@article{WojcinskiDupontSchmidtetal.2012,
  author    = {Wojcinski, Sebastian and Dupont, Jennifer and Schmidt, Werner and Cassel, Michael and Hillemanns, Peter},
  title     = {Real-time ultrasound elastography in 180 axillary lymph nodes elasticity distribution in healthy lymph nodes and prediction of breast cancer metastases},
  series = {BMC medical imaging},
  volume    = {12},
  journal   = {BMC medical imaging},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2342},
  doi       = {10.1186/1471-2342-12-35},
  pages     = {10},
  year      = {2012},
  abstract  = {Background: To determine the general appearance of normal axillary lymph nodes (LNs) in real-time tissue sonoelastography and to explore the method's potential value in the prediction of LN metastases. Methods: Axillary LNs in healthy probands (n=165) and metastatic LNs in breast cancer patients (n=15) were examined with palpation, B-mode ultrasound, Doppler and sonoelastography (assessment of the elasticity of the cortex and the medulla). The elasticity distributions were compared and sensitivity (SE) and specificity (SP) were calculated. In an exploratory analysis, positive and negative predictive values (PPV, NPV) were calculated based upon the estimated prevalence of LN metastases in different risk groups. Results: In the elastogram, the LN cortex was significantly harder than the medulla in both healthy (p=0.004) and metastatic LNs (p=0.005). Comparing healthy and metastatic LNs, there was no difference in the elasticity distribution of the medulla (p=0.281), but we found a significantly harder cortex in metastatic LNs (p=0.006). The SE of clinical examination, B-mode ultrasound, Doppler ultrasound and sonoelastography was revealed to be 13.3\%, 40.0\%, 14.3\% and 60.0\%, respectively, and SP was 88.4\%, 96.8\%, 95.6\% and 79.6\%, respectively. The highest SE was achieved by the disjunctive combination of B-mode and elastographic features (cortex >3mm in B-mode or blue cortex in the elastogram, SE=73.3\%). The highest SP was achieved by the conjunctive combination of B-mode ultrasound and elastography (cortex >3mm in B-mode and blue cortex in the elastogram, SP=99.3\%). Conclusions: Sonoelastography is a feasible method to visualize the elasticity distribution of LNs. Moreover, sonoelastography is capable of detecting elasticity differences between the cortex and medulla, and between metastatic and healthy LNs. Therefore, sonoelastography yields additional information about axillary LN status and can improve the PPV, although this method is still experimental.},
  language  = {en}
}
@article{WojcinskiCasselFarrokhetal.2012,
  author    = {Wojcinski, Sebastian and Cassel, Michael and Farrokh, Andre and Soliman, Amr A. and Hille, Ursula and Schmidt, Werner and Degenhardt, Friedrich and Hillemanns, Peter},
  title     = {Variations in the elasticity of breast tissue during the menstrual cycle determined by real-time sonoelastography},
  series = {Journal of ultrasound in medicine},
  volume    = {31},
  journal   = {Journal of ultrasound in medicine},
  number    = {1},
  publisher = {American Institute of Ultrasound in Medicine},
  address   = {Laurel},
  issn      = {0278-4297},
  pages     = {63 -- 72},
  year      = {2012},
  abstract  = {Objectives-The purpose of this study was to determine the dependence of breast tissue elasticity on the menstrual cycle of healthy volunteers by means of real-time sonoelastography. Methods-Twenty-two healthy volunteers (aged 18-33 years) were examined once weekly during two consecutive menstrual cycles using sonoelastography. Group 1 (n = 10) was not taking hormonal medication; group 2 (n = 12) was taking oral contraceptives. Results-The breast parenchyma appeared softer than the dermis and harder than the adipose tissue, and elasticity varied over the menstrual cycle and between groups. Group 1 (no hormone intake) showed continuously increasing elasticity with relatively soft breast parenchyma in the menstrual and follicular phases and harder parenchyma in the luteal phase (P = .012). Group 2 (oral contraceptives) showed no statistically significant changes in breast parenchymal elasticity according to sonoelastography. The parenchyma was generally softer in group 1 compared with group 2 throughout the menstrual cycle (P = .033). The dermis, the subcutaneous adipose tissue, and the pectoralis major muscle showed no changes in elasticity. Comparison of measurements made during the first and the second menstrual cycles showed similar patterns of elasticity in both groups. Conclusions-Sonoelastography is a reproducible method that can be used to determine the dependence of breast parenchyma elasticity on the menstrual cycle and on the intake of hormonal contraceptives.},
