Clinical implementation of musculoskeletal ultrasound in rheumatology in Austria

The aim of the study is to assess the clinical implementation of musculoskeletal ultrasound (MSUS) in rheumatology in Austria. A survey was conducted among Austrian rheumatologists and physicians of other specialties with a focus on rheumatology. The questionnaire was designed by the members of the Austrian Radiology-Rheumatology Initiative for Musculoskeletal UltraSound including the following items: demographics, access to MSUS and MSUS training, application of MSUS to support diagnosis, monitoring and treatment decisions, and obstacles for the routine performance of MSUS. Eighty-eight (21.9 %) out of the 402 surveyed physicians responded. No access to MSUS and/or inadequate training in the technique was more commonly reported by senior (>50 years; 64.3 and 67.7 %, respectively) than by younger physicians (16.7 %, p = 0.01 and 18.5 %, p < 0.001, respectively). The lowest availability of sonography was found among senior rheumatologists (25.0 %, p = 0.001 compared to the total group). MSUS is routinely used for diagnosis and/or monitoring purposes by 12.5 % of physicians and 20.5 % perform sonography in clinically unclear cases. A limited number of physicians apply the method to support treatment decisions and/or to evaluate treatment success. The most important obstacles for routine application of MSUS in rheumatology are limited access to ultrasound machines, lack of training/education in the technique, and time constraints in daily routine. Low access to high-end ultrasound devices, lack of training, and time constraints may explain the low appreciation of MSUS among Austrian physicians evaluating patients with rheumatic diseases.

Computational identification and quantification of trabecular microarchitecture classes by 3-D texture analysis-based clustering

High resolution peripheral quantitative computed tomography (HR-pQCT) permits the non-invasive assessment of cortical and trabecular bone density, geometry, and microarchitecture. Although researchers have developed various post-processing algorithms to quantify HR-pQCT image properties, few of these techniques capture image features beyond global structure-based metrics. While 3D-texture analysis is a key approach in computer vision, it has been utilized only infrequently in HR-pQCT research. Motivated by high isotropic spatial resolution and the information density provided by HR-pQCT scans, we have developed and evaluated a post-processing algorithm that quantifies microarchitecture characteristics via texture features in HR-pQCT scans. During a training phase in which clustering was applied to texture features extracted from each voxel of trabecular bone, three distinct clusters, or trabecular microarchitecture classes (TMACs) were identified. These TMACs represent trabecular bone regions with common texture characteristics. The TMACs were then used to automatically segment the voxels of new data into three regions corresponding to the trained cluster features. Regional trabecular bone texture was described by the histogram of relative trabecular bone volume covered by each cluster. We evaluated the intra-scanner and inter-scanner reproducibility by assessing the precision errors (PE), intra class correlation coefficients (ICC) and Dice coefficients (DC) of the method on 14 ultradistal radius samples scanned on two HR-pQCT systems. DC showed good reproducibility in intra-scanner set-up with a mean of 0.870±0.027 (no unit). Even in the inter-scanner set-up the ICC showed high reproducibility, ranging from 0.814 to 0.964. In a preliminary clinical test application, the TMAC histograms appear to be a good indicator, when differentiating between postmenopausal women with (n=18) and without (n=18) prevalent fragility fractures. In conclusion, we could demonstrate that 3D-texture analysis and feature clustering seems to be a promising new HR-pQCT post-processing tool with good reproducibility, even between two different scanners.

A nonlinear QCT-based finite element model validation study for the human femur tested in two configurations in vitro

PURPOSE

Femoral fracture is a common medical problem in osteoporotic individuals. Bone mineral density (BMD) is the gold standard measure to evaluate fracture risk in vivo. Quantitative computed tomography (QCT)-based homogenized voxel finite element (hvFE) models have been proved to be more accurate predictors of femoral strength than BMD by adding geometrical and material properties. The aim of this study was to evaluate the ability of hvFE models in predicting femoral stiffness, strength and failure location for a large number of pairs of human femora tested in two different loading scenarios.

METHODS

Thirty-six pairs of femora were scanned with QCT and total proximal BMD and BMC were evaluated. For each pair, one femur was positioned in one-legged stance configuration (STANCE) and the other in a sideways configuration (SIDE). Nonlinear hvFE models were generated from QCT images by reproducing the same loading configurations imposed in the experiments. For experiments and models, the structural properties (stiffness and ultimate load), the failure location and the motion of the femoral head were computed and compared.

RESULTS

In both configurations, hvFE models predicted both stiffness (R(2)=0.82 for STANCE and R(2)=0.74 for SIDE) and femoral ultimate load (R(2)=0.80 for STANCE and R(2)=0.85 for SIDE) better than BMD and BMC. Moreover, the models predicted qualitatively well the failure location (66% of cases) and the motion of the femoral head.

