Biochemical cartilage alteration and unexpected signal recovery in T2* mapping observed in ankle joints with mobile MRI during a transcontinental multistage footrace over 4486 km.

OBJECTIVE: The effect of ultra-long distance running on the ankle cartilage with regard to biochemical changes, thickness and lesions is examined in the progress of a transcontinental ultramarathon over 4486 km. METHOD: In an observational field study, repeated follow-up scanning of 22 participants of the TransEurope FootRace (TEFR) with a 1.5 T MRI mounted on a mobile unit was performed. For quantitative biochemical and structural evaluation of cartilage a fast low angle shot (FLASH) T2* weighted gradient-echo (GRE)-, a turbo-inversion-recovery-magnitude (TIRM)- and a fat-saturated proton density (PD)-weighted sequence were utilized. Statistical analysis of cartilage T2* and thickness changes was obtained on the 13 finishers (12 male, mean age 45.4 years, BMI 23.5 kg/m²). None of the nine non-finisher (eight male, mean age 53.8 years, BMI 23.4 kg/m²) stopped the race due to ankle problems. RESULTS: From a mean of 17.0 ms for tibial plafond and 18.0 ms for talar dome articular cartilage at baseline, nearly all observed regions of interest (ROIs) of the ankle joint cartilage showed a significant T2*-signal increase (25.6% in mean), with standard error ranging from 19% to 33% within the first 2500 km of the ultra-marathon. This initial signal behavior was followed by a signal decrease. This signal recovery (30.6% of initial increase) showed a large effect size. No significant morphological or cartilage thickness changes (at baseline 2.9 mm) were observed. CONCLUSION: After initial T2*-increase during the first 2000-2500 km, a subsequent T2*-decrease indicates the ability of the normal cartilage matrix to partially regenerate under ongoing multistage ultramarathon burden in the ankle joints.

[MRI changes of Achilles tendon and hindfoot in experienced runners and beginners during training and after a (half)-marathon competition]. / MR-tomografische Veränderungen an Achillessehne und Rückfuß von Laufanfängern und Lauferfahrenen im Trainingsverlauf und nach einem (Halb-)Marathon.

BACKGROUND: Marathon running is gaining in popularity. Its benefits regarding the cardiovascular system as well as the metabolism are beyond doubt. However, whether or not there are detrimental side effects to the musculoskeletal system such as wear and tear is an unsolved question. We therefore prospectively looked at beginners and experienced runners at a city marathon during training and after the competition for lesions to the Achilles tendon (AT) or hindfoot. MATERIAL AND METHOD: 73 healthy subjects were prospectively included in our study. They were recruited from the applicants of the city marathon or half-marathon. They underwent an initial clinical orthopaedic as well as three magnetic resonance (MRI) examinations. The MRI were conducted at the time point of study enrolment, near the end of training and directly (up to 72 hours) after the run. MRI evaluation (fat saturated T (2)-weighted sagittal STIR sequence) was performed by two independent experienced radiologists blinded to the clinical context. The results were compared for subgroups of runners, also a factorial analysis was performed. Statistical results were deemed significant for p ≤ 0.05. RESULTS: 32 women and 41 men were included. In the end there were 53 finishers and 20 non-finishers; 28 seasoned runners and 25 novices. 57 runners had no foot complaints, while 14 had foot pain during training and 13 during the marathon. Mean body weight was 71.6 kg, height was 173 cm, age was 40.2 years. Mean AT diameter was 7.0 mm and showed no change during training or after the marathon. There was no significant influence of gender on other variables investigated. There was a significant and positive correlation between AT diameter and weight (r = 0.37), also AT and height (r = 0.34), while there was negative correlation between height and signal intensity of calcaneus (r = -0.50). The signal intensity of the AT decreased during training. The signal intensity of the calcaneus decreased from inclusion until after the marathon, while the mean retrocalcanear bursa volume and AT lesion volume increased. Some of the non-finishers stopped the training because of orthopaedic symptoms. These runners generally had an apparent lesion visible in their initial MRI examination. Regarding the factorial analysis of the data, there were no risk factors predicting non-finishing or development of new lesions to be detected. Interrater reliability was moderate for retrocalcanear bursa, while it was good to excellent for AT diameter and calcaneus MR signal intensity. CONCLUSION: In our sample of primarily asymptomatic German runners, the AT diameter was higher than in symptomatic American patients. The diameter did not change during training or after the marathon. Non-finishers with orthopaedic reasons generally had a lesion on MRI in the initial examination. Apart from this, no new lesions to the AT or hindfoot are to be expected during normal training. Adaptive processes seem to be the main effect of this training.

