Bladder Volume Measurement Research Articles

Intra- and inter-rater reliability of post-void residual bladder volume with ultrasound.

The purpose of the present study was to test the intra- and inter-rater reliability of the measurement of post-void residual bladder volume using ultrasound. Two evaluators performed three measurements of the height, width, and length of the empty bladder using ultrasound. The voiding residual volume was calculated using the equation: volume = length × width × height × 0.52. Intraclass correlations (ICC) were calculated considering: ICC ≥ 0.75 excellent, 0.40 ≤ ICC < 0.75 satisfactory, and ICC <0.40 poor, with a significance level of 5% and analysis of confidence intervals (95% CI). Twenty women participated, with an average age of 27.95 ± 3.15years. The inter-rater ICCs for height, width, and length were 0.96 (CI 0.89-0.98), 0.88 (CI 0.71-0.95), and 0.84 (CI0.60-0.94) respectively. For the intra-rater ICCs, the values were 0.97 (CI 0.95-0.99), 0.98 (CI 0.96-0.99), and 0.97 (CI 0.94-0.99) for evaluator 1 and 0.99 (CI 0.97-0.99), 0.97 (CI 0.94-0.99), and 0.95 (CI 0.90-0.98) for evaluator 2, for height, width, and length, respectively. The residual inter-test volume was 0.96 (CI 0.90-0.99) and the intra-test volume was 0.99 (CI 0.97-0.99). All analyses presented p < 0.0001. The intra- and inter-rater reliability for both the post-void residual volume and measurement of the bladder dimensions showed excellent agreement.

Validation of a real-time bladder sensation meter during oral hydration in healthy adults: Repeatability and effects of fill rate and ultrasound probe pressure.

A non-invasive protocol was previously developed using three-dimensional ultrasound and a sensation meter to characterize real-time bladder sensation. This study the protocol by measuring the effects of fill rateand ultrasound probe pressure during oral hydration. Healthy volunteers with no urinary symptoms (based on International Consultation on Incontinence Questionnaire on Overactive Bladder surveys) were recruited into an oral hydration study. Throughout two complete fill-void cycles, participants drank 2 L Gatorade G2 (The Gatorade Company, Inc., Chicago, Illinois) and used a touch-screen sensation meter to record real-time bladder sensation (0%-100%). The study was repeated three times, once per week (Visits A, B, and C). In Visits A and B, ultrasound was used to measure bladder volume every 5 minutes. Ultrasound was not used in Visit C except at 100% capacity. Volume data from Visit B were used to estimate volumes throughout the fills in Visit C. Sensation-capacity curves were generated for each fill for comparative analysis. Ten participants completed three visits (60 total fills). Increased fill rate led to decreased sensation throughout filling, andultrasound probe pressure led to increased sensation. Participants reported higher sensation at low volumes during Fill 1 of Visit A before training with the sensation meter. Sensation curves with intermittent ultrasound showed repeatability for Fill 2 in Visits A and B. Fill rate and ultrasound probe pressure affect real-time bladder sensation during oral hydration. This study demonstrated repeatability of real-time bladder sensation during a two-fill oral hydration protocol with ultrasound.

Validity of bladder volume measurement by ultrasound in women postpartum.

Vaginal birth increases the risk of urinary retention and overdistention of the bladder. To avoid unnecessary discomfort by catheterization, it is preferable to use ultrasound for diagnosis of these conditions. The aim of this study was to determine the validity of transabdominal ultrasound and a portable ultrasound system, Biocon-700, to measure bladder volume in women postpartum. Fifty women were included in this method comparison study. Within 48h of giving birth, their bladder volume was measured in randomized order with both transabdominal ultrasound and Biocon-700. After urination, participants were scanned with Biocon-700 to measure residual bladder volume, and finally the bladder was emptied by catheterization. The total bladder volume was calculated as the voided volume plus the catheterized volume. Biocon-700 measured 43.4ml ± 117.4ml (mean ± SD) lower than the total bladder volume, while volumes measured by transabdominal ultrasound were 117.8ml ± 110.0ml (mean ± SD) lower. Linear regression showed significant proportional bias in both methods. The Biocon-700 could detect a residual bladder volume > 150ml with a positive predictive value of 66.7% and a negative predictive value of 100%. Neither transabdominal ultrasound nor the portable ultrasound system, Biocon-700, can be used to measure bladder volume precisely after vaginal delivery. However, both ultrasound methods can be used as screening tools to prevent overdistention of the bladder, and Biocon-700 can furthermore be used to screen women for a residual bladder volume > 150ml.