CONCLUSIONS

The subject specific QCT-based nonlinear hvFE model cannot only predict femoral apparent mechanical properties better than densitometric measures, but can additionally provide useful qualitative information about failure location.

The usefulness of computer-aided joint space analysis in the assessment of rheumatoid arthritis

OBJECTIVE

Computer-aided joint space analysis (CAJSA) is a newly developed technique for the measurement of radiogeometrically detectable joint space widths of the metacarpal-phalangeal (JSD-MCP) and proximal-interphalangeal articulations (JSD-PIP). The aim of this study was to verify the sensitivity and specificity of these CAJSA measurements in the assessment of established RA.

METHODS

Four hundred and fifty-eight participants (248 healthy subjects, 210 RA patients) underwent computerized semi-automated measurements of the JSD-MCP and JSD-PIP articulations (CAJSA, Radiogrammetry Kit, Version 1.3.6) based on digitally performed radiographs. The Sharp joint space narrowing score was also performed to determine RA-related joint space narrowing.

RESULTS

The significant severity-dependent reduction for JSD-MCP was -44.0% and for JSD-PIP, -25.94% between Sharp scores 0 and 3. The sensitivity and specificity of JSD-MCP (total) was 88.1% versus 77.8%, respectively (AUC = 0.920; P < 0.001). Furthermore, JSD-PIP (total) revealed a lower sensitivity and specificity with 61.4% and 88.7% (AUC = 0.878; P < 0.001).

CONCLUSION

The CAJSA method presented a reliable assessment of disease-related joint space narrowing in patients suffering from RA with excellent sensitivity and specificity. By providing quantitative data, other scoring methods could be significantly improved, and thereby the accuracy of the diagnosis and a better therapeutic evaluation could be achieved.

Automated threshold-independent cortex segmentation by 3D-texture analysis of HR-pQCT scans

The quantitative assessment of metabolic bone diseases relies on tissue properties such as bone mineral density (BMD) and bone microarchitecture. In spite of an increasing number of publications using high-resolution peripheral quantitative computed-tomography (HR-pQCT), the accurate and reproducible separation of cortical and trabecular bone remains challenging. In this paper, we present a novel, fully automated, threshold-independent technique for the segmentation of cortical and trabecular bone in HR-pQCT scans. This novel post-processing method is based on modeling appearance characteristics from manually annotated cases. In our experiments the algorithm automatically selected texture features with high differentiating power and trained a classifier to separate cortical and trabecular bone. From this mask, cortical thickness and tissue volume could be calculated with high accuracy. The overlap between the proposed threshold-independent segmentation tool (TIST) and manual contouring was 0.904±0.045 (Dice coefficient). In our experiments, TIST obtained higher overall accuracy in our measurements than other techniques.

Histopathological correlation supports the use of x-rays in the diagnosis of hand osteoarthritis

OBJECTIVE

To correlate histopathological and radiographic features of distal and proximal interphalangeal (DIP and PIP) joints in order to test whether the use of an x-ray examination would be beneficial to the classification/diagnosis process of hand osteoarthritis (OA).

METHODS

DIP and PIP joints were obtained from post mortem specimens (n=40). Plain x-rays of the DIP and PIP joints were taken and radiographic OA was determined by the Kellgren and Lawrence classification. Individual radiographic features were scored according to the method described by Altman. Joint samples were prepared for histological analysis; cartilage damage was graded according to the Mankin scoring system. Spearman's correlation was applied to examine the relationship between histological and radiographical changes. Differences between groups (bony swelling vs no bony swelling) were determined by Student t test.

RESULTS

A highly significant correlation was found between histological (Mankin score) and radiographic (Kellgren/Lawrence score) changes in the investigated DIP (r(s)=0.87, p<0.0001) and PIP (r(s)=0.79, p<0.0001) joints. A subgroup of patients (37.5% for DIP and 18.8% for PIP joints) showed advanced radiographic changes (Kellgren/Lawrence score ≥2) in joints without clinical bony swelling. Histologically, the mean Mankin scores accounted for 11±1.66 for DIP and 9.67±2.4 for PIP joints.

CONCLUSION

On the basis of histopathological changes of DIP and PIP joints, this investigation demonstrates the validity of x-ray examinations and supports the use of plain radiography in the diagnosis of hand OA and in the classification of hand OA in clinical trials.

