0000000000114524
AUTHOR
Marc D. Schmittner
Aktive Muskeldehntestung der ischiocruralen Muskulatur: Referenzwerte und Einflussfaktoren
Einleitung: Eine verminderte Dehnfahigkeit der ischiocruralen Muskulatur fuhrt zu einem erhohten Verletzungsrisiko. Ziel ist deshalb die Herstellung einer muskularen Balance. Der Active-Knee-Extension-Test (AKE) uberpruft die Dehnfahigkeit der ischiocruralen Muskulatur. Da die bislang verfugbaren „Referenzwerte“ einem Kollektiv von wenigen mannlichen Probanden entstammen, ist deren Aussagekraft nur eingeschrankt verwertbar. Ziel der vorliegenden Studie ist daher die Erhebung von Referenzwerten an einem grosen gemischtgeschlechtlichen Probandenkollektiv gesunder Fitnesssportler sowie die Ermittlung von Einflussfaktoren auf die aktive Dehnfahigkeit der ischiocruralen Muskulatur. Material und …
Measurements of alveolar pO2 using 19F-MRI in partial liquid ventilation.
Rationale and Objectives: Partial liquid ventilation using Perfluorcarbon (PFC) is an innovative treatment of acute respiratory distress syndrome. However, the underlying mechanisms are not totally clear. The aim was to investigate the distribution of oxygen partial pressure within the PFC-filled lung (ppO 2 ). Methods: Nine pigs underwent partial liquid ventilation, receiving 20 mL PFC/kg bodyweight (bw). Measurements were obtained by a chemical shift selective TurboFLASH sequence at different axial lung levels. ppO 2 was calculated from 1 9 F-MRI by nonlinear curve T 1 -fitting technique after noise correction. Results: Quantification and distribution of ppO 2 was performed successfully. …
19F-MRI of perflubron for measurement of oxygen partial pressure in porcine lungs during partial liquid ventilation
A method for in vivo measurement of oxygen partial pressure (pO2) in porcine lungs during partial liquid ventilation (PLV) with perflubron (PFOB) was developed. A pulse sequence for high-resolution MRI of the distribution of PFOB in the lung after intratracheal administration was developed as well. Moreover, quantitative measurements of longitudinal relaxation time T(1) of (19)F resonances for assessment of regional pO2 are described. Due to the need to acquire data during a single expiratory breathhold, only low SNRs were achieved in vivo. Therefore, simulations were performed to investigate the influence of background noise on T(1) values calculated from data with low SNR. Based on these …
Ventilation-Perfusion Ratio in Perflubron During Partial Liquid Ventilation
BACKGROUND: Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detec…