Feasibility of approximate measurement of bladder volume in male patients using the Lilium α-200 portable ultrasound bladder scanner

Can portable ultrasound bladder scanner be applied to young children less than three years old?

INTRODUCTION

The bladder scanner (BS), a portable ultrasound device specialized in bladder volume measurement, has been developed and applied to clinical assessment of postvoid residual urine, which is a requisite in evaluating patients with voiding dysfunction. However, experiences in the application of the BS to the pediatric population remain limited despite commonly encountered reluctance to catheterization. This prospective observational study aimed to evaluate the correlation and accuracy of the newly developed pediatric module of the BS (BioCon-900) in measuring bladder volume in children 0-6 years old.

MATERIALS AND METHODS

This study included 29 patients scheduled to undergo preventive untethering for their spinal dysraphism. When they undergo cystometry for the confirmation of normal neurologic function, bladder volume was measured by BS when recorded volume infusion reached each quartile of the age-adjusted estimated bladder capacity (EBC). The difference (bias) between measured and infused volume was expressed as a percentage of EBC (%EBC). The correlation coefficient and the Bland-Altman plot were obtained to determine the discriminating power and accuracy, respectively. The acceptable limit was set as 30%EBC.

RESULTS

A strong correlation between the measured and infused volume (r = 0.95, P < 0.001) was found for the entire age range. This excellent correlation remained comparable between children less than three years and the older ones. Bladder volume tended to be overestimated, and the mean bias was 33 ± 22.3%EBC, and it became higher with increasing quartiles. The accuracy was acceptable in all ranges of measurement in the older group and first and second quartiles in the younger one.

DISCUSSION

We have first evaluated the potential use of BS in 0-3 years old children and compared the results with 4-6-year-old children in whom the accuracy of BS has been demonstrated. The strong point of our study was the inclusion of data spanning all quartiles of bladder volume. The use of infused volume as reference enabled us to assess the accuracy in a more precise way than the use of ultrasound. Despite the good discriminating power, the accuracy was not acceptable in higher quartiles in the younger group. If the trend of overestimation especially higher volume, could be understood prior to measurement, it would be helpful to assume the real val.

CONCLUSIONS

The children's module in BS showed excellent discriminating power and generally acceptable accuracy in more than four-year-old children. This may lose accuracy in higher quartiles among less than three years old children.

Improvement in bladder volume reproducibility using A-mode portable ultrasound bladder scanner in moderate-hypofractionated volumetric modulated arc therapy for prostate cancer patients

Purpose

This study introduced an A‐mode portable ultrasound bladder scanner, the Lilium® α‐200 (here after Lilium; Lilium Otsuka, Kanagawa, Japan), for the treatment of prostate cancer patients with hypofractionated volumetric modulated arc therapy to improve the reproducibility of bladder volume (BV).

Materials and methods

Thirty patients were advised to maintain full BV prior to computed tomography (CT) simulation and daily treatment. Among these, the BV of 15 patients was measured using Lilium until a BV of 80% in the simulation was achieved (with the Lilium group). Daily cone‐beam CT (CBCT) was performed for treatment. The correlation between BV measured by CBCT and Lilium was assessed. The differences in the BV and dosimetric parameters of the bladder in the CBCT versus planning CT were compared between the groups with and without Lilium.

Results

There was a significantly strong relationship (r = 0.796, p < 0.05) between the BVs measured using CBCT and Lilium. The relative BV ratios to simulation CT < 0.5 and > 2 were observed in 10.3% and 12.7%, respectively, of treatment sessions without Lilium group, while these ratios were 1% and 2.8%, respectively, in the Lilium group. The mean absolute difference in the range of V_30Gy to V_40Gy without Lilium sessions was significantly larger (p < 0.05) than that in the Lilium group.

Conclusion

The use of the A‐mode portable ultrasound bladder scanner significantly improved the reproducibility of the BV, resulting in few variations in the dosimetric parameters for the bladder.

