T2*-Mapping of Knee Cartilage in Response to Mechanical Loading in Alpine Skiing: A Feasibility Study.

PURPOSE: This study intends to establish a study protocol for the quantitative magnetic resonance imaging (qMRI) measurement of biochemical changes in knee cartilage induced by mechanical stress during alpine skiing with the implementation of new spring-loaded ski binding. METHODS: The MRI-knee-scans (T2*-mapping) of four skiers using a conventional and a spring-loaded ski binding system, alternately, were acquired before and after 1 h/4 h of exposure to alpine skiing. Intrachondral T2* analysis on 60 defined regions of interest in the femorotibial knee joint (FTJ) was conducted. Intra- and interobserver variability and relative changes in the cartilage T2* signal and thickness were calculated. RESULTS: A relevant decrease in the T2* time after 4 h of alpine skiing could be detected at the majority of measurement times. After overnight recovery, the T2* time increased above baseline. Although, the total T2* signal in the superficial cartilage layers was higher than that in the lower ones, no differences between the layers in the T2* changes could be detected. The central and posterior cartilage zones of the FTJ responded with a stronger T2* alteration than the anterior zones. CONCLUSIONS: For the first time, a quantitative MRI study setting could be established to detect early knee cartilage reaction due to alpine skiing. Relevant changes in the T2* time and thus in the intrachondral collagen microstructure and the free water content were observed.

[Therapeutic injections and manual medicine in low-back pain : Bimodal synergies between evidence and empiricism]. / Therapeutische Injektion und Manuelle Medizin beim tiefen Rückenschmerz : Bimodale Synergien zwischen Evidenz und Empirie.

BACKGROUND: Oriented towards the therapy planning and management of rheumatic patients, and based on the differentiated therapeutic principles of manual medicine (MM) with knowledge on evidence of therapeutic local infiltration techniques (TLI), the author pleads for the establishment of a structured, mechanism-based therapy concept in the sense of "treat to target" (T2T) for patients with (chronic) degenerative low-back pain (LBP) in outpatient pain therapy care. DIAGNOSTICS: This requires a consistent (primary) diagnosis with pain analysis under the premise that LBP is always specific if it is structurally and functionally conditioned. A broad bio-psycho-social anamnesis and structure-based clinical diagnosis (imaging) with functional differentiation according to MM principles and, if necessary, interventional blocks, should result in the expression of a three-level diagnosis as a prerequisite for a mechanism-based, hierarchic step therapy in LBP. In this article, this is presented in a pragmatic, case-oriented manner, with the implementation of techniques and evidence of TLI and MM.

Cardiac structure and function in response to a multi-stage marathon over 4486 km.

AIMS: To investigate whether participation in the Trans Europe Foot Race 2009 (TEFR), an ultramarathon race held over 64 consecutive days and 4486 km, led to changes in cardiac structure and function. METHODS: Cardiac magnetic resonance imaging was performed in 20 of 67 participating runners (two women; mean ± SD age 47.8 ± 10.4 years) at three time points (baseline scan at 294 ± 135 km (B), scan two at 1735 ± 86 km (T1) and scan three at 3370 ± 90 km (T2)) during the TEFR. Imaging included an assessment of left ventricular structure (mass) and function (strain). In parallel, cardiac troponin I, NT-pro-BNP, myostatin and GDF11 were determined in venous blood samples. A subsample of ten runners returned for a follow-up scan eight months after the race. RESULTS: Left ventricular mass increased significantly (B, 158.5 ± 23.8 g; T1, 165.1 ± 23.2 g; T2, 167 ± 24.6 g; p < 0.001) over the course of the race, although no significant change was seen in the remaining structural and functional parameters. Serum concentrations of cardiac troponin I and NT-proBNP significantly increased 1.5 - and 3.5-fold, respectively, during the first measurement interval, with no further increase thereafter (cardiac troponin I, 6.8 ± 3.1 (B), 16.9 ± 10.4 (T1) and 17.1 ± 9.7 (T2); NT-proBNP, 30.3 ± 22.8 (B), 135.9 ± 177.5 (T1) and 111.2 ± 87.3 (T2)), whereas the growth markers myostatin and GDF11 did not change. No association was observed with functional parameters, including the ejection fraction and the volume of both ventricles. The follow-up scans showed a reduction to baseline values (left ventricular mass 157 ± 19.3 g). CONCLUSIONS: High exercise-induced cardiac volume load for >2 months in ultra-endurance runners results in a physiological structural adaptation with no sign of adverse cardiovascular remodelling.

