Adult 1 Aged 1 Bladder wall Bladder wall elasticity 1 Body positions 1 Compliance 1 Detrusor thickness 1 Elasticity 1 Elasticity Imaging Techniques 1 Female 1 Group velocities 1 Humans 1 Hydrodynamics 1 Male 1 Middle Aged 1 Parameter estimation 1 Patient Positioning 1 Pilot Projects 1 Prospective Studies 1 Sitting Position 1 Sitting positions 1 Supine Position 1 Transabdominal ultrasound 1 Ultrasonics 1 Ultrasound bladder vibrometry 1 Ultrasound measurement 1 Urinary Bladder 1 Vibrometry 1 Young Adult 1 adult 1