  language  = {en}
}
@article{WahmkowCasselMayeretal.2017,
  author    = {Wahmkow, Gunnar and Cassel, Michael and Mayer, Frank and Baur, Heiner},
  title     = {Effects of different medial arch support heights on rearfoot kinematics},
  series = {PLoS one},
  volume    = {12},
  journal   = {PLoS one},
  number    = {3},
  publisher = {PLoS},
  address   = {Lawrence, Kan.},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0172334},
  year      = {2017},
  abstract  = {Background Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait. Methods Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95\% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05). Results Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95\% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95\% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high. Conclusion Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait.},
  language  = {en}
}
@article{ScharhagRosenbergerWochatzOttoetal.2014,
  author    = {Scharhag-Rosenberger, Friederike and Wochatz, Monique and Otto, Christoph and Cassel, Michael and Mayer, Frank and Scharhag, J{\"u}rgen},
  title     = {Blood lactate concentrations are mildly affected by mobile gas exchange measurements},
  series = {International journal of sports medicine},
  volume    = {35},
  journal   = {International journal of sports medicine},
  number    = {7},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0033-1354386},
  pages     = {590 -- 594},
  year      = {2014},
  abstract  = {We sought to investigate the effects of wearing a mobile respiratory gas analysis system during a treadmill test on blood lactate (bLa) concentrations and commonly applied bLa thresholds. A total of 16 recreational athletes (31 +/- 3 years, V0205: 58 6 ml min(-1)-kg(-1)) performed one multistage treadmill test with and one without gas exchange measurements (GEM and noGEM). The whole bLa curve, the lactate threshold (LT), the individual anaerobic thresholds according to Stegmann(IAT(sr)) and Dickhuth (IAT(Di)), and a fixed bLa concentration of 4 mmob.l(-1) (OBLA) were evaluated. The bLa curve was shifted slightly leftward in GEM compared to noGEM (P<0.05), whereas the heart rate response was not different between conditions (P= 0.89). There was no difference between GEM and noGEM for LT (2.61 +/- 0.34 vs. 2.64 +/- 0.39 m(-1) s(-1) P=0.49) and IAT(st) (3.47 +/- 0.42 vs. 3.55 +/- 0.47m-s(-1), P=0.12). However, IATD(Di) (3.57 +/- 0.39 vs. 3.66 +/- 0.44m-s(-1), P<0.01) and OBLA (3.85 +/- 0.46 vs. 3.96 +/- 0.47m-s-1, P<0.01) occurred at slower running velocities in GEM. The bLa response to treadmill tests is mildly affected by wearing a mobile gas analysis system. This also applies to bLa thresholds located at higher exercise intensities. While the magnitude of the effects is of little importance for recreational athletes, it might be relevant for elite athletes and scientific studies.},
  language  = {en}
}
@article{ScharhagRosenbergerCarlsohnCasseletal.2011,
  author    = {Scharhag-Rosenberger, Friederike and Carlsohn, Anja and Cassel, Michael and Mayer, Frank and Scharhag, J{\"u}rgen},
  title     = {How to test maximal oxygen uptake a study on timing and testing procedure of a supramaximal verification test},
  series = {Applied physiology, nutrition, and metabolism = Physiologie appliqu{\´e}e, nutrition et m{\´e}tabolisme},
  volume    = {36},
  journal   = {Applied physiology, nutrition, and metabolism = Physiologie appliqu{\´e}e, nutrition et m{\´e}tabolisme},
  number    = {1},
  publisher = {NRC Research Press},
  address   = {Ottawa},
  issn      = {1715-5312},
  doi       = {10.1139/H10-099},
  pages     = {153 -- 160},
  year      = {2011},