Fibromuscular dysplasia mimicking Crohn's disease over a period of 23 years

Rare diseases with similar clinical presentation as more frequent gastrointestinal disorders might be challenging in the diagnostic and therapeutic management. In this case we report on a 47-year-old woman who was thought to suffer from Crohn's disease. Symptoms, macroscopic and histological aspects of the gastrointestinal tract, treatment response and clinical course had encouraged the wrong diagnosis over a period of 23 years. After the patient died in the context of a sudden clinical deterioration, fibromuscular dysplasia of the aorta was finally unmasked by post-mortem examination as underlying cause of all symptoms attributed to Crohn's disease. Re-evaluation of former diagnostic procedures revealed subtle aspects of fibromuscular dysplasia, even in biopsy samples from 23 years ago. This first case report of fibromuscular dysplasia of the aorta documents a rare pitfall in the diagnostic workup of a frequent clinical presentation in gastroenterology.

QCT-based finite element models predict human vertebral strength in vitro significantly better than simulated DEXA

SUMMARY

While dual energy X-ray absorptiometry (DXA) is considered the gold standard to evaluate fracture risk in vivo, in the present study, the quantitative computed tomography (QCT)-based finite element modeling has been found to provide a quantitative and significantly improved prediction of vertebral strength in vitro. This technique might be used in vivo considering however the much larger doses of radiation needed for QCT.

INTRODUCTION

Vertebral fracture is a common medical problem in osteoporotic individuals. Bone mineral density (BMD) is the gold standard measure to evaluate fracture risk in vivo. QCT-based finite element (FE) modeling is an engineering method to predict vertebral strength. The aim of this study was to compare the ability of FE and clinical diagnostic tools to predict vertebral strength in vitro using an improved testing protocol.

METHODS

Thirty-seven vertebral sections were scanned with QCT and high resolution peripheral QCT (HR-pQCT). Bone mineral content (BMC), total BMD (tBMD), areal BMD from lateral (aBMD-lat), and anterior-posterior (aBMD-ap) projections were evaluated for both resolutions. Wedge-shaped fractures were then induced in each specimen with a novel testing setup. Nonlinear homogenized FE models (hFE) and linear micro-FE (μFE) were generated from QCT and HR-pQCT images, respectively. For experiments and models, both structural properties (stiffness, ultimate load) and material properties (apparent modulus and strength) were computed and compared.

RESULTS

Both hFE and μFE models predicted material properties better than structural ones and predicted strength significantly better than aBMD computed from QCT and HR-pQCT (hFE: R² = 0.79, μFE: R² = 0.88, aBMD-ap: R² = 0.48-0.47, aBMD-lat: R² = 0.41-0.43). Moreover, the hFE provided reasonable quantitative estimations of the experimental mechanical properties without fitting the model parameters.

CONCLUSIONS

The QCT-based hFE method provides a quantitative and significantly improved prediction of vertebral strength in vitro when compared to simulated DXA. This superior predictive power needs to be verified for loading conditions that simulate even more the in vivo case for human vertebrae.

[Consensus diagnosis and therapy of soft tissue sarcoma]

Soft tissue sarcomas are heterogeneous tumours and relatively uncommon. There have been advances over the past years concerning pathology, clinical behaviour, diagnosis strategies and the treatment. To summarize these advances as well as making it public is one of the goals of the following consensus guidelines. But why do we need special guidelines for Austria? There are international guidelines published by the European Society of Medical Oncology (ESMO) and the National Comprehensive Cancer Network (NCCN). The cause is that we need an explanation of the matrix the ESMO and the NCCN gave according to our clinical practice, the local requirements and facilities in Austria. The following recommendations were drawn up following a consensus meeting of sarcoma specialists from the three high volume centres located at the medical universities in Austria. All fields of involved physicians from diagnosis to therapy worked together to know that soft tissue sarcomas are an interdisciplinary challenge and multimodal treatment is essential. For this reason, these guidelines not only explain but also give the state of the art and clear recommendations. One of the most important guidelines is that any patient with a suspected soft tissue sarcoma should be referred to one of the three university centres and managed by a specialist sarcoma multidisciplinary team. We hope that the consensus is helpful for the clinical practice and improves the quality of care for patients with soft tissue sarcomas in Austria.

Bone microarchitecture in hemodialysis patients assessed by HR-pQCT

BACKGROUND AND OBJECTIVES

Dialysis patients are at high risk for low-trauma bone fracture. Bone density measurements using dual-energy x-ray absorptiometry (DXA) do not reliably differentiate between patients with and without fractures. The aim of this study was to identify differences in bone microarchitecture between patients with and without a history of fracture using high-resolution peripheral quantitative computed tomography (HR-pQCT).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Seventy-four prevalent hemodialysis patients were recruited for measurements of areal bone mineral density (aBMD) by DXA and bone microarchitecture by HR-pQCT. Patients with a history of trauma-related fracture were excluded. Forty healthy volunteers served as controls. Blood levels of parathyroid hormone, vitamin D, and markers of bone turnover were determined.