Long distance running - Can bioprofiling predict success in endurance athletes?

The TransEuropeFootRace (TEFR) was one of the most extreme multistage competitions worldwide. The ultramarathon took the runners over a distance of 4487 km, from Bari, Italy, to the North Cape, Norway, in 64 days. The participating ultra-long-distance runners had to complete almost two marathons per day (~70 km). The race was accompanied by a research team analysing adaptations of different organ systems of the human body that were exposed to a chronic lack of regeneration time. Here, we analyzed runner's urine using mass spectrometric profiling of thousands of low-molecular weight compounds. The results indicated that pre-race molecular factors can predict finishers and separate them from nonfinishers already before the race. These observations were related to the training volume as finishers ran about twice as many kilometers per week before TEFR than nonfinishers, thus apparently achieving a higher performance level and resistance against overuse. While this hypothesis needs to be validated in future long-distance races, the bioprofiling experiments suggest that the competition readiness of the runners is measurable and might be adjustable.

A mobile MRI field study of the biochemical cartilage reaction of the knee joint during a 4,486 km transcontinental multistage ultra-marathon using T2* mapping.

Nearly nothing is known about the consequences of ultra-long-distance running on knee cartilage. In this mobile MRI field study, we analysed the biochemical effects of a 4,486 km transcontinental multistage ultra-marathon on femorotibial joint (FTJ) cartilage. Serial MRI data were acquired from 22 subjects (20 male, 18 finisher) using a 1.5 T MR scanner mounted on a 38-ton trailer, travelling with the participants of the TransEurope FootRace (TEFR) day by day over 64 stages. The statistical analyses focused on intrachondral T2* behaviour during the course of the TEFR as the main outcome variable of interest. T2* mapping (sagittal FLASH T2* weighted gradient echo) is a validated and highly accurate method for quantitative compositional cartilage analysis of specific weightbearing areas of the FTJ. T2* mapping is sensitive to changes in the equilibrium of free intrachondral water, which depends on the content and orientation of collagen and the proteoglycan content in the extracellular cartilage matrix. Within the first 1,100 km, a significant running load-induced T2* increase occurred in all joint regions: 44.0% femoral-lateral, 42.9% tibial-lateral, 34.9% femoral-medial, and 25.1% tibial-medial. Osteochondral lesions showed no relevant changes or new occurrence during the TEFR. The reasons for stopping the race were not associated with knee problems. As no further T2* elevation was found in the second half of the TEFR but a decreasing T2* trend (recovery) was observed after the 3,500 km run, we assume that no further softening of the cartilage occurs with ongoing running burden over ultra-long distances extending 4,500 km. Instead, we assume the ability of the FTJ cartilage matrix to reorganize and adapt to the load.

Femoropatellar Joint Reaction Detected During a 4486 KM Ultramarathon with Mobile MRI.

Almost nothing is known about the condition of the knee joints of multistage ultra-marathon (MSUM) runner. This is first image-based investigation of the femoropatellar joint (FPJ) using a mobile 1.5T MRI accompanying the MSUM TransEurope Foot-Race (TEFR) 64 stages over 4486 km. Twenty-two (20 male) subjects got a knee MRI-protocol at defined measurement intervals during TEFR: T2*-mapping (FLASH T2*-GRE), TIRM, and fat saturated PD -sequence. In the FPJ 12 different regions were evaluated regarding cartilage T2* and thickness changes and cartilage lesions in course of TEFR and a test on possible compounding factors (running burden, BMI, age) was done if being appropriate. No significant changes in cartilage thickness- and T2*-values were found during TEFR. In 8 runners, at least one single cartilage lesion (Grade 2-3) was found at baseline, but no significant race-related adjacent T2*-changes or progress of the defects could be detected. Analyses on compounding factors were negative. In knees with MPP (5) significantly lower adjacent T2*-values were found. The extreme running burden of a MSUM seems not to have a relevant negative influence on the FPJ tissues, even if cartilage lesions are present.