  abstract  = {On utilise de plus en plus les tests de verification pour confirmer l'atteinte du consommation d'oxygene maximale (VO(2 max)). Toutefois, le moment et les methodes d'evaluation varient d'un groupe de travail a l'autre. Les objectifs de cette etude sont de constater si on peut administrer un test de verification apres un test d'effort progressif ou s'il est preferable de le faire une autre journee et si on peut determiner le VO(2 max) tout de meme lors de la premiere seance chez des sujets ne repondant pas au critere de verification. Quarante sujets (age, 24 +/- 4 ans; VO(2 max), 50 +/- 7 mL center dot min(-1)center dot kg(-1)) participent a un test d'effort progressif sur tapis roulant et, 10 min plus tard, a un test de verification (VerifDay1) a 110 \% de la velocite maximale (v(max)). Le critere de verification est un VO(2) de pointe au VerifDay1 < 5,5 \% a la valeur retenue au test d'effort progressif. Les sujets ne repondant pas au critere de verification passent un autre test de verification, mais a 115 \% du VerifDay1', et ce, 10 min plus tard pour confirmer le VO(2) de pointe du VerifDay1 en tant que VO(2 max). Tous les autres sujets repassent le VerifDay1 a un jour different (VerifDay2). Six sujets sur quarante ne repondent pas au critere de verification. Chez quatre d'entre eux, on confirme l'atteinte du VO(2 max) au VerifDay1'. Le VO(2) de pointe au VerifDay1 est equivalent a celui du VerifDay2 (3722 +/- 991 mL center dot min(-1) comparativement a 3752 +/- 995 mL center dot min(-1), p = 0,56), mais le temps jusqu'a l'epuisement est significativement plus long au VerifDay2 (2:06 +/- 0:22 min:s comparativement a 2:42 +/- 0:38 min:s, p < 0,001, n = 34). Le VO(2) de pointe obtenu au test de verification ne semble pas conditionne par un test d'effort progressif maximal prealable. On peut donc realiser le test d'effort progressif et le test de verification lors de la meme seance d'evaluation. Chez presque tous les individus ne repondant pas au critere de verification, on peut determiner le VO(2 max) au moyen d'un autre test de verification plus intense.},
  language  = {en}
}
@article{RischWochatzMesserschmidtetal.2017,
  author    = {Risch, Lucie and Wochatz, Monique and Messerschmidt, Janin and Engel, Tilman and Mayer, Frank and Cassel, Michael},
  title     = {Reliability of evaluating achilles tendon vascularization assessed with doppler ultrasound advanced dynamic flow},
  series = {Journal of ultrasound in medicine},
  volume    = {37},
  journal   = {Journal of ultrasound in medicine},
  number    = {3},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0278-4297},
  doi       = {10.1002/jum.14414},
  pages     = {737 -- 744},
  year      = {2017},
  abstract  = {The reliability of quantifying intratendinous vascularization by high-sensitivity Doppler ultrasound advanced dynamic flow has not been examined yet. Therefore, this study aimed to investigate the intraobserver and interobserver reliability of evaluating Achilles tendon vascularization by advanced dynamic flow using established scoring systems. Methods-Three investigators evaluated vascularization in 67 recordings in a test-retest design, applying the Ohberg score, a modified Ohberg score, and a counting score. Intraobserver and interobserver agreement for the Ohberg score and modified Ohberg score was analyzed by the Cohen kappa and Fleiss kappa coefficients (absolute), Kendall tau b coefficient, and Kendall coefficient of concordance (W; relative). The reliability of the counting score was analyzed by intraclass correlation coefficients (ICC) 2.1 and 3.1, the standard error of measurement (SEM), and Bland-Altman analysis (bias and limits of agreement [LoA]). Results-Intraobserver and interobserver agreement (absolute/relative) ranged from 0.61 to 0.87/0.87 to 0.95 and 0.11 to 0.66/0.76 to 0.89 for the Ohberg score and from 0.81 to 0.87/0.92 to 0.95 and 0.64 to 0.80/0.88 to 0.93 for the modified Ohberg score, respectively. The counting score revealed an intraobserver ICC of 0.94 to 0.97 (SEM, 1.0-1.5; bias, -1; and LoA, 3-4 vessels). The interobserver ICC for the counting score ranged from 0.91 to 0.98 (SEM, 1.0-1.9; bias, 0; and LoA, 3-5 vessels). Conclusions-The modified Ohberg score and counting score showed excellent reliability and seem convenient for research and clinical practice. The Ohberg score revealed decent intraobserver but unexpected low interobserver reliability and therefore cannot be recommended.},
  language  = {en}
}
@article{RischStollSchomoelleretal.2020,
  author    = {Risch, Lucie and Stoll, Josefine and Schom{\"o}ller, Anne and Engel, Tilman and Mayer, Frank and Cassel, Michael},
  title     = {Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons},
  series = {Frontiers in physiology},
  volume    = {12},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne, Schweiz},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2021.617497},
  pages     = {1 -- 8},
  year      = {2020},