RESULTS

Dialysis patients, particularly women, had markedly impaired bone microarchitecture. Patients with fractures had significantly reduced cortical and trabecular microarchitecture compared with patients without fractures. aBMD tended to be lower in patients with fractures, but differences were statistically not significant. The strongest determinant of fracture was the HR-pQCT-measured trabecular density of the tibia, which also had the highest discriminatory power to differentiate patients according to fracture status. Radial DXA had a lower discriminatory power than trabecular density.

CONCLUSIONS

Bone microarchitecture is severely impaired in dialysis patients and even more so in patients with a history of fracture. HR-pQCT can identify dialysis patients with a history of low-trauma fracture.

Sclerostin serum levels correlate positively with bone mineral density and microarchitecture in haemodialysis patients

BACKGROUND

Sclerostin is a soluble inhibitor of osteoblast function. Sclerostin is downregulated by the parathyroid hormone (PTH). Here, it was investigated whether sclerostin levels are influenced by intact (i) PTH and whether sclerostin is associated with bone turnover, microarchitecture and mass in dialysis patients.

METHODS

Seventy-six haemodialysis patients and 45 healthy controls were included in this cross-sectional study. Sclerostin, Dickkopf-1 (DKK-1), intact parathyroid hormone (iPTH), vitamin D and markers of bone turnover were analysed. A subset of 37 dialysis patients had measurements of bone mineral density (BMD) using dual-energy X-ray absorptiometry and bone microarchitecture using high-resolution peripheral quantitative computed tomography.

RESULTS

Dialysis patients had significantly higher sclerostin levels than controls (1257 pg/mL versus 415 pg/mL, P < 0.001). Significant correlations were found between sclerostin and gender (R = 0.41), iPTH (R = -0.28), 25-hydroxy-cholecalciferol (R = 0.27) and calcium (R = 0.25). Gender and iPTH remained significantly associated with sclerostin in a multivariate analysis. Sclerostin serum levels were positively associated with BMD at the lumbar spine (R = 0.46), femoral neck (R = 0.36) and distal radius (R = 0.42) and correlated positively mainly with trabecular structures such as trabecular density and number at the radius and tibia in dialysis patients. DKK-1 was related neither to bone measures nor to serologic parameters.

CONCLUSIONS

Considering that sclerostin is an inhibitor of bone formation, the observed positive correlations of serum sclerostin with BMD and bone volume were unexpected. Whether its increase in dialysis patients has direct pathogenetic relevance or is only a secondary phenomenon remains to be seen.

Validation for 2D/3D registration. I: A new gold standard data set

PURPOSE

In this article, the authors propose a new gold standard data set for the validation of two-dimensional/three-dimensional (2D/3D) and 3D/3D image registration algorithms.

METHODS

A gold standard data set was produced using a fresh cadaver pig head with attached fiducial markers. The authors used several imaging modalities common in diagnostic imaging or radiotherapy, which include 64-slice computed tomography (CT), magnetic resonance imaging using T1, T2, and proton density sequences, and cone beam CT imaging data. Radiographic data were acquired using kilovoltage and megavoltage imaging techniques. The image information reflects both anatomy and reliable fiducial marker information and improves over existing data sets by the level of anatomical detail, image data quality, and soft-tissue content. The markers on the 3D and 2D image data were segmented using ANALYZE 10.0 (AnalyzeDirect, Inc., Kansas City, KN) and an in-house software.

RESULTS

The projection distance errors and the expected target registration errors over all the image data sets were found to be less than 2.71 and 1.88 mm, respectively.

CONCLUSIONS

The gold standard data set, obtained with state-of-the-art imaging technology, has the potential to improve the validation of 2D/3D and 3D/3D registration algorithms for image guided therapy.

Effects of neuromuscular electrical stimulation on muscle layer thickness of knee extensor muscles in intensive care unit patients: a pilot study

OBJECTIVE

It is known that patients in the intensive care unit show an enormous loss of muscle mass. Neuromuscular electrical stimulation is effective in enhancing strength and endurance in immobilized patients. The aim of this study was to evaluate the effects of neuromuscular electrical stimulation on muscle layer thickness of knee extensor muscles in intensive care unit patients.

DESIGN

Randomized, controlled, double-blind, pilot trial.

PATIENTS

Thirty-three patients, male to female ratio 26:7, mean age 55 years (standard deviation 15).

