Inclusion Criteria:
Individuals with CF:
* Diagnosis of CF
* Signed written informed consent
* ≥3 - 18 years of age, depending on the cooperation and if lung function measurements are possible
Healthy volunteers:
* Signed written informed consent
* Informed consent of participant and if under 18 years, legal representative respectively
* Children and adults with no history of chronic lung disease or acute respiratory infection in the four weeks prior to the study visit
* ≥3 - 18 years of age, depending on the cooperation and if lung function measurements are possible
Exclusion Criteria:
The presence of any one of the following exclusion criteria will lead to exclusion of the participant, for example:
* Women who are pregnant or breast feeding.
* Intention to become pregnant during the course of the study
* Lack of safe contraception, defined as: Female participants of childbearing potential, not using and not willing to continue using a medically reliable method of contraception for the entire study duration, such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices, or who are not using any other method considered sufficiently reliable by the investigator in individual cases.
* Please note that female participants who are surgically sterilised/hysterectomised or post-menopausal for longer than 2 years are not considered as being of child bearing potential.
* Other clinically significant concomitant disease states (e.g. renal failure, hepatic dysfunction, cardiovascular disease, etc.)
* Known or suspected non-compliance, drug or alcohol abuse
* Continuous glucose monitor
* Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, etc. of the participant
* Metal in body, e.g. pacemaker
* Participation in another study with investigational drug within the 30 days preceding and during the present study
* Subjects which are respiratory insufficient to attend on the lung function measurements (oxygen demand)
* Subjects who are unable to perform the MRI without sedation
* Participants which were born preterm (\<36. week of pregnancy)
* Current smokers
In addition for individuals with CF:
* Known diseases other than related to CF
In addition for healthy individuals:
* Current upper respiratory infection (cough, cold, fever) will lead to postponement of the visit to 4 weeks after the end of symptoms