  abstract  = {Objective: This study investigated intraindividual differences of intratendinous blood flow (IBF) in response to running exercise in participants with Achilles tendinopathy. Design: This is a cross-sectional study. Setting: The study was conducted at the University Outpatient Clinic. Participants: Sonographic detectable intratendinous blood flow was examined in symptomatic and contralateral asymptomatic Achilles tendons of 19 participants (42 ± 13 years, 178 ± 10 cm, 76 ± 12 kg, VISA-A 75 ± 16) with clinically diagnosed unilateral Achilles tendinopathy and sonographic evident tendinosis. Intervention: IBF was assessed using Doppler ultrasound "Advanced Dynamic Flow" before (Upre) and 5, 30, 60, and 120 min (U5-U120) after a standardized submaximal constant load run. Main Outcome Measure: IBF was quantified by counting the number (n) of vessels in each tendon. Results: At Upre, IBF was higher in symptomatic compared with asymptomatic tendons [mean 6.3 (95\% CI: 2.8-9.9) and 1.7 (0.4-2.9), p < 0.01]. Overall, 63\% of symptomatic and 47\% of asymptomatic Achilles tendons responded to exercise, whereas 16 and 11\% showed persisting IBF and 21 and 42\% remained avascular throughout the investigation. At U5, IBF increased in both symptomatic and asymptomatic tendons [difference to baseline: 2.4 (0.3-4.5) and 0.9 (0.5-1.4), p = 0.05]. At U30 to U120, IBF was still increased in symptomatic but not in asymptomatic tendons [mean difference to baseline: 1.9 (0.8-2.9) and 0.1 (-0.9 to 1.2), p < 0.01]. Conclusion: Irrespective of pathology, 47-63\% of Achilles tendons responded to exercise with an immediate acute physiological IBF increase by an average of one to two vessels ("responders"). A higher amount of baseline IBF (approximately five vessels) and a prolonged exercise-induced IBF response found in symptomatic ATs indicate a pain-associated altered intratendinous "neovascularization."},
  language  = {en}
}
@article{RischMayerCassel2021,
  author    = {Risch, Lucie and Mayer, Frank and Cassel, Michael},
  title     = {Doppler flow response following running exercise differs between healthy and tendinopathic Achilles tendons},
  series = {Frontiers in Physiology},
  volume    = {12},
  journal   = {Frontiers in Physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2021.650507},
  pages     = {10},
  year      = {2021},
  abstract  = {Background: The relationship between exercise-induced intratendinous blood flow (IBF) and tendon pathology or training exposure is unclear. Objective: This study investigates the acute effect of running exercise on sonographic detectable IBF in healthy and tendinopathic Achilles tendons (ATs) of runners and recreational participants. Methods: 48 participants (43 ± 13 years, 176 ± 9 cm, 75 ± 11 kg) performed a standardized submaximal 30-min constant load treadmill run with Doppler ultrasound "Advanced dynamic flow" examinations before (Upre) and 5, 30, 60, and 120 min (U5-U120) afterward. Included were runners (>30 km/week) and recreational participants (<10 km/week) with healthy (Hrun, n = 10; Hrec, n = 15) or tendinopathic (Trun, n = 13; Trec, n = 10) ATs. IBF was assessed by counting number [n] of intratendinous vessels. IBF data are presented descriptively (\%, median [minimum to maximum range] for baseline-IBF and IBF-difference post-exercise). Statistical differences for group and time point IBF and IBF changes were analyzed with Friedman and Kruskal-Wallis ANOVA (α = 0.05). Results: At baseline, IBF was detected in 40\% (3 [1-6]) of Hrun, in 53\% (4 [1-5]) of Hrec, in 85\% (3 [1-25]) of Trun, and 70\% (10 [2-30]) of Trec. At U5 IBF responded to exercise in 30\% (3 [-1-9]) of Hrun, in 53\% (4 [-2-6]) of Hrec, in 70\% (4 [-10-10]) of Trun, and in 80\% (5 [1-10]) of Trec. While IBF in 80\% of healthy responding ATs returned to baseline at U30, IBF remained elevated until U120 in 60\% of tendinopathic ATs. Within groups, IBF changes from Upre-U120 were significant for Hrec (p < 0.01), Trun (p = 0.05), and Trec (p < 0.01). Between groups, IBF changes in consecutive examinations were not significantly different (p > 0.05) but IBF-level was significantly higher at all measurement time points in tendinopathic versus healthy ATs (p < 0.05). Conclusion: Irrespective of training status and tendon pathology, running leads to an immediate increase of IBF in responding tendons. This increase occurs shortly in healthy and prolonged in tendinopathic ATs. Training exposure does not alter IBF occurrence, but IBF level is elevated in tendon pathology. While an immediate exercise-induced IBF increase is a physiological response, prolonged IBF is considered a pathological finding associated with Achilles tendinopathy.},