A Small 8-Electrode Electrical Impedance Measurement Device for Urine Volume Estimation in the Bladder

Urinary incontinence is prevalent among elderly people. Recent studies have demonstrated the effectiveness of continence care based on urine volume measurement for elderly people who maintain their urinary storage function, but have difficulty feeling bladder fullness owing to dementia or neurological disorders. Electrical impedance measurement is a feasible technique that can be adopted in the diaper or underwear for continuous and unobtrusive urine volume measurements. We developed a small sensor device that can measure electrical impedance with a resolution of 0.017 Ω, which is sufficiently small to capture abdominal impedance alterations triggered by urine accumulation. The results obtained from a preliminary feasibility test in a young healthy volunteer suggested that the 8-electrode electrical impedance measurement with linear regression can estimate urine volume in the bladder in humans for the first time.Clinical Relevance-Continence care for elderly people is essential; however, it is a huge burden for nurses and caregivers, because it involves taking patients to the toilet or changing diapers. This study proposes a continuous and unobtrusive measurement device for urine volume in the bladder. Via continuous monitoring and bladder fullness alert, the device will enable nurses and caregivers to provide personalized continence care without hindering their routine care.

Feasibility of the Lilium α-200 portable ultrasound bladder scanner for accurate bladder volume measurement

PURPOSE

The aim of this study was to investigate whether data obtained from the Lilium α-200 (Lilium Otsuka Co., Ltd., Japan) correlated with conventional frequency-volume chart (FVC) and post-void residual urine volume (PVR) obtained by urethral catheterization.

MATERIALS AND METHODS

This was a prospective multicentre study. Patients hospitalized for the treatment of lower urinary tract symptoms were included. Patients were evaluated with conventional FVC and Lilium α-200 for 2 days. PVR was measured by urethral catherization after urination at the end of the 2 day evaluation period.

RESULTS

A total of 42 patients were enrolled in this study. Voided volume and PVR measured by Lilium α-200 were significantly correlated with voided volume obtained from conventional FVC and PVR measured by urethral catheterization, respectively. There was considerable measurement error in voided volume measured by Lilium α-200 (-21.0±102.0 mL). In contrast, the error between PVR measured by the Lilium α-200 and PVR obtained by urethral catheterization was 2.4±52.0 mL. Additionally, high body mass index, but not sex, benign prostate hyperplasia, time zone of measurement (daytime vs. nighttime), and examiners (a urologist versus other healthcare providers) were significantly associated with inaccurate results in voided volume.

CONCLUSIONS

Voided volume and PVR measured by the Lilium α-200 were correlated with voided volume obtained from conventional FVC and PVR measured by urethral catheterization, although accuracy of the measurements was not high. The Lilium α-200 is a useful device to easily measure approximate bladder volume.

Comparative accuracy of the Lilium α-200 portable ultrasound bladder scanner and conventional transabdominal ultrasonography for postvoid residual urine volume measurement in association with the clinical factors involved in measurement errors

AIM

We examined the comparative accuracy of the portable ultrasound bladder scanner, Lilium α-200, and conventional ultrasonography (CUS) in bladder volume measurement. We also examined factors that could lead to measurement errors.

METHODS

Postvoid residual (PVR) volume was measured by Lilium α-200 and CUS with catheterized volume as a comparator in 224 consecutive men, of which 109 were also measured for the serially inflated bladder with saline. The measurement accuracy with respect to the actual volume was evaluated by calculating the error volume (EV), % error volume (%EV), and their absolute values. Absolute %EV of ≤20% was designated as nonerror. The measurement of prostate volume, abdominal thickness, and pelvimetry was performed on magnetic resonance images.

RESULTS

PVR volumes measured by CUS are better correlated with actual volumes (r = .779) than those of Lilium α-200 (r = .606). When the measurement accuracy was indicated by absolute values of EV and %EV, CUS provided a more accurate estimate (21 ± 21 ml, 60 ± 42%) than Lilium α-200 (32 ± 45 ml, 91 ± 142%). The frequency of error was significantly increased at lower bladder volumes. Overestimation was associated with larger prostate size for the Lilium α-200, while underestimation was associated with greater bladder flattening for both methods.

CONCLUSION

PVR volumes measured by Lilium α-200 were fairly correlated with actual volumes. However, their relative errors were too large to correctly predict the actual volume. Flattened bladder and a large prostate may hinder accurate measurements. Consequently, Lilium α-200 is not superior to CUS and its feasibility is limited to when the precise measurement is not required.