Jukka Jurvelin - Academia.edu (original) (raw)

Papers by Jukka Jurvelin

Scientific Reports, Nov 26, 2018

Journal of Orthopaedic Research

Cationic computed tomography contrast agents are more sensitive for detecting cartilage degenerat... more Cationic computed tomography contrast agents are more sensitive for detecting cartilage degeneration than anionic or non‐ionic agents. However, osteoarthritis‐related loss of proteoglycans and increase in water content contrarily affect the diffusion of cationic contrast agents, limiting their sensitivity. The quantitative dual‐energy computed tomography technique allows the simultaneous determination of the partitions of iodine‐based cationic (CA4+) and gadolinium‐based non‐ionic (gadoteridol) agents in cartilage at diffusion equilibrium. Normalizing the cationic agent partition at diffusion equilibrium with that of the non‐ionic agent improves diagnostic sensitivity. We hypothesize that this sensitivity improvement is also prominent during early diffusion time points and that the technique is applicable during contrast agent diffusion. To investigate the validity of this hypothesis, osteochondral plugs (d = 8 mm, N = 33), extracted from human cadaver (n = 4) knee joints, were imme...

Scientific Reports, 2019

Early diagnosis of acute cartilage injuries enables monitoring of disease progression and improve... more Early diagnosis of acute cartilage injuries enables monitoring of disease progression and improved treatment option planning to prevent post-traumatic osteoarthritis. In contrast-enhanced computed tomography (CECT), the changes in cationic agent diffusion within the tissue reflect cartilage degeneration. The diffusion in degenerated cartilage depends on proteoglycan (PG) content and water content, but each having an opposite effect on diffusion, thus compromising the diagnostic sensitivity. To overcome this limitation, we propose the simultaneous imaging of cationic (sensitive to PG and water contents) and non-ionic (sensitive to water content) agents. In this study, quantitative dual-energy CT (QDECT) imaging of two agents is reported for the first time at clinically feasible imaging time points. Furthermore, this is the first time synchrotron microCT with monochromatic X-rays is employed in cartilage CECT. Imaging was conducted at 1 and 2 h post contrast agent immersion. Intact, P...

Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2019

Radiological and pathological characteristics of hip osteoarthritis (OA) is joint-space loss due ... more Radiological and pathological characteristics of hip osteoarthritis (OA) is joint-space loss due to degradation of articular cartilage. However, patients with early-stage OA do not yet show any radiological signs, which leaves them without diagnosis and treatment. This study evaluates the potential of a novel tool to identify pre-radiographic OA changes based on hip bone morphology. Two statistical appearance models for femur and pelvis were used to estimate the 3Dmorphology of the hip bones based on planar radiographs from patients. Well-known hip geometrical parameters (n = 22) were computed from patient CT scans (truth), 3D reconstructions (new method) and radiographs (calculated manually). The methods were compared by measuring relative error to truth. The new method was significantly more accurate in calculating hip geometrical parameters than the manual 2D calculations. The proposed approach could also capture rotational parameters like cross-over sign and anterior wall sign (100% correct predictions). The method can successfully reconstruct 3D hip shapes and densities for patients that have not yet developed severe osteoarthritis, and provided higher precision than manual estimations. Thus, it may be used to calculate morphological parameters that are predictors of OA and can become a powerful tool in human hip OA research and diagnostics.

Bone reports, 2017

The cortical characteristics of the iliac crest in male have rarely been investigated with quanti... more The cortical characteristics of the iliac crest in male have rarely been investigated with quantitative histomorphometry. Also it is still unknown how cortical microarchitecture may vary between the iliac crest and fractures related sites at the proximal femur. We studied the microarchitecture of both external and internal cortices within the iliac crest, and compared the results with femoral neck and subtrochanteric femoral shaft sites. Undecalcified histological sections of the iliac crest were obtained bicortically from cadavers (n = 20, aged 18-82 years, males). They were cut (7 μm) and stained using modified Masson-Goldner stain. Histomorphometric parameters of cortical bone were analysed with low (× 50) and high (× 100) magnification, after identifying cortical bone boundaries using our previously validated method. Within cortical bone area, only complete osteons with typical concentric lamellae and cement line were selected and measured. At the iliac crest, the mean cortical ...