  language  = {en}
}
@article{RischCasselMayer2017,
  author    = {Risch, Lucie and Cassel, Michael and Mayer, Frank},
  title     = {Acute effect of running exercise on physiological Achilles tendon blood flow},
  series = {Scandinavian journal of medicine \& science in sports},
  volume    = {28},
  journal   = {Scandinavian journal of medicine \& science in sports},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0905-7188},
  doi       = {10.1111/sms.12874},
  pages     = {138 -- 143},
  year      = {2017},
  abstract  = {Sonographically detectable intratendinous blood flow (IBF) is found in 50\%-88\% of Achilles tendinopathy patients as well as in up to 35\% of asymptomatic Achilles tendons (AT). Although IBF is frequently associated with tendon pathology, it may also represent a physiological regulation, for example, due to increased blood flow in response to exercise. Therefore, this study aimed to investigate the acute effects of a standardized running exercise protocol on IBF assessed with Doppler ultrasound (DU) Advanced dynamic flow in healthy ATs. 10 recreationally active adults (5 f, 5m; 29 +/- 3years, 1.72 +/- 0.12m, 68 +/- 16kg, physical activity 206 +/- 145minute/wk) with no history of AT pain and inconspicious tendon structure performed 3 treadmill running tasks on separate days (M1-3) with DU examinations directly before and 5, 30, 60, and 120minutes after exercise. At M1, an incremental exercise test was used to determine the individual anaerobic threshold (IAT). At M2 and M3, participants performed 30-minute submaximal constant load tests (CL1/CL2) with an intensity 5\% below IAT. IBF in each tendon was quantified by counting the number of vessels. IBF increased in five ATs from no vessels at baseline to one to four vessels solely detectable 5minutes after CL1 or CL2. One AT had persisting IBF (three vessels) throughout all examinations. Fourteen ATs revealed no IBF at all. Prolonged running led to a physiological, temporary appearance of IBF in 25\% of asymptomatic ATs. To avoid exercise-induced IBF in clinical practice, DU examinations should be performed after 30minutes of rest.},
  language  = {en}
}
@article{RectorIntziegianniMuelleretal.2017,
  author    = {Rector, Michael V. and Intziegianni, Konstantina and M{\"u}ller, Steffen and Mayer, Frank and Cassel, Michael},
  title     = {Reproducibility of an ankle joint rotation correction method for assessment of Achilles tendon elongation},
  series = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  volume    = {25},
  journal   = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  number    = {1},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {0959-3020},
  doi       = {10.3233/IES-160644},
  pages     = {47 -- 52},
  year      = {2017},
  abstract  = {BACKGROUND: The Achilles tendon (AT) requires optimal material and mechanical properties to function properly. Calculation of these properties depends on accurate measurement of input parameters (i.e. tendon elongation). However, the measurement of AT elongation with ultrasound during maximum voluntary isometric contraction (MVIC) is overestimated by ankle joint rotation (AJR). Methods to correct the influence of this rotation on AT elongation exist, yet their reproducibility in clinical settings is unknown. OBJECTIVE: To evaluate the test-retest reproducibility of AT elongation during MVIC after AJR correction. METHODS: Ten participants attended test and retest measurements where they performed plantar-flexion MVIC on a dynamometer. Simultaneously, ultrasound recorded AT elongation as the displacement of the medial gastrocnemius-myotendinous junction, while an electrogoniometer measured AJR. The ankle was then passively rotated to the AJR achieved during MVIC and AT elongation again determined. Elongation was corrected by subtracting this passive AT elongation from the total AT elongation during MVIC. Reproducibility was evaluated using ICC (2.1), test-retest variability (TRV, \%), Bland-Altman analyses (Bias +/- LoA [1.96*SD]) and standard error of the measurement (SEM). RESULTS: Corrected AT elongation reproducibility exhibited an ICC = 0.79, SEM = 0.2 cm and TRV = 20 +/- 19\%. Bias +/- LoA were determined to be 0.0 +/- 0.8 cm. CONCLUSIONS: Using this ultrasound and electrogoniometer-based method, corrected AT elongation can be assessed reproducibly.},
  language  = {en}
}