Pre-race determinants influencing performance and finishing of a transcontinental 4486-km ultramarathon.

BACKGROUND: Pre-race determinants influencing performance and finishing of one of the largest transcontinental multistage ultramarathons were investigated. METHODS: Forty-four participants of the TransEurope FootRace 2009 (TEFR), running 4486 km in 64 stages (average 70.1 km daily) were analyzed regarding training and running history. This included years of regular endurance running (PRY), number of finished marathons, ultramarathons (UM) and multistage ultramarathons (MSUM), pre-race records (PRR) for marathon and specific UM races and the extent of pre-race training (PRT) in the last year before TEFR: volume (km/week), duration (h/week) and intensity (km/h). RESULTS: Mean total running speed during TEFR was 8.25 km/h.Seventy-one percent of subjects finished the race. The mean PRT-volume extends 5500 km. Finishers and non-finishers of the TEFR did not show significant difference in any tested pre-race determinants. There was no association between PRY, number of finished marathons, UM, and MSUM and TEFR performance. There was very strong positive correlation between PRT-intensity and TEFR performance. PRT volume correlated with a medium effect size to TEFR performance. PRR in specific ultra-races (6-hour, 50-km, 100-km races) showed a high correlation to TEFR performance. Performance in ultramarathon correlates inversely with age. CONCLUSIONS: Like in other endurance disciplines with shorter distances, in ultra-long multistage endurance running the athletes also need a stage-specific pre-race experience, training and adaptation if he wants to end up with a good performance. But dropping out of a MSUM seems not to be consistent with regard to specific pre-race experience. Further research results of TEFR project may reveal potential risk factors for non-finishing a transcontinental footrace.

[Modern radiological diagnostics in spine surgery]. / Moderne radiologische Diagnostik in der Wirbelsäulenchirurgie.

BACKGROUND: Radiological imaging is important in the preoperative diagnosis of many forms of spinal pathology and plays a fundamental role in the assessment of p.o. effects, which can be verified on the spinal column as well as on the surrounding soft tissues, depending on the imaging method used. AIM: The article provides an overview of the current status and possibilities of radiological diagnostic methods for the verification of possibly recommended spine surgery in the context of degenerative, inflammatory-infectious, post-traumatic or p.o. pathologies and changes in the spine: X­rays, computed tomography (CT), magnetic resonance imaging (MRI). The supplementary nuclear medicine procedures (scintigraphy, PET[-CT], SPECT, etc.) which may be required for special questions are not discussed. MATERIAL AND METHODS: The merits and limitations of the techniques used in the investigation of advanced degenerative spinal pathologies and post-traumatic conditions are discussed, with multidetector CT being the focus of attention in spinal clearance for traumatic injuries. In most cases of spinal infection, MRI images, as a central diagnostic tool, show typical findings such as destruction of adjacent endplates, bone marrow and intervertebral disc abnormalities, and paravertebral or epidural abscesses. However, it is not always easy to diagnose a spinal infection, especially if atypical MR patterns of infectious spondylitis are present. Knowledge of them means misdiagnosis and improper treatment can be avoided. RESULTS: It is shown that high-quality modern radiological examinations are essential for diagnosis and p.o. management, as these provide answers to the main questions in the treatment: Is the entity/injury stable or unstable, acute or old, benign or malign; is there a myelopathy or p.o. complication? DISCUSSION: The main indications for p.o. diagnostic imaging, difficulties such as metal artefact formation, and potential pitfalls are analyzed. Entity-specific radiological image patterns, imaging algorithms and differential diagnostic peculiarities are presented and discussed based on current literature and selected case studies.

MRI Cartilage Assessment of the Subtalar and Midtarsal Joints During a Transcontinental Ultramarathon - New Insights into Human Locomotion.