[Interobserver agreement in the assessment of pulmonary infiltrates on chest radiography in community-acquired pneumonia]. / Detektion pneumonischer Infiltrate bei ambulant erworbener Pneumonie: Ubereinstimmung in der Befundung der Röntgen-Thoraxaufnahme.

PURPOSE: To assess interobserver agreement (IOA) in the diagnosis of pulmonary infiltrates on chest x-rays for patients with community-acquired pneumonia (CAP). MATERIALS AND METHODS: From 7/2002 to 12/2005, 806 adults with CAP were included in the multicenter study "CAPNETZ" (7 hospitals). Inclusion criteria were clinical signs of pneumonia and pulmonary opacification on chest x-rays. Each x-ray was reevaluated by two radiologists from the university hospital in consensus reading against the interpreter at the referring hospital in regard to: presence of infiltrate (yes/no/equivocal), transparency (50%), localization, and pattern of infiltrates (alveolar/interstitial). The following parameters were documented: digital or film radiography, hospitalization, fever, findings of auscultation, microbiological findings. RESULTS: The overall IOA concerning the detection of infiltrates was 77.7% (n=626; CI 0.75-0.81), the infiltrates were not verified in 16.4% (n=132) by the referring radiologist with equivocal findings in 5.9% (n=48). The IOA of the different clinical centers varied between 63.2% (n=38, CI 0.48-0.78) and 92.3% (n=65, CI 0.86-0.99). The IOA for the diagnosis of infiltrates was significantly higher for inpatients with 82.6% (n=546; CI 0.80-0.85) than for outpatients with 55.2 % (n=80; CI 0.47-0.63), p<0.0001. The IOA of infiltrates with a transparency >50% was 95.1% (n=215; CI 0.92-0.98) versus 80.4% (n=403; CI 0.77-0.84) for infiltrates with a transparency >50% (p<0.0001). In patients with positive auscultation, the IOA was higher (p=0,034). Chest x-rays of patients with antibiotic therapy or an alveolar infiltrate showed more equivocal findings compared to patients without these features. CONCLUSION: There is considerable interobserver variability in the diagnosis of pulmonary infiltrates on chest radiographs. The IOA is higher in more opaque infiltrates, positive auscultation and inpatients.

Effects of sodium concentration and osmolality on water and electrolyte absorption form the intact human colon.

The influence of sodium concentration and osmolality on net water and monovalent electrolyte absorption from or secretion into the intact human colon was studied in healthy volunteers. WHEN ISOTONIC SOLUTIONS CONTAINING NACL AND/OR MANNITOL WERE INFUSED INTO THE COLON: (a) a direct linear relationship between luminal sodium concentration (in the range of 23-150 mEq/liter) and rate of net water, sodium, and chloride absorption was found. No water absorption was found when sodium concentration in the luminal fluid was below 20 mEq/liter; (b) water and sodium absorption from the isotonic test solutions was not enhanced by addition of 80-250 mg/100 ml of glucose; and (c) the rate of water and sodium absorption was decreased markedly when chloride was replaced by bicarbonate in the test solution. WHEN THE COLON WAS PERFUSED WITH HYPERTONIC TEST SOLUTIONS CONTAINING NACL AND MANNITOL OR UREA: (a) water was absorbed from hypertonic NaCl solutions against a lumen-to-blood osmotic gradient of 50 mOsm/kg; (b) when the osmolality of the mannitol solution was increased, water entered the colonic lumen at a more rapid rate. The relationship between the rate of water entering the colon and the osmolality of the test solution was a parabolic one; (c) sodium and chloride entered the colonic lumen at a rate that was lineraly related to that of water entrance when the lumen-to-blood osmotic gradient exceeded 150 mOsm/kg; (d) water flow into the colonic lumen was identical when equimolar urea or mannitol solutions were infused; (e) neither urea nor mannitol was absorbed in significant amounts from the hypertonic solutions; and (f) our results suggest that the equivalent pore radius of the human colon is smaller than the molecular radius of urea (2.3 A).