title: Noninvasive 2-dimensional monitoring of strain in the detrusor muscle in patients with lower urinary tract symptoms using ultrasound strain imaging.
abstract: OBJECTIVE
  Pressure flow studies and filling cystometry are currently the standard diagnostic urodynamic tests for lower urinary tract symptoms. A noninvasive ultrasound based method for 2-dimensional monitoring of deformation (or strain) in the detrusor muscle may provide insight into detrusor muscle structural and dynamic properties related to pressure in physiological and disease conditions.
  
  
  METHODS
  In a male patient population with lower urinary tract symptoms, strain in the detrusor muscle (perpendicular to the bladder wall) was estimated based on 2-dimensional radio frequency ultrasound imaging. The estimated strain was correlated to detrusor pressure and urinary flow rate using Spearman's correlation coefficient.
  
  
  RESULTS
  Twenty men (mean ± SD age 66 ± 6 years) with lower urinary tract symptoms were included in the study. Ultrasound data acquisition was successful in 13 patients. In 7 patients data acquisition failed due to out-of-plane motion of the bladder wall during voiding or as a result of patient movement during acquisition. The estimated strain correlated positively with detrusor pressure in the 5 patients with an isovolumetric detrusor contraction (Spearman's 0.70-0.99, p <0.05). Of 8 patients with urinary voiding during detrusor muscle contraction this correlation was significantly positive in 5 patients (Spearman's 0.52-0.81, p <0.05).
  
  
  CONCLUSIONS
  In 13 of 20 patients with lower urinary tract symptoms we demonstrated that strain in the detrusor muscle can be estimated using ultrasound imaging. The estimated strain correlated positively with the detrusor pressure. Optimal results were obtained in the pre-voiding phase, suggesting that ultrasound strain imaging can possibly be used to monitor detrusor muscle activity in real time.
authors.affiliation: Medical UltraSound Imaging Center, Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. t.idzenga@rad.umcn.nl
authors.forename: Tim
authors.initials: T
authors.lastname: Idzenga
authors.forename: Fawzy
authors.initials: F
authors.lastname: Farag
authors.forename: John
authors.initials: J
authors.lastname: Heesakkers
authors.forename: Wout
authors.initials: W
authors.lastname: Feitz
authors.forename: Chris L
authors.initials: CL
authors.lastname: de Korte
mesh_terms: D000368:Aged; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D009130:Muscle, Smooth / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014463:Ultrasonography / Q000379:methods; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014563:Urodynamics