MR measurements can be accurately performed during 4486 km of running, opening a window into in vivo assessment of hindfoot articular cartilage under extreme ultra-endurance loading. This observational cross-sectional study included 22 randomized participants of TransEurope FootRace between Italy and the North Cape, which was accompanied by a trailer-mounted 1.5T MRI scanner over 9 weeks. Four follow up MR examinations of subtalar and midtarsal joints were performed. Statistics of cartilage T2* and thickness were obtained. Nearly all observed joints showed an initial significant mean T2* increase of 20.9% and 26.3% for the left and right side, followed by a relative decrease of 28.5% and 16.0% during the second half, respectively. It could be demonstrated that mobile MRI field studies allow in vivo functional tissue observations under extreme loading. Elevated T2* values recovered during the second half of the ultramarathon supported the evidence that this response is a physiological adaptive mechanism of chondrocyte function via upregulation of de novo synthesis of proteoglycans and collagen. These changes occurred in a distinct asymmetric pattern leaving a "biochemical signature" of articular cartilage that allows in vivo insight into joint loading. In conclusion, the normal articular cartilage of the hindfoot is resilient and adaptive, leaving extreme endurance activities up to limitless human ambition.

Changes in Cartilage Biomarker Levels During a Transcontinental Multistage Footrace Over 4486 km.

BACKGROUND: Cartilage turnover and load-induced tissue changes are frequently assessed by quantifying concentrations of cartilage biomarkers in serum. To date, information on the effects of ultramarathon running on articular cartilage is scarce. HYPOTHESIS: Serum concentrations of cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)-1, MMP-3, MMP-9, COL2-3/4C long mono (C2C), procollagen type II C-terminal propeptide (CPII), and C2C:CPII will increase throughout a multistage ultramarathon. STUDY DESIGN: Descriptive laboratory study. METHODS: Blood samples were collected from 36 runners (4 female; mean age, 49.0 ± 10.7 years; mean body mass index, 23.1 ± 2.3 kg/m2 [start] and 21.4 ± 1.9 kg/m2 [finish]) before (t0) and during (t1: 1002 km; t2: 2132 km; t3: 3234 km; t4: 4039 km) a 4486-km multistage ultramarathon. Serum COMP, MMP-1, MMP-3, MMP-9, C2C, and CPII levels were assessed using commercial enzyme-linked immunosorbent assays. Linear mixed models were used to detect significant changes in serum biomarker levels over time with the time-varying covariates of body weight, running speed, and daily running time. RESULTS: Serum concentrations of COMP, MMP-9, and MMP-3 changed significantly throughout the multistage ultramarathon. On average, concentrations increased during the first measurement interval (MI1: t1-t0) by 22.5% for COMP (95% CI, 0.29-0.71 ng/mL), 22.3% for MMP-3 (95% CI, 0.24-15.37 ng/mL), and 95.6% for MMP-9 (95% CI, 81.7-414.5 ng/mL) and remained stable throughout MI2, MI3, and MI4. Serum concentrations of MMP-1, C2C, CPII, and C2C:CPII did not change significantly throughout the multistage ultramarathon. Changes in MMP-3 were statistically associated with changes in COMP throughout the ultramarathon race (MMP-3: Wald Z = 3.476, P = .001). CONCLUSION: Elevated COMP levels indicate increased COMP turnover in response to extreme running, and the association between load-induced changes in MMP-3 and changes in COMP suggests the possibility that MMP-3 may be involved in the degradation of COMP. CLINICAL RELEVANCE: These results suggest that articular cartilage is able to adapt even to extreme physical activity, possibly explaining why the risk of degenerative joint disease is not elevated in the running population.

Moving in extreme environments: extreme loading; carriage versus distance.

This review addresses human capacity for movement in the context of extreme loading and with it the combined effects of metabolic, biomechanical and gravitational stress on the human body. This topic encompasses extreme duration, as occurs in ultra-endurance competitions (e.g. adventure racing and transcontinental races) and expeditions (e.g. polar crossings), to the more gravitationally limited load carriage (e.g. in the military context). Juxtaposed to these circumstances is the extreme metabolic and mechanical unloading associated with space travel, prolonged bedrest and sedentary lifestyle, which may be at least as problematic, and are therefore included as a reference, e.g. when considering exposure, dangers and (mal)adaptations. As per the other reviews in this series, we describe the nature of the stress and the associated consequences; illustrate relevant regulations, including why and how they are set; present the pros and cons for self versus prescribed acute and chronic exposure; describe humans' (mal)adaptations; and finally suggest future directions for practice and research. In summary, we describe adaptation patterns that are often U or J shaped and that over time minimal or no load carriage decreases the global load carrying capacity and eventually leads to severe adverse effects and manifest disease under minimal absolute but high relative loads. We advocate that further understanding of load carrying capacity and the inherent mechanisms leading to adverse effects may advantageously be studied in this perspective. With improved access to insightful and portable technologies, there are some exciting possibilities to explore these questions in this context.