METHODS

After enrolment in the study, intensive care unit patients (main diagnoses: polytrauma, cardiovascular diseases, transplantation, pneumonia, cancer) were stratified (based on the length of their stay in hospital) into 2 groups: 17 acute patients (< 7 days) and 16 long-term patients (> 14 days). Both groups were randomized to a stimulation group or a sham-stimulation group. Neuromuscular electrical stimulation was applied to knee extensor muscles for a period of 4 weeks (session time 30-60 minutes, 5 days/week). Ultrasound measurements were performed before and after the stimulation period to quantify muscle layer thickness of knee extensor muscles.

RESULTS

Only stimulated long-term patients (+4.9%) showed a significant (p = 0.013) increase in muscle layer thickness compared with sham-stimulated patients (-3.2%).

CONCLUSION

Neuromuscular electrical stimulation appears to be a useful adjunct to revert muscle wasting in intensive care unit long-term patients; however, larger studies with a larger sample size are needed to confirm these promising, but preliminary, results.

The in vivo effects of unloading and compression on T1-Gd (dGEMRIC) relaxation times in healthy articular knee cartilage at 3.0 Tesla

PURPOSE

The purpose was to investigate the in vivo effects of unloading and compression on T1-Gd relaxation times in healthy articular knee cartilage.

MATERIALS AND METHODS

Ten volunteers were enrolled, and dGEMRIC images of their right knee joints were obtained using 3.0-T MR at three timepoints: directly following exercise ("baseline"), approximately 15 min after unloading ("unloading") and during application of a compressive force (50% of the body weight) generated by a loading device via a footplate ("compression").

RESULTS

Our analysis of variance of pooled data from all cartilage zones demonstrated a significant mean T1-Gd decrease of 56.6 ms between baseline and compression (p < 0.001), and a significant mean decrease of 42.1 ms between unloading and compression (p < 0.001). No significant difference was found between baseline and unloading. Higher mean T1-Gd values were observed in the cartilage contact zone (central femoral and tibial zones; 698.3 +/- 162.2 ms) than in the non-contact zone (anterior and posterior femoral and tibial zones, and dorsal femoral zone; 662.9 +/- 149.3 ms; p < 0.01).

CONCLUSION

T1-Gd times appear to be sensitive to mechanical cartilage stress, and thus, further studies are warranted that investigate the relationship between the biochemical load response and the biomechanical properties of articular cartilage.

Computational radiology in skeletal radiography

Recent years have brought rapid developments in computational image analysis in musculo-skeletal radiology. Meanwhile the algorithms have reached a maturity that makes initial clinical use feasible. Applications range from joint space measurement to erosion quantification, and from fracture detection to the assessment of alignment angles. Current results of computational image analysis in radiography are very promising, but some fundamental issues remain to be clarified, among which the definition of the optimal trade off between automatization and operator-dependency, the integration of these tools into clinical work flow and last not least the proof of incremental clinical benefit of these methods.

[Radiological normal anatomy of the larynx and pharynx and imaging techniques]

The larynx and the pharynx represent anatomically as well as functionally a very complex organ which serves as an airway and a nutrition channel. Knowledge of anatomy and anatomical topography is therefore a fundamental basis for the evaluation of any pathological process. Beside the clinical examination and endoscopy performed by ear, nose and throat specialists, imaging techniques play a crucial role in pre-therapeutic and post-therapeutic diagnostics. The radiologist employs a conventional x-ray swallow examination, as well as contrast-enhanced multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), positron emission tomography (PET) and positron emission tomography-computed tomography (PET-CT), depending on the medical problem in question. The following article demonstrates the functional and especially the structural anatomy of the larynx and the pharynx. Furthermore, the broad range of imaging techniques in clinical use is discussed.

VITA-D: cholecalciferol substitution in vitamin D deficient kidney transplant recipients: a randomized, placebo-controlled study to evaluate the post-transplant outcome

Background

Vitamin D does not only regulate calcium homeostasis but also plays an important role as an immune modulator. It influences the immune system through the induction of immune shifts and regulatory cells resulting in immunologic tolerance. As such, vitamin D is thought to exert beneficial effects within the transplant setting, especially in kidney transplant recipients, considering the high prevalence of vitamin D deficiency in kidney transplant recipients.

Methods/Design

The VITA-D study, a randomized, placebo-controlled, double-blind study with two parallel groups including a total of 200 kidney transplant recipients, is designed to investigate the immunomodulatory and renoprotective effects of cholecalciferol (vitamin D₃) within the transplant setting. Kidney transplant recipients found to have vitamin D deficiency defined as 25-hydroxyvitamin D₃ < 50 nmol per liter will be randomly assigned to receive either oral cholecalciferol therapy or placebo and will be followed for one year. Cholecalciferol will be administered at a dose of 6800 International Units daily over a time period of one year.