Biomechanics and modeling in mechanobiology, Jun 21, 2016

Computed tomography (CT)-based finite element (FE) models may improve the current osteoporosis di... more Computed tomography (CT)-based finite element (FE) models may improve the current osteoporosis diagnostics and prediction of fracture risk by providing an estimate for femoral strength. However, the need for a CT scan, as opposed to the conventional use of dual-energy X-ray absorptiometry (DXA) for osteoporosis diagnostics, is considered a major obstacle. The 3D shape and bone mineral density (BMD) distribution of a femur can be reconstructed using a statistical shape and appearance model (SSAM) and the DXA image of the femur. Then, the reconstructed shape and BMD could be used to build FE models to predict bone strength. Since high accuracy is needed in all steps of the analysis, this study aimed at evaluating the ability of a 3D FE model built from one 2D DXA image to predict the strains and fracture load of human femora. Three cadaver femora were retrieved, for which experimental measurements from ex vivo mechanical tests were available. FE models were built using the SSAM-based ...

Journal of Osteoporosis, 2016

In long-term prospective studies, dual-energy X-ray absorptiometry (DXA) devices need to be inevi... more In long-term prospective studies, dual-energy X-ray absorptiometry (DXA) devices need to be inevitably changed. It is essential to assess whether systematic differences will exist between measurements with the new and old device. A group of female volunteers (21–72 years) underwent anteroposterior lumbar spine L2–L4 (n=72), proximal femur (n=72), and total body (n=62) measurements with the Prodigy and the iDXA scanners at the same visit. The bone mineral density (BMD) measurements with these two scanners showed a high linear association at all tested sites (r=0.962–0.995;p<0.0001). The average iDXA BMD values were 1.5%, 0.5%, and 0.9% higher than those of Prodigy for lumbar spine (L2–L4) (p<0.0001), femoral neck (p=0.048), and total hip (p<0.0001), respectively. Total body BMD values measured with the iDXA were −1.3% lower (p<0.0001) than those measured with the Prodigy. For total body, lumbar spine, and femoral neck, the BMD differences as measured with these two device...

Journal of Biomechanical Engineering, 2016

In finite-element (FE) models of the knee joint, patella is often omitted. We investigated the im... more In finite-element (FE) models of the knee joint, patella is often omitted. We investigated the importance of patella and quadriceps forces on the knee joint motion by creating an FE model of the subject's knee. In addition, depthwise strains and stresses in patellar cartilage with different tissue properties were determined. An FE model was created from subject's magnetic resonance images. Knee rotations, moments, and translational forces during gait were recorded in a motion laboratory and used as an input for the model. Three material models were implemented into the patellar cartilage: (1) homogeneous model, (2) inhomogeneous (arcadelike fibrils), and (3) random fibrils at the superficial zone, mimicking early stages of osteoarthritis (OA). Implementation of patella and quadriceps forces into the model substantially reduced the internal–external femoral rotations (versus without patella). The simulated rotations in the model with the patella matched the measured rotations...

Journal of biomechanics, Jan 18, 2016

Subject-specific finite element models have been proposed as a tool to improve fracture risk asse... more Subject-specific finite element models have been proposed as a tool to improve fracture risk assessment in individuals. A thorough laboratory validation against experimental data is required before introducing such models in clinical practice. Results from digital image correlation can provide full-field strain distribution over the specimen surface during in vitro test, instead of at a few pre-defined locations as with strain gauges. The aim of this study was to validate finite element models of human femora against experimental data from three cadaver femora, both in terms of femoral strength and of the full-field strain distribution collected with digital image correlation. The results showed a high accuracy between predicted and measured principal strains (R(2)=0.93, RMSE=10%, 1600 validated data points per specimen). Femoral strength was predicted using a rate dependent material model with specific strain limit values for yield and failure. This provided an accurate prediction ...