Regionally accentuated reversible brain grey matter reduction in ultra marathon runners detected by voxel-based morphometry.

BACKGROUND: During the 4,487 km ultra marathon TransEurope-FootRace 2009 (TEFR09), runners showed catabolism with considerable reduction of body weight as well as reversible brain volume reduction. We hypothesized that ultra marathon athletes might have developed changes to grey matter (GM) brain morphology due to the burden of extreme physical training. Using voxel-based morphometry (VBM) we undertook a cross sectional study and two longitudinal studies. METHODS: Prior to the start of the race 13 runners volunteered to participate in this study of planned brain scans before, twice during, and 8 months after the race. A group of matched controls was recruited for comparison. Twelve runners were able to participate in the scan before the start of the race and were taken into account for comparison with control persons. Because of drop-outs during the race, VBM could be performed in 10 runners covering the first 3 time points, and in 7 runners who also had the follow-up scan after 8 months. Volumetric 3D datasets were acquired using an MPRAGE sequence. A level of p < 0.05, family-wise corrected for multiple comparisons was the a priori set statistical threshold to infer significant effects from VBM. RESULTS: Baseline comparison of TEFR09 participants and controls revealed no significant differences regarding GM brain volume. During the race however, VBM revealed GM volume decreases in regionally distributed brain regions. These included the bilateral posterior temporal and occipitoparietal cortices as well as the anterior cingulate and caudate nucleus. After eight months, GM normalized. CONCLUSION: Contrary to our hypothesis, we did not observe significant differences between TEFR09 athletes and controls at baseline. If this missing difference is not due to small sample size, extreme physical training obviously does not chronically alter GM.However, during the race GM volume decreased in brain regions normally associated with visuospatial and language tasks. The reduction of the energy intensive default mode network as a means to conserve energy during catabolism is discussed. The changes were reversible after 8 months.Despite substantial changes to brain composition during the catabolic stress of an ultra marathon, the observed differences seem to be reversible and adaptive.

Characteristics, changes and influence of body composition during a 4486 km transcontinental ultramarathon: results from the TransEurope FootRace mobile whole body MRI-project.

BACKGROUND: Almost nothing is known about the medical aspects of runners doing a transcontinental ultramarathon over several weeks. The results of differentiated measurements of changes in body composition during the Transeurope Footrace 2009 using a mobile whole body magnetic resonance (MR) imager are presented and the proposed influence of visceral and somatic adipose and lean tissue distribution on performance tested. METHODS: 22 participants were randomly selected for the repeated MR measurements (intervals: 800 km) with a 1.5 Tesla MR scanner mounted on a mobile unit during the 64-stage 4,486 km ultramarathon. A standardized and validated MRI protocol was used: T1 weighted turbo spin echo sequence, echo time 12 ms, repetition time 490 ms, slice thickness 10 mm, slice distance 10 mm (breath holding examinations). For topographic tissue segmentation and mapping a modified fuzzy c-means algorithm was used. A semi-automatic post-processing of whole body MRI data sets allows reliable analysis of the following body tissue compartments: Total body volume (TV), total somatic (TSV) and total visceral volume (TVV), total adipose (TAT) and total lean tissue (TLT), somatic (SLT) and visceral lean tissue (VLT), somatic (SAT) and visceral adipose tissue (VAT) and somatic adipose soft tissue (SAST). Specific volume changes were tested on significance. Tests on difference and relationship regarding prerace and race performance and non-finishing were done using statistical software SPSS. RESULTS: Total, somatic and visceral volumes showed a significant decrease throughout the race. Adipose tissue showed a significant decrease compared to the start at all measurement times for TAT, SAST and VAT. Lean adipose tissues decreased until the end of the race, but not significantly. The mean relative volume changes of the different tissue compartments at the last measurement compared to the start were: TV -9.5% (SE 1.5%), TSV -9.4% (SE 1.5%), TVV -10.0% (SE 1.4%), TAT -41.3% (SE 2.3%), SAST -48.7% (SE 2.8%), VAT -64.5% (SE 4.6%), intraabdominal adipose tissue (IAAT) -67.3% (SE 4.3%), mediastinal adopose tissue (MAT) -41.5% (SE 7.1%), TLT -1.2% (SE 1.0%), SLT -1.4% (SE 1.1%). Before the start and during the early phase of the Transeurope Footrace 2009, the non-finisher group had a significantly higher percentage volume of TVV, TAT, SAST and VAT compared to the finisher group. VAT correlates significantly with prerace training volume and intensity one year before the race and with 50 km- and 24 hour-race records. Neither prerace body composition nor specific tissue compartment volume changes showed a significant relationship to performance in the last two thirds of the Transeurope Footrace 2009. CONCLUSIONS: With this mobile MRI field study the complex changes in body composition during a multistage ultramarathon could be demonstrated in detail in a new and differentiated way. Participants lost more than half of their adipose tissue. Even lean tissue volume (mainly skeletal muscle tissue) decreased due to the unpreventable chronic negative energy balance during the race. VAT has the fastest and highest decrease compared to SAST and lean tissue compartments during the race. It seems to be the most sensitive morphometric parameter regarding the risk of non-finishing a transcontinental footrace and shows a direct relationship to prerace-performance. However, body volume or body mass and, therefore, fat volume has no correlation with total race performances of ultra-athletes finishing a 4,500 km multistage race.

