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Noninvasive Evaluation of Bladder Wall Mechanical Properties as a Function of Filling Volume: Potential Application in Bladder Compliance Assessment.

Nenadic I, Mynderse L, Husmann D, Mehrmohammadi M, Bayat M, Singh A, Denis M, Urban M, Alizad A, Fatemi M - PLoS ONE (2016)

Bottom Line: Of particular interest is the shear modulus of bladder wall at different volumes, which we hypothesize, is similar to measuring the compliance characteristics of the bladder.The ex vivo studies showed a high correlation between the UBV parameters and direct pressure measurement (R2 = 0.84-0.99).The results of UBV on healthy volunteers, performed without catheterization, were comparable to a compliant bladder patient.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.

ABSTRACT

Purpose: We propose a novel method to monitor bladder wall mechanical properties as a function of filling volume, with the potential application to bladder compliance assessment. The proposed ultrasound bladder vibrometry (UBV) method uses ultrasound to excite and track Lamb waves on the bladder wall from which its mechanical properties are derived by fitting measurements to an analytical model. Of particular interest is the shear modulus of bladder wall at different volumes, which we hypothesize, is similar to measuring the compliance characteristics of the bladder.

Materials and methods: Three experimental models were used: 1) an ex vivo porcine model where normal and aberrant (stiffened by formalin) bladders underwent evaluation by UBV; 2) an in vivo study to evaluate the performance of UBV on patients with clinically documented compliant and noncompliant bladders undergoing UDS; and 3) a noninvasive UBV protocol to assess bladder compliance using oral hydration and fractionated voiding on three healthy volunteers.

Results: The ex vivo studies showed a high correlation between the UBV parameters and direct pressure measurement (R2 = 0.84-0.99). A similar correlation was observed for 2 patients with compliant and noncompliant bladders (R2 = 0.89-0.99) undergoing UDS detrusor pressure-volume measurements. The results of UBV on healthy volunteers, performed without catheterization, were comparable to a compliant bladder patient.

Conclusion: The utility of UBV as a method to monitor changes in bladder wall mechanical properties is validated by the high correlation with pressure measurements in ex vivo and in vivo patient studies. High correlation UBV and UDS in vivo studies demonstrated the potential of UBV as a bladder compliance assessment tool. Results of studies on healthy volunteers with normal bladders demonstrated that UBV could be performed noninvasively. Further studies on a larger cohort are needed to fully validate the use of UBV as a clinical tool for bladder compliance assessment.

No MeSH data available.


Related in: MedlinePlus

Plots of UBV parameters for the noncompliant bladder patient, compliant bladder patient and 3 healthy human volunteers: mean values of (a) group velocity values and (b) shear modulus as a function of filling volume.
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pone.0157818.g006: Plots of UBV parameters for the noncompliant bladder patient, compliant bladder patient and 3 healthy human volunteers: mean values of (a) group velocity values and (b) shear modulus as a function of filling volume.

Mentions: The mean values of the UBV parameters as a function of filling volume for the 3 healthy volunteers and the two patients (Fig 5B and 5C) are plotted together in Fig 6. Fig 6 shows that the UBV parameters for the volunteers and the compliant bladder patient are relatively low and vary mildly with filling volume. In contrast, the UBV parameters of the noncompliant bladder patient are much higher and rise more rapidly in comparison to the compliant bladder patient and healthy volunteers.


Noninvasive Evaluation of Bladder Wall Mechanical Properties as a Function of Filling Volume: Potential Application in Bladder Compliance Assessment.

Nenadic I, Mynderse L, Husmann D, Mehrmohammadi M, Bayat M, Singh A, Denis M, Urban M, Alizad A, Fatemi M - PLoS ONE (2016)

Plots of UBV parameters for the noncompliant bladder patient, compliant bladder patient and 3 healthy human volunteers: mean values of (a) group velocity values and (b) shear modulus as a function of filling volume.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920425&req=5

pone.0157818.g006: Plots of UBV parameters for the noncompliant bladder patient, compliant bladder patient and 3 healthy human volunteers: mean values of (a) group velocity values and (b) shear modulus as a function of filling volume.
Mentions: The mean values of the UBV parameters as a function of filling volume for the 3 healthy volunteers and the two patients (Fig 5B and 5C) are plotted together in Fig 6. Fig 6 shows that the UBV parameters for the volunteers and the compliant bladder patient are relatively low and vary mildly with filling volume. In contrast, the UBV parameters of the noncompliant bladder patient are much higher and rise more rapidly in comparison to the compliant bladder patient and healthy volunteers.

Bottom Line: Of particular interest is the shear modulus of bladder wall at different volumes, which we hypothesize, is similar to measuring the compliance characteristics of the bladder.The ex vivo studies showed a high correlation between the UBV parameters and direct pressure measurement (R2 = 0.84-0.99).The results of UBV on healthy volunteers, performed without catheterization, were comparable to a compliant bladder patient.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.

ABSTRACT

Purpose: We propose a novel method to monitor bladder wall mechanical properties as a function of filling volume, with the potential application to bladder compliance assessment. The proposed ultrasound bladder vibrometry (UBV) method uses ultrasound to excite and track Lamb waves on the bladder wall from which its mechanical properties are derived by fitting measurements to an analytical model. Of particular interest is the shear modulus of bladder wall at different volumes, which we hypothesize, is similar to measuring the compliance characteristics of the bladder.

Materials and methods: Three experimental models were used: 1) an ex vivo porcine model where normal and aberrant (stiffened by formalin) bladders underwent evaluation by UBV; 2) an in vivo study to evaluate the performance of UBV on patients with clinically documented compliant and noncompliant bladders undergoing UDS; and 3) a noninvasive UBV protocol to assess bladder compliance using oral hydration and fractionated voiding on three healthy volunteers.

Results: The ex vivo studies showed a high correlation between the UBV parameters and direct pressure measurement (R2 = 0.84-0.99). A similar correlation was observed for 2 patients with compliant and noncompliant bladders (R2 = 0.89-0.99) undergoing UDS detrusor pressure-volume measurements. The results of UBV on healthy volunteers, performed without catheterization, were comparable to a compliant bladder patient.

Conclusion: The utility of UBV as a method to monitor changes in bladder wall mechanical properties is validated by the high correlation with pressure measurements in ex vivo and in vivo patient studies. High correlation UBV and UDS in vivo studies demonstrated the potential of UBV as a bladder compliance assessment tool. Results of studies on healthy volunteers with normal bladders demonstrated that UBV could be performed noninvasively. Further studies on a larger cohort are needed to fully validate the use of UBV as a clinical tool for bladder compliance assessment.

No MeSH data available.


Related in: MedlinePlus