Medical Image Analysis, 2015

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  3D shape, vBMD and FE mesh of the proximal femur were reconstructed from a DXA image  Surface reconstruction error was 1.0-1.4mm  Use of DXA, instead of projected CT images, had no significant effect on the reconstruction accuracy  DXA-based FE agreed well with CT-based FE analysis (stiffness r 2 =0.85, MAC=0. 0.977)  DXA-based FE analysis may help to simulate patient-specific bone mechanics

ASME 2011 Summer Bioengineering Conference, Parts A and B, 2011

Journal of osteoporosis, Jan 22, 2010

Aim was to investigate fracture risk (FR) according to bone loss (BL) rate. A random sample of 16... more Aim was to investigate fracture risk (FR) according to bone loss (BL) rate. A random sample of 1652 women aged 53.5 years was measured with dual X-ray absorptiometry in femoral neck in 1989 and 1994 and divided into tertiles of annual BL rate: high >0.84%, moderate 0.13%-0.84%, and low <0.13%. Low trauma energy fractures during following 10 years were recorded. There were no differences in FR between BL tertiles in Cox regression model. Factors predicting lower FR in Cox model were in high tertile: high T-score (HR 0.71; 95% CI 0.54-0.93, P = .012), no sister's fracture (HR 0.35; 0.19-0.64, P = .001), no mother's fracture (HR 0.52; 0.31-0.88, P = .015), in moderate tertile: high T-score (HR 0.69;0.53-0.91, P = .008) and good grip strength (HR 0.98; 0.97-0.99, P = .022). In low tertile there were no predictors for FR. BL predicted FR in women with mother's fracture in univariate and multivariate model (OR 2.6; 1.15-5.7, P = .021) but with sister's fracture this ...

Ultrasound in medicine & biology, 2009

The composition of bone marrow is influenced by many factors, such as age and diseases. The prese... more The composition of bone marrow is influenced by many factors, such as age and diseases. The present numerical study investigates the contribution of marrow on the acoustic measurements of trabecular bone. Cylindrical bone samples (n = 11), extracted from three anatomical sites of human cadaver knees, were imaged with a high-resolution microtomography (microCT). Three-dimensional finite difference time domain (FDTD) models (Wave 3000 Pro 2.2, Cyberlogic Inc., NY, USA) were created using the segmented microCT images of each sample. First, we evaluated the effect of voxel size on the computer resource requirements, morphological parameters and acoustic simulations. Second, the effect of bone marrow on ultrasonic measurements was assessed. The simulations were repeated with two voxel sizes before and after substitution of bone marrow (i.e., fat) with water. The voxel size of the FDTD mesh controlled the fine structure of the modeled calcified matrix and significantly affected the simula...

Osteoarthritis and Cartilage, 2015

Objective: To quantify early osteoarthritic-like changes in the structure and volume of subchondr... more Objective: To quantify early osteoarthritic-like changes in the structure and volume of subchondral bone plate and trabecular bone and properties of articular cartilage in a rabbit model of osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT). Methods: Left knee joints from eight skeletally mature New Zealand white rabbits underwent ACLT surgery, while the contralateral (CTRL) right knee joints were left unoperated. Femoral condyles were harvested 4 weeks after ACLT. Micro-computed tomography imaging was applied to evaluate the structural properties of subchondral bone plate and trabecular bone. Additionally, biomechanical properties, structure and composition of articular cartilage were assessed. Results: As a result of ACLT, significant thinning of the subchondral bone plate (P < 0.05) was accompanied by significantly reduced trabecular bone volume fraction and trabecular thickness in the medial femoral condyle compartment (P < 0.05), while no changes were observed in the lateral compartment. In both lateral and medial femoral condyles, the equilibrium modulus and superficial zone proteoglycan (PG) content were significantly lower in ACLT than CTRL joint cartilage (P < 0.05). Significant alterations in the collagen orientation angle extended substantially deeper into cartilage from the ACLT joints in the lateral femoral condyle relative to the medial condyle compartment (P < 0.05). Conclusions: In this model of early OA, significant changes in volume and microstructure of subchondral bone plate and trabecular bone were detected only in the femoral medial condyle, while alterations in articular cartilage properties were more severe in the lateral compartment. The former finding may be associated with reduced joint loading in the medial compartment due to ACLT, while the latter finding reflects early osteoarthritic changes in the lateral compartment.