The objective is to evaluate the influence of vitamin D₃ substitution in vitamin D deficient kidney transplant recipients on the post-transplant outcome. As a primary endpoint glomerular filtration rate calculated with the MDRD formula (modification of diet in renal disease) one year after kidney transplantation will be evaluated. Incidence of acute rejection episodes, and the number and severity of infections (analyzed by means of C-reactive protein) within the first year after transplantation will be monitored as well. As a secondary endpoint the influence of vitamin D₃ on bone mineral density within the first year post-transplant will be assessed. Three DXA analyses will be performed, one within the first four weeks post-transplant, one five months and one twelve months after kidney transplantation.

Trial Registration

ClinicalTrials.gov NCT00752401

Automatic quantification of joint space narrowing and erosions in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic disease that affects and potentially destroys the joints of the appendicular skeleton. The precise and reproducible quantification of the progression of joint space narrowing and the erosive bone destructions caused by RA is crucial during treatment and in imaging biomarkers in clinical trials. Current manual scoring methods exhibit high interreader variability, even after intensive training, and thus, impede the efficient monitoring of the disease. We propose a fully automatic quantitative assessment of the radiographic changes that result from RA, to increase the accuracy, reproducibility, and speed of image interpretation. Initial joint location estimates are obtained by local linear mappings based on texture features. Bone contours are delineated by active shape models comprised of statistical models of bone shape and local texture. These models are refined by snakes which increase the accuracy and allow for a fitting of pathological deviations from the training population. The method then measures joint space widths and detects erosions on the bone contour. Joint space widths are measured with a coefficient of variation of 2%-7% for repeated measurements and erosion detection exhibits an area under the receiver operating characteristic (ROC) curve of 0.89. Model landmarks serve as a reference system along the contour. These landmarks enable the definition of joint regions and more specific follow-up monitoring. The automatic quantification allows for a remote analysis, relevant for multicenter clinical trials, and reduces the workload of clinical experts since parts of the process can be managed by nonexpert personnel.

A rare reason for the end of a career in competitive tennis

Stress fractures are reported in adolescents taking part in high standard sports and they are associated with specific sites for stress fractures. The first rib is also affected in rowers and ball throwing sports. This report describes the complications of such a case in a competitive tennis player at international level practicing 5 times a week with far-reaching consequences. Due to constant load dependent pain in the region of the right shoulder, standard diagnosis, X-ray, magnetic resonance imaging (MRI) and a computed tomography (CT) scan with 3-D reconstruction were done, showing a pseudoarthrosis of the first rib. Therefore, further treatment was conservative without pain relieve. At follow-up 5 years after onset of symptoms the patient did not play tennis, he did not complain pain, but control imaging still showed a pseudoarthrosis of the first rib. Our case shows that it is important, when treating shoulder pain in the overhead athlete, to think of the possibility of a stress fracture.

[Referral guidelines in diagnostic imaging]

This article describes the causes and motivations for the introduction of referral guidelines for diagnostic radiology. Guidelines are not intended to serve as directives, but as a concept for good practice and as a basis for discussion and communication between prescribers and practitioners of radiological examinations. Although not all questions about the most effective way of implementation have been solved, it has been shown that referral guidelines serve as a means of avoiding unnecessary x-ray examinations and therefore represent an important tool within a comprehensive concept of radiation protection.

[Diagnostic imaging in pregraduate integrated curricula]

Pregraduate medical curricula are currently undergoing a reform process that is moving away from a traditional discipline-related structure and towards problem-based integrated forms of teaching. Imaging sciences, with their inherently technical advances, are specifically influenced by the effects of paradigm shifts in medical education. The teaching of diagnostic radiology should be based on the definition of three core competencies: in vivo visualization of normal and abnormal morphology and function, diagnostic reasoning, and interventional treatment. On the basis of these goals, adequate teaching methods and e-learning tools should be implemented by focusing on case-based teaching. Teaching materials used in the fields of normal anatomy, pathology, and clinical diagnosis may help diagnostic radiology to play a central role in modern pregraduate curricula.

Model-based erosion spotting and visualization in rheumatoid arthritis

RATIONALE AND OBJECTIVES

A method for the automatic detection and the visualization of erosions caused by rheumatoid arthritis is investigated. Erosion-enhanced viewing is a contribution to the computer-aided diagnosis of rheumatoid arthritis. It supports the clinician by providing the automatic marking of erosions and the visualization of any deviations from intact anatomy for a concise reviewing interface.

MATERIALS AND METHODS

A generative appearance model is used to capture the variability of intact bone and erosions. The algorithm marks erosions on hand radiographs using this model, and visualizes these erosions with the help of the residual appearance error after fitting the model built from intact bone texture. The algorithm was evaluated on 17 hand radiographs. The standard of reference was an annotation of the erosions by a musculoskeletal radiologist.