Automated localisation and boundary identification of superficial femoral artery on MRI sequences.

In this paper, an automated method to localise the right superficial femoral artery (SFA) and identify its boundary on magnetic resonance imaging (MRI) sequences without contrast medium injection is proposed. Some anatomical knowledge combined with the mathematical morphology is used to distinguish SFA from other vessels. Afterwards, the directional gradient, continuity and the local contrast are applied as features to identify the artery's boundary using dynamic programming. The accuracy analysis shows that the system has average unsigned errors 3.1 ± 3.1% on five sequences compared to experts' manual tracings.

Substantial and reversible brain gray matter reduction but no acute brain lesions in ultramarathon runners: experience from the TransEurope-FootRace Project.

BACKGROUND: During the extremely challenging 4,487 km ultramarathon TransEurope-FootRace 2009, runners showed considerable reduction of body weight. The effects of this endurance run on brain volume changes but also possible formation of brain edema or new lesions were explored by repeated magnetic resonance imaging (MRI) studies. METHODS: A total of 15 runners signed an informed consent to participate in this study of planned brain scans before, twice during, and about 8 months after the race. Because of dropouts, global gray matter volume analysis could only be performed in ten runners covering three timepoints, and in seven runners who also had a follow-up scan. Scanning was performed on three identical 1.5 T Siemens MAGNETOM Avanto scanners, two of them located at our university. The third MRI scanner with identical sequence parameters was a mobile MRI unit escorting the runners. Volumetric 3D datasets were acquired using a magnetization prepared rapid acquisition gradient echo (MPRAGE) sequence. Additionally, diffusion-weighted (DWI) and fluid attenuated inversion recovery (FLAIR) imaging was performed. RESULTS: Average global gray matter volume as well as body weight significantly decreased by 6% during the race. After 8 months, gray matter volume returned to baseline as well as body weight. No new brain lesions were detected by DWI or FLAIR imaging. CONCLUSIONS: Physiological brain volume reduction during aging is less than 0.2% per year. Therefore a volume reduction of about 6% during the 2 months of extreme running appears to be substantial. The reconstitution in global volume measures after 8 months shows the process to be reversible. As possible mechanisms we discuss loss of protein, hypercortisolism and hyponatremia to account for both substantiality and reversibility of gray matter volume reductions. Reversible brain volume reduction during an ultramarathon suggests that extreme running might serve as a model to investigate possible mechanisms of transient brain volume changes. However, despite massive metabolic load, we found no new lesions in trained athletes participating in a multistage ultramarathon.See related commentary http://www.biomedcentral.com/1741-7015/10/171.

The TransEurope FootRace Project: longitudinal data acquisition in a cluster randomized mobile MRI observational cohort study on 44 endurance runners at a 64-stage 4,486 km transcontinental ultramarathon.