Dual Energy X-Ray Absorptiometry, 2012

Physics in Medicine and Biology, 2009

Osteoporosis International, 2003

In the present study we evaluated the risk factors associated with peri-and postmenopausal bone l... more In the present study we evaluated the risk factors associated with peri-and postmenopausal bone loss and the effect of hormone replacement therapy (HRT) on weight-loss-related bone loss. The study population, 940 peri-and postmenopausal women, was selected from a random sample (n = 2025) of the OSTPRE study cohort (n = 13 100) in Kuopio, Finland. Bone mineral density (BMD; g/cm 2) at the lumbar spine and femoral neck, and body weight, were measured at baseline in 1989-91 and at 5-year follow-up in 1994-97 by trained personnel. Five hundred and forty-seven women had never used HRT and 393 women used parttime or continuous HRT during follow-up of 3.8-7.9 years (mean 5.8 years). Similarly, of the 172 weight losers, 97 had never used HRT while 75 used it during follow-up. According to multiple regression analysis on the total study population (n = 940), HRT use, years since menopause and weight increase significantly predicted lower annual bone loss at both the lumbar spine and femoral neck (p < 0.005). Low baseline weight and higher age predicted higher bone loss only at the lumbar spine (p < 0.001) and high grip strength predicted lower bone loss only at the femoral neck (p = 0.021). In a sub-analysis on weight losers, weight loss predicted greater bone loss in HRT non-users (p < 0.05), whereas this was not observed in HRT users. These results remained similar after adjustment for age, weight, height, calcium intake, duration of menopause, baseline BMD and bone-affecting diseases/medication. In conclusion, the transition to menopause, HRT and weight change are the most important determinants of bone loss at both the lumbar spine and femoral neck. Furthermore, HRT seems to be effective in prevention of weight loss related bone loss.

Osteoporosis International, 2010

Osteoarthritis and Cartilage, 2011

in-person instruction on at-home knee exercise. The primary outcome measure was a composite score... more in-person instruction on at-home knee exercise. The primary outcome measure was a composite score on the Western Ontario McMaster University Osteoarthritis Index (WOMAC; 100 points), which assessed knee pain, function and stiffness on a per subject basis. The secondary outcome was the Knee Pain Scale (KPS) which assessed knee pain severity and frequency on a per knee basis; both were done at baseline, 5, 9 12, 26 and 52 weeks. Procedure-related opioid medication use, subject satisfaction and adverse events were also assessed. Results: Analysis was by intention to treat. No significant baseline differences existed between the groups in age, gender, pain duration, body mass index or WOMAC scores. 89 subjects (57±8.3 years old, 59 female) with moderate to severe KOA received an average of 4.3±0.7 prolotherapy injection sessions over a 17-week treatment period. All groups reported improved composite WOMAC scores compared to baseline status (p < 0.01) at 52 weeks. However, WOMAC scores for prolotherapy subjects, adjusted for gender, age and body mass index showed significantly greater improvement on WOMAC score at 52 weeks; 15.32±3.52 points for prolotherapy compared to 7.68±3.41 points for saline injection (p < 0.05) and 8.25±3.33 points for exercise (p < 0.05). The improvement by prolotherapy subjects exceeded minimal clinical important difference. KPS scores of prolotherapy subjects showed similar improvement per injected knee compared to baseline status (p < 0.001) and controls (p < 0.05). Prescribed post-procedure opioid medication resulted in rapid diminution of prolotherapy injection pain. Satisfaction with prolotherapy was high and there were no adverse events. Conclusions: Prolotherapy resulted in safe, significant, sustained improvement of pain, function and stiffness scores compared to blinded saline injections and at-home exercises in knee osteoarthritis.

The Journal of the Acoustical Society of America, 2012

Soft tissue layers overlying bones, with unknown thickness, can produce significant errors to bon... more Soft tissue layers overlying bones, with unknown thickness, can produce significant errors to bone quantitative ultrasound measurements. In this study dual frequency ultrasound (DFUS) technique, developed originally for pulse-echo measurements, is applied and evaluated in a configuration typical to clinical through-transmission measurement. A mathematical algorithm is presented for determination of soft tissue composition, i.e. amount of lean and fat tissue, and correction of typical clinical parameters such as broadband ultrasound attenuation (BUA) and speed of sound (SOS). Ultrasound soft tissue phantoms mimicking lean and fat tissues, were tested in five different configurations by varying the composition (0-100% of fat). Different configurations were built using 10mm of fat or lean and 30mm of fat or lean, and total thickness of soft tissue constructs varied from 20mm to 40mm. Using through-transmission measurements at 0.5 MHz center frequency the thickness of soft tissue layers...