of this study was to characterize the radiographic presentation of children with SARS.

Novel fluorescent compound (DDP) in calf, rabbit, and human articular cartilage and synovial fluid.

Objective: To investigate the presence of and quantify 2,6-dimethyldifuro-8-pyrone (DDP), a novel fluorescent compound identified as in various calf, rabbit, and human tissue/fluid samples, to determine the DDP level in articular cartilage (AC) laminae, and to investigate the changes in cartilage DDP content with cartilage maturation.

Methods: Samples were obtained from calf (< 2 years), rabbit (< 2 weeks to 2 years) or human AC and synovial fluid (SF) as well as other non-cartilaginous tissues. SF and tissue samples were hydrolyzed with 6 M HCl (24 hours at 110 degrees C), lyophilized, and dissolved in HPLC mobile phase.

A cartilage derived novel compound DDP (2,6-dimethyldifuro-8-pyrone): isolation, purification, and identification.

Objective: Fluorescent biomolecules within cartilage matrix can be used as specific markers of cartilage metabolism. While establishing the protocol to evaluate mature collagen crosslinks in articular cartilage (AC) associated with maturation, aging, and osteoarthritis, chromatographic analysis of the crosslinks also revealed an apparently novel fluorescent peak. Preliminary investigation of this compound (now abbreviated DDP) in various tissues from rabbits, calves, chickens, and humans showed that this compound is AC-specific.

MRI of the cartilaginous epiphysis of the femoral head in the piglet hip after ischemic damage.

MRI of the cartilaginous epiphysis (CE) of piglet femoral head was performed after ischemic damage to study the changes in the CE found on MRI and to correlate these changes with histologic findings. Avascular necrosis of the femoral head was induced with a suture ligature in nine piglets; one piglet was killed postoperatively on day 3 and on weeks 1, 2, 3, 4, 6, 7, and 8 (two piglets were killed on week 3). MRI of the ischemic and contralateral nonischemic hip joints were obtained with a 60-mm field of view (low resolution MRI).

High-resolution magnetic resonance imaging of normal porcine cartilaginous epiphyseal maturation.

The aim of this study was to determine whether high-resolution magnetic resonance (MR) imaging could differentiate epiphyseal and articular cartilage in the cartilaginous epiphysis and demonstrate its developmental changes. T1- and T2-weighted (T1W and T2W) spin-echo sequences at 50-mm field of view (FOV) of hip joints were obtained from 14 piglets (newborn to 6 months). Subsequently, high-resolution MR images (15-mm FOV) of a biopsy core of the proximal femoral cartilaginous epiphysis were correlated with histology.

Imaging of immature articular cartilage using ultrasound backscatter microscopy at 50 MHz.

A high frequency sonographic technique-ultrasound backscatter microscopy-was used to visualize the subsurface structure of immature porcine articular cartilage from the knee joint. In 20-week-old pigs, all parts that were scanned, except the weight-bearing regions of the femoral condyles, demonstrated heterogeneous ultrasound backscatter characteristics within the articular cartilage. A trilaminar pattern consisting of hypoechoic, hyperechoic, and anechoic layers ranging from superficial to deep generally was observed, except in the weight-bearing regions of the femoral condyles, where a homogeneous anechoic pattern was seen.

Osteoarthritis staging: comparison between magnetic resonance imaging, gross pathology and histopathology in the rhesus macaque.

Although osteoarthritis (OA) is the most common cause of articular skeletal disability in humans, assessing progression (staging) with noninvasive methods remains a major clinical problem. Using the rhesus macaque animal model, the objective of this study was to compare OA staging by noninvasive magnetic resonance imaging (MRI) against gross pathology and histopathology. Right knee joints from 18 rhesus macaques were used in this study.

Osteoarthritis in rhesus macaque knee joint: quantitative magnetic resonance imaging tissue characterization of articular cartilage.

Objective: To assess cartilage matrix quality variation by anatomical location and extent of osteoarthritis (OA) using quantitative magnetic resonance imaging (MRI) and to compare the anatomic MR morphologic features with corresponding histological findings.

Methods: We studied 18 fully encapsulated right knee joints from a population of rhesus monkeys with a high incidence of degenerative arthritis resembling human OA. Relaxation times (T1 and T2) spin density, and cartilage thickness were determined along 8 contiguous anteroposterior segments of articular cartilage.

Analysis of collagens solubilized from cartilage of normal and spontaneously osteoarthritic rhesus monkeys.

Osteoarthritis (OA) is a disorder which results in the destruction of the articular cartilage and the remodeling of the subchondral bone in synovial joints. We have analyzed the cartilage collagen from normal and osteoarthritic free-ranging rhesus monkeys from the Cayo Santiago colony. The cartilage samples were assigned a severity score based on histological staging system and were divided into four groups (normals, mild OA, moderate OA and severe OA).

Osteoarthritis in rhesus macaques: assessment of cartilage matrix quality by quantitative magnetic resonance imaging.

To assess cartilage quality with anatomical location and extent of osteoarthritis (OA), magnetic resonance imaging (MRI) of the knee joint from rhesus monkeys was performed. MRI measurements--T1 and T2 relaxation times, proton density and cartilage thickness were taken from 8 equal segments of articular cartilage volumes extending from anterior to posterior edge of 1 mm sagittal slices. To grade the severity of OA in each quadrant of the knee joint a modified Mankin score was applied on the histological sections.