BACKGROUND: The TransEurope FootRace 2009 (TEFR09) was one of the longest transcontinental ultramarathons with an extreme endurance physical load of running nearly 4,500 km in 64 days. The aim of this study was to assess the wide spectrum of adaptive responses in humans regarding the different tissues, organs and functional systems being exposed to such chronic physical endurance load with limited time for regeneration and resulting negative energy balance. A detailed description of the TEFR project and its implemented measuring methods in relation to the hypotheses are presented. METHODS: The most important research tool was a 1.5 Tesla magnetic resonance imaging (MRI) scanner mounted on a mobile unit following the ultra runners from stage to stage each day. Forty-four study volunteers (67% of the participants) were cluster randomized into two groups for MRI measurements (22 subjects each) according to the project protocol with its different research modules: musculoskeletal system, brain and pain perception, cardiovascular system, body composition, and oxidative stress and inflammation. Complementary to the diverse daily mobile MR-measurements on different topics (muscle and joint MRI, T2*-mapping of cartilage, MR-spectroscopy of muscles, functional MRI of the brain, cardiac and vascular cine MRI, whole body MRI) other methods were also used: ice-water pain test, psychometric questionnaires, bioelectrical impedance analysis (BIA), skinfold thickness and limb circumference measurements, daily urine samples, periodic blood samples and electrocardiograms (ECG). RESULTS: Thirty volunteers (68%) reached the finish line at North Cape. The mean total race speed was 8.35 km/hour. Finishers invested 552 hours in total. The completion rate for planned MRI investigations was more than 95%: 741 MR-examinations with 2,637 MRI sequences (more than 200,000 picture data), 5,720 urine samples, 244 blood samples, 205 ECG, 1,018 BIA, 539 anthropological measurements and 150 psychological questionnaires. CONCLUSIONS: This study demonstrates the feasibility of conducting a trial based centrally on mobile MR-measurements which were performed during ten weeks while crossing an entire continent. This article is the reference for contemporary result reports on the different scientific topics of the TEFR project, which may reveal additional new knowledge on the physiological and pathological processes of the functional systems on the organ, cellular and sub-cellular level at the limits of stress and strain of the human body. Please see related articles: http://www.biomedcentral.com/1741-7015/10/76 and http://www.biomedcentral.com/1741-7015/10/77.

Diagnostic value of lumbar facet joint injection: a prospective triple cross-over study.

The diagnosis "lumbar facet syndrome" is common and often indicates severe lumbar spine surgery procedures. It is doubtful whether a painful facet joint (FJ) can be identified by a single FJ block. The aim of this study was to clarify the validity of a single and placebo controlled bilateral FJ blocks using local anesthetics. A prospective single blinded triple cross-over study was performed. 60 patients (31 f, 29 m, mean age 53.2 yrs (22-73)) with chronic low back pain (mean pain persistance 31 months, 6 months of conservative treatment without success) admitted to a local orthopaedic department for surgical or conservative therapy of chronic LBP, were included in the study. Effect on pain reduction (10 point rating scale) was measured. The 60 subjects were divided into six groups with three defined sequences of fluoroscopically guided bilateral monosegmental lumbar FJ test injections in "oblique needle" technique: verum-(local anaesthetic-), placebo-(sodium chloride-) and sham-injection. Carry-over and periodic effects were evaluated and a descriptive and statistical analysis regarding the effectiveness, difference and equality of the FJ injections and the different responses was performed. The results show a high rate of non-response, which documents the lack of reliable and valid predictors for a positive response towards FJ blocks. There was a high rate of placebo reactions noted, including subjects who previously or later reacted positively to verum injections. Equivalence was shown among verum vs. placebo and partly vs. sham also. With regard to test validity criteria, a single intraarticular FJ block with local anesthetics is not useful to detect the pain-responsible FJ and therefore is no valid and reliable diagostic tool to specify indication of lumbar spine surgery. Comparative FJ blocks with local anesthetics and placebo-controls have to be interpretated carefully also, because they solely give no proper diagnosis on FJ being main pain generator.

Automatic detection of the carotid artery boundary on cross-sectional MR image sequences using a circle model guided dynamic programming.