RESULTS

Detection results from the algorithm are reported for a set of 17 radiographs of moderately diseased hands. With a specificity of 84%, the detection of unequivocal erosions achieved a sensitivity of 85%. A receiver operating characteristic analysis yields an area under the curve of 0.92. The visualization provided a clear representation of the erosions as determined by two musculoskeletal radiologists.

CONCLUSION

The automatic spotting of erosions provides promising results, and the visualization of the deviation from healthy anatomy aids clinicians in the evaluation of the erosions and in the reviewing of automatic detection results.

Research in hand osteoarthritis: time for reappraisal and demand for new strategies. An opinion paper

BACKGROUND

Osteoarthritis of the hands is a prevalent musculoskeletal disease with a considerable effect on patients' lives, but knowledge and research results in the field of hand osteoarthritis are limited. Therefore, the Disease Characteristics in Hand OA (DICHOA) initiative was founded in early 2005 with the aim of addressing key issues and facilitating research into hand osteoarthritis.

OBJECTIVE

To review and discuss current knowledge on hand osteoarthritis with regard to aetiopathogenesis, diagnostic criteria, biomarkers and clinical outcome measures.

METHODS

Recommendations were made based on a literature review.

RESULTS

Outcomes of hand osteoarthritis should be explored, including patient perspective on the separate components of disease activity, damage and functioning. All imaging techniques should be cross-validated for hand osteoarthritis with clinical status, including disease activity, function and performance, biomarkers and long-term outcome. New imaging modalities are available and need scoring systems and validation. The role of biomarkers in hand osteoarthritis has to be defined.

CONCLUSION

Future research in hand osteoarthritis is warranted.

[Overuse syndromes of the foot]

Overuse syndromes due to lifestyle problems or sporting activities commonly lead to foot abnormalities. The tendons of the long flexor and extensor muscles are specifically prone to degeneration. The various disorders may be classified by a grading system that includes peritendinous inflammation, degenerative tendon disease, and ruptures. Bone marrow edema is another typical manifestation of overuse. It may be differentiated from inflammatory or traumatic forms of edema by its anatomic distribution. Systematic pattern recognition is based on the concept of musculotendinous and osseous kinetic chains.

Impact of sonography in gouty arthritis: Comparison with conventional radiography, clinical examination, and laboratory findings

OBJECTIVE

To explore the typical sonographic features of gray-scale and Power Doppler of acute and chronic gouty arthritis in conjunction with radiographic, clinical, and laboratory findings.

MATERIALS AND METHODS

All hand, finger, and toe joints of 19 patients with acute and chronic gout were examined with gray-scale and Power Doppler sonography. The number and size of bone changes detected with sonography was compared to radiographic findings. Vascularization of the synovial tissue was scored on Power Doppler (grades 0-3), and was compared with clinical appearance, including swelling, tenderness, and redness (grades 0-3).

RESULTS

In acute gout, mild to moderate echogenic periarticular nodules with sonotransmission and hypervascularization of the edematous surrounding soft tissue were found. In chronic gout, tophaceous nodules completely blocked transmission of US wave, leading to strong reflexion and dorsal shadowing in a minority of cases. No significant difference in the detection of large bone changes (>2mm) was found between sonography and radiography. However, gray-scale sonography was significantly more sensitive in the detection of small bone changes (p<0.001). Power Doppler scores were statistically significantly higher than clinical examination scores (p<0.001).

DISCUSSION

Sonography is superior to radiographs in evaluating small bone changes. The inflammatory process in joints can be better detected with Power Doppler sonography than with clinical examination. Typical sonographic appearance of acute and in particular of chronic gout might provide clues on gouty arthritis that adds to the information available from conventional radiography, clinical, and laboratory findings.

Comparison of laser surface scanning and fiducial marker–based registration in frameless stereotaxy

✓The authors compared the accuracy of laser surface scanning patient registration using the commercially available Fazer (Medtronic, Inc.) with the conventional registration procedure based on fiducial markers (FMs) in computer-assisted surgery.

Four anatomical head specimens were prepared with 10 titanium microscrews placed at defined locations and scanned with a 16-slice spiral computed tomography unit. To compare the two registration methods, each method was applied five times for each cadaveric specimen; thus data were obtained from 40 registrations. Five microscrews (selected following a randomization protocol) were used for each FM-based registration; the other five FMs were selected for coordinate measurements by touching with a point measurement stylus. Coordinates of these points were also measured manually on the screen of the navigation computer. Coordinates were measured in the same manner after laser surface registration.