Study on the significance of consistency of preoperative and postoperative bladder filling in patients with cervical cancer for target area and organ at risk in IMRT

Objective Bladder filling in patients with cervical cancer before and after operation during intensity-modulated radiotherapy (IMRT) was controlled by using bladder volume measurement instrument (BVI 9400). The displacement errors of the target area and the changes of the irradiation dose and the morphology of the filling bladder were compared. The significance of consistency of preoperative and postoperative bladder filling in IMRT for cervical cancer was investigated. Methods Forty-five patients with cervical cancer treated with radiotherapy in our hospital in 2018 were recruited and divided into A, B and C groups (n=15). In group A, patients did not undergo surgery, patients in group B received radical resection of cervical cancer (bladder volume measurement (BVI 9400) was utilized to monitor the bladder urine volume in both A and B groups before treatment). In group C, patients who self-controlled urination without monitoring bladder urine volume before treatment were randomly selected. All patients in three groups underwent KV-CBCT scan before treatment for online registration analysis. The displacement errors in the x-(left and right), y-(head and foot), z-axis directions (ventral and dorsal), PTV coverage volume percentage(V100) and percentage difference (ΔV100) of the prescription dose were calculated. Results The average displacement errors in the x-, y-, z-axis directions were as follows: 1.67 mm, 1.55 mm and 1.67 mm in group A, 1.43 mm, 1.58 mm and 1.84 mm in group B, and 2.27 mm, 2.30 mm and 2.08 mm in group C, respectively. In group A, the V100 was calculated as 96.96% and ΔV100 was 1.17%. In group B, V100 was 95.9% and ΔV100 was 1.29%. In group C, V100 was 94.02% and ΔV100 was 2.17%. Conclusions Controlling the consistency of bladder filling can reduce the effect of inconsistency of bladder filling upon the displacement errors to certain extent, which can guarantee the accuracy of the target location and the irradiation dose of the target, protect the bladder, small intestine and rectum, and alleviate the radiation-induced response of cervical cancer patients. Key words: Bladder filling status; Planning target volume; Cervical neoplasm/intensity-modulated radiotherapy

Ultrasonographic Assessment of Bladder Volumes in Children Undergoing Penile Surgery: Does the Type of Anesthesia Matter?

There are scant data reporting postoperative ultrasonographically measured bladder volumes in children undergoing penile surgery. We studied the effect of various anesthesia techniques on return of micturition after penile surgery in children, using ultrasonographically measured bladder volumes. Ultrasonographically measured postvoiding residual bladder volumes indexed to age-appropriate capacity, and time elapsed between the end of surgery and spontaneous voiding after pediatric circumcision, distal hypospadias repair, or repair of urethrocutaneous fistula, were studied. Children between 4 months and 12 years were randomized to caudal block, intravenous (IV) fentanyl or penile block, in association with inhaled general anesthesia. Bladder volumes were measured before surgery and immediately after voiding for the first time. Time to first postsurgery void was also recorded. Thirty-one children completed all assessments; 12 underwent caudal block, 9 IV fentanyl anesthesia, and 7 were given penile block. The mean first postvoid bladder residual volumes were highest in the caudal and lowest in the penile block children (27.5 vs. 17.3 mL, P = 0.003). The time elapsing between the end of surgery and first voiding was the longest in the fentanyl group compared with caudal and penile blocks (232, 178, 150 minutes, respectively, P = 0.02). None of the anesthetic techniques provoked postoperative urinary retention after minor penile surgery in children. The penile block appears superior to caudal block or to IV fentanyl-based anesthesia with regard to postoperative recovery of normal micturition.

Point-of-care ultrasound before attempting clean-catch urine collection in infants: a randomized controlled trial.