BACKGROUND: Systematic aerobe training has positive effects on the compliance of dedicated arterial walls. The adaptations of the arterial structure and function are associated with the blood flow-induced changes of the wall shear stress which induced vascular remodelling via nitric oxide delivered from the endothelial cell. In order to assess functional changes of the common carotid artery over time in these processes, a precise measurement technique is necessary. Before this study, a reliable, precise, and quick method to perform this work is not present. METHODS: We propose a fully automated algorithm to analyze the cross-sectional area of the carotid artery in MR image sequences. It contains two phases: (1) position detection of the carotid artery, (2) accurate boundary identification of the carotid artery. In the first phase, we use intensity, area size and shape as features to discriminate the carotid artery from other tissues and vessels. In the second phase, the directional gradient, Hough transform, and circle model guided dynamic programming are used to identify the boundary accurately. RESULTS: We test the system stability using contrast degraded images (contrast resolutions range from 50% to 90%). The unsigned error ranges from 2.86% ± 2.24% to 3.03% ± 2.40%. The test of noise degraded images (SNRs range from 16 to 20 dB) shows the unsigned error ranging from 2.63% ± 2.06% to 3.12% ± 2.11%. The test of raw images has an unsigned error 2.56% ± 2.10% compared to the manual tracings. CONCLUSIONS: We have proposed an automated system which is able to detect carotid artery cross sectional boundary in MRI sequences during heart cycles. The accuracy reaches 2.56% ± 2.10% compared to the manual tracings. The system is stable, reliable and results are reproducible.

Poor outcome following bilateral sacroiliac joint fusion for degenerative sacroiliac joint syndrome.

The purpose of this retrospective study was to evaluate the clinical and radiological outcome of bilateral sacroiliac joint (SIJ) fusion, using a new technique, in patients with a chronic SIJ syndrome. Seventeen patients with chronic low back pain, with a positive response to specific diagnostic tests for the SIJ, were considered candidates for bilateral sacroiliac fusion. The surgical indication was based on the results of local anaesthetic joint infiltration, temporary external fixation or bone scan. Ten patients had had previous surgery on the lumbar spine. Bilateral posterior SIJ fusion was performed with internal fixation and decortication of the sacroiliac joint, using a separate approach to each joint. Local bone grafting was performed. At the time of follow-up (on average 39 months after surgery), 3 patients reported moderate or absent pain, 8 marked pain and 6 severe pain. Seven patients showed a symptomatic non-union; union occurred in only 6 cases. Eighteen percent of the patients were satisfied, but in the other 82% the results were not acceptable. Reoperation was performed in 65% of the patients. Our results with bilateral posterior SIJ fusion were disappointing, which may be related with difficulties in patient selection, as well as with surgical technique. Better diagnostic procedures and possibly other surgical techniques might provide more predictable results, but this remains to be demonstrated.

Assessment of femoral component migration in total hip arthroplasty: digital measurements compared to RSA.

The aim of this study was to determine the accuracy of the software system "Düsseldorf Migration Analysis - Femoral Component Analysis" (DMA-FCA) in measuring stem migration in total hip arthroplasty (THA) on digitised anteroposterior radiographs of the pelvis. Bony and implant landmarks on two consecutive radiographs were used for measurements of subsidence and varus-valgus tilt. The accuracy of the method was determined by reference to radiostereometric measurements (RSA). Using specific comparability limits, comparability analysis of radiographs with respect to femoral positioning is possible with DMA. DMA-FCA and RSA measurements were performed after cementless THR in a population of 60 patients aged 38 to 69 years. With a Cronbach's alpha-index of 0.89 and 0.99 for subsidence and 0.90 and 0.98 for classic varus-valgus-tilt, the intraobserver and interobserver reliability for the DMA-FCA-method was calculated as good. Using RSA as reference method, the accuracy of DMA-FCA was calculated to be 2.51 mm for subsidence and 2.49 degrees for varus-valgus-tilt (95% confidence interval). Without comparison to RSA, DMA measured 1.94 mm for subsidence and 2.35 degrees for varus-valgus-tilt. Based on a comparison with RSA, our results show lower accuracy for DMA-FCA than for EBRA-FCA, but DMA-FCA is easier to use in everyday clinical practice. It is hoped that the use of digital measuring methods such as DMA will become standard for long-term observation and will be integrated into clinical routine in the context of quality assurance of THR.