The root mean square error as calculated by the navigation system ranged from 1.3 to 3.2 mm (mean 1.8 mm) with the Fazer and from 0.3 to 1.8 mm (mean 1.0 mm) with FM-based registration. The overall mean deviations (the arithmetic mean of the mean deviations of measurements on the four specimens) were 3.0 mm (standard deviation [SD] range 1.4–2.6 mm) with the Fazer and 1.4 mm (SD range 0.4–0.9 mm) with the FMs. The Fazer registration scans 300 surface points. Statistical tests showed the difference in the accuracy of these methods to be highly significant.

In accordance with the findings of other groups, the authors concluded that the inclusion of a larger number of registration points might improve the accuracy of Fazer registration.

Power Doppler sonography and pulse-inversion harmonic imaging in evaluation of rheumatoid arthritis synovitis

OBJECTIVE

This study evaluates the value of contrast-enhanced pulse-inversion harmonic imaging (PIHI) to detect synovial vascularization and thus the therapeutic effects of prednisolone treatment on the inflammation in finger joints in rheumatoid arthritis (RA).

MATERIALS AND METHODS

Before and after 7 days of mid- to high-dose steroid therapy, blood tests and clinical and sonographic examinations were assessed in 14 patients. Two hundred eighty finger joints (metacarpophalangeal [MCP] I-V, interphalangeal [IP], and proximal interphalangeal [PIP] II-V) were investigated on power Doppler sonography to determine, in each patient, the finger joint with the strongest hypervascularization and to score the synovial vascularization. Further dynamic examination of the selected joint was performed on PIHI after i.v. administration of a second-generation sonographic contrast medium. Vascularization was quantified by calculating the area under the time-intensity curves. The changes in signal intensities before and after therapy were correlated with clinical examinations (disease activity score [DAS]).

RESULTS

The score of the joint with the strongest hypervascularization assessed by power Doppler sonography decreased significantly from 1.7 to 1.3 (p < 0.01); however, in six patients, no change was assessed after steroid therapy. In all patients, a significant reduction in PIHI signals was observed after therapy (p < 0.05). The baseline and follow-up median values of the area under the time-intensity curves were 8.56 +/- 1.28 and 7.65 +/- 0.66, respectively. The median values of the DAS decreased significantly from 4.90 +/- 0.86 to 3.6 +/- 1.0 (p < 0.01) 7 days after the steroid therapy.

CONCLUSION

PIHI and power Doppler sonography enable the detection of synovial perfusion alterations after steroid therapy and, therefore, may be useful tools for the evaluation of active inflammation in RA and for the assessment of therapeutic response. However, minor changes of synovial vascularization can be better detected on PIHI than on power Doppler sonography.

Bone erosions and bone marrow edema as defined by magnetic resonance imaging reflect true bone marrow inflammation in rheumatoid arthritis

OBJECTIVE

To investigate the pathologic nature of features termed "bone erosion" and "bone marrow edema" (also called "osteitis) on magnetic resonance imaging (MRI) scans of joints affected by rheumatoid arthritis (RA).

METHODS

RA patients scheduled for joint replacement surgery (metacarpophalangeal or proximal interphalangeal joints) underwent MRI on the day before surgery. The presence and localization of bone erosions and bone marrow edema as evidenced by MRI (MRI bone erosions and MRI bone marrow edema) were documented in each joint (n=12 joints). After surgery, sequential sections from throughout the whole joint were analyzed histologically for bone marrow changes, and these results were correlated with the MRI findings.

RESULTS

MRI bone erosion was recorded based on bone marrow inflammation adjacent to a site of cortical bone penetration. Inflammation was recorded based on either invading synovial tissue (pannus), formation of lymphocytic aggregates, or increased vascularity. Fat-rich bone marrow was replaced by inflammatory tissue, increasing water content, which appears as bright signal enhancement on STIR MRI sequences. MRI bone marrow edema was recorded based on the finding of inflammatory infiltrates, which were less dense than those of MRI bone erosions and localized more centrally in the joint. These lesions were either isolated or found in contact with MRI bone erosions.

CONCLUSION

MRI bone erosions and MRI bone marrow edema are due to the formation of inflammatory infiltrates in the bone marrow of patients with RA. This emphasizes the value of MRI in sensitively detecting inflammatory tissue in the bone marrow and demonstrates that the inflammatory process extends to the bone marrow cavity, which is an additional target structure for antiinflammatory therapy.

[Computer assisted radiological diagnostics of arthritic joint alterations]

Computer assisted diagnosis (CAD) schemes are currently used in the field of musculoskeletal diseases to quantitatively assess vertebral fractures, joint space narrowing, andr erosion. Most systems work semi-automatically, i.e. they are operator dependent in the selection of anatomical landmarks. Fully automatic programs are currently under development. Some CAD products have already been successfully used in clinical trials.