A new non-invasive bladder stimulation technique has been described to obtain clean-catch urine specimens in infants. This study aimed to evaluate if point-of-care ultrasound (POCUS) guided feeding protocol to measure bladder volume prior to stimulation techniques improves clean-catch urine collection success. A prospective randomized controlled trial study was conducted in a tertiary care pediatric emergency department. Infants aged less than 6 months needing a urine sample were randomized to either POCUS group or feeding group (standard procedure) before performing a standardized clean-catch urine stimulation technique. In the POCUS group, a feeding period was permitted if the bladder width was less than 2 cm, otherwise the clean-catch urine was performed immediately. The primary outcome was the success of the procedure defined by the collection of at least 2 mL of urine, obtained within 300 seconds of bladder stimulation manoeuvres. It was estimated that the recruitment of 200 children was necessary to yield 80% power to identify an improvement of 20% in the success rate. A total of 201 infants were included. The procedure was not more successful in the POCUS group (48%) compared to the feeding group (54%) (Difference: 6.5%; 95% CI: -7.3 to 19.8%). The mean time to collect urine samples from randomization to sample collection was not different between the two groups. Our study failed to show a benefit of using POCUS to improve the success rate of stimulated clean-catch urine. Moreover, the importance of the feeding period prior to clean-catch urine manoeuvres should be evaluated further. NCT02751671.

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

This study examined the accuracy of a new portable ultrasound bladder scanner, the Lilium α-200 (Lilium Otsuka, Kanagawa, Japan), by evaluating the correlation between bladder volumes periodically measured by the Lilium α-200 and instilled volume during video-urodynamic studies (V-UDS). Using the Lilium α-200, fluid volume was measured prospectively in the bladders of patients with lower urinary tract dysfunction during V-UDS. This was done both immediately after micturition (for assessment of post-void residual [PVR] volume) and at 1-minute intervals during filling cystometry with patients in the supine position. These measurements were then compared with the PVR volume obtained directly by catheter drainage and instilled volume during cystometry using paired t tests and Spearman's rank correlation. Fifteen male patients (median age 70.5 years; range 18-84 years) were included in the study. The PVR volume measured by the Lilium α-200 was strongly correlated with that obtained by catheter drainage (r = 0.94; P < 0.0001). There was a strong correlation between instilled and bladder volumes measured by the Lilium α-200 at every minute during and at the end of instillation (281 measurements in 15 patients; r = 0.86; P < 0.0001). However, the relative error of bladder volumes measured by the Lilium α-200 during cystometry showed considerable variation (mean [± SD] 5.6 ± 62.9%). Bladder volumes measured periodically by the Lilium α-200 during cystometry were strongly correlated with actual PVR or instilled volumes. However, they showed considerable variation and may not predict actual volume accurately. The Lilium α-200 is feasible for obtaining an approximate measure of bladder volume.

Effect of Premicturitional Bladder Volume on the Accuracy of Sonographic Assessment of Post Void Residual Urine Volume Measurement by Transabdominal Ultrasonography

Introduction: The Post Void Residual Urine volume (PVRU) is frequently significant in patients with bladder outflow obstruction; especially in patients with enlarged prostate and prostatism. The PVRU forms an important part of radiological investigation. Accurate measurement of the residual urine volume changes observed serially over a period of time may indicate clinical progress. The purpose of this study was to evaluate the effect of pre-void bladder volume on PVRU measurements.&#x0D; Methods: A prospective study was conducted to determine the accuracy of PVRU measurement in patient presenting with lower urinary tract symptoms (LUTS). 50 patients with LUTS were assessed ultrasonographically for pre void and post void bladder volumes during the study period of March 2017 till August 2017. PVRU measurements done in patients with bladder filling sensation at moderate to full capacity resulted in high estimations of PVRU which was quite significant in this study.&#x0D; Results: There was significant difference in the estimated PVRU between patients having high initial premicturitional volume (546±144 ml) than those with lower or moderate filling volume (261±58 ml) with mean of 173 ml and 35 ml respectively. The difference in estimated PVRU was highly significant with p value of &lt; 0.0001.&#x0D; Conclusions: Measurement of pre void urinary bladder volume with an uncomfortably full bladder results in high post micturitional (PMRU) values even in most patients without lower urinary tract symptoms which may be false-positive. We advise that initial or pre-void urine volume be measured when the patient has initial or moderate feeling of bladder fullness.

Effects of bladder shape on accuracy of measurement of bladder volume using portable ultrasound scanner and development of correction method.

To compare the accuracy of using a bladder scanner to measure bladder volume through intermittent catheterization (IC) in patients and to introduce the Bladder Deformation Index (BDI) to develop a correction method. Bladder volume was assessed by a nurse with the scanner. A second nurse catheterized the patient's bladder. A third nurse measured the urine volume in a 500-mL or 1000-mL graduated cylinder. Sixty one patients were included and 590 pairs of data were obtained. The mean bladder volume measured using a scanner and IC was (332.3 ± 156.1) mL and (339.1 ± 158.8) mL. The mean absolute difference was 30.8 mL. The correlation coefficient was 0.929. Patients were classified into 2 groups depending on whether they had undergone augmentation cystoplasty. The mean absolute difference was 109.2 and 20.4 mL. The correlation coefficient was 0.712 and 0.981. According to the BDI, bladders can be classified into 3 groups. The mean absolute difference was 21.9, 60.4, and 109.4 mL. The correlation coefficient was 0.970, 0.839, and 0.783. The linear regression equations of Grade I and Grade II were Y = 1.11X + 3.1 and Y = 0.76X + 161.5. The results showed that bladder shape plays a critical role in accuracy which is inversely associated with BDI. This degree of accuracy is sufficient; especially measurement adjusted using the linear regression equation in patients with high BDI. However, although the preliminary results of the study are promising, a large-scale prospective study should be needed to address the validation of the data in the future.

Evaluation of electrical impedance tomography for determination of urinary bladder volume: comparison with standard ultrasound methods in healthy volunteers

BackgroundContinuous non-invasive urinary bladder volume measurement (cystovolumetry) would allow better management of urinary tract disease. Electrical impedance tomography (EIT) represents a promising method to overcome the limitations of non-continuous ultrasound measurements. The aim of this study was to compare the measurement accuracy of EIT to standard ultrasound in healthy volunteers.MethodsFor EIT of the bladder a commercial device (Goe MF II) was used with 4 different configurations of 16 standard ECG electrodes attached to the lower abdomen of healthy participants. To estimate maximum bladder capacity (BCmax) and residual urine (RU) two ultrasound methods (US-Ellipsoid and US-L × W × H) and a bedside bladder scanner (BS), were performed at the point of urgency and after voiding. For volume reference, BCmax and RU were validated by urine collection in a weight measuring pitcher. The global impedance method was used offline to estimate BCmax and RU from EIT.ResultsThe mean error of US-Ellipsoid (37 ± 17%) and US-L × W × H (36 ± 15%) and EIT (32 ± 18%) showed no significant differences in the estimation of BCmax (mean 743 ± 200 ml) normalized to pitcher volumetry. BS showed significantly worse accuracy (55 ± 9%). Volumetry of RU (mean 152.1 ± 64 ml) revealed comparable higher errors for both EIT (72 ± 58%) and BS (63 ± 24%) compared to US-Ellipsoid (54 ± 25%). In case of RU, EIT accuracy is dependent on electrode configuration, as the Stripes (41 ± 25%) and Matrix (38 ± 27%) configurations revealed significantly superior accuracy to the 1 × 16 (116 ± 62%) configuration.ConclusionsEIT-cystovolumetry compares well with ultrasound techniques. For estimation of RU, the selection of the EIT electrode configuration is important. Also, the development of an algorithm should consider the impact of movement artefacts. Finally, the accuracy of non-invasive ultrasound accepted as gold standard of cystovolumetry should be reconsidered.

Non-invasive bladder volume measurement for the prevention of postoperative urinary retention: validation of two ultrasound devices in a clinical setting

Ultrasound scanning of bladder volume is used for prevention of postoperative urinary retention (POUR). Accurate assessment of bladder volume is needed to allow clinical decision-making regarding the need for postoperative catheterization. Two commonly used ultrasound devices, the BladderScan® BVI 9400 and the newly released Prime® (Verathon Medical®, Bothell, WA, USA), with or without the ‘pre-scan’ option, have not been validated in clinical practice. The aim of this study was to assess the performance of these devices in daily clinical practice. Between June and September 2016 a prospective observational study was conducted in 318 surgical patients (18 years or older) who needed a urinary catheter perioperatively for clinical reasons. For acceptable performance, we required that the volume as estimated by the BladderScan® differs by no more than 5% from the actual urine volume after catheterization. The Schuirmann’s two one-sided test was performed to assess equivalence between the BladderScan® estimate and catheterization. The BVI 9400® overestimated the actual bladder volume by + 17.5% (95% CI + 8.8 to + 26.3%). The Prime® without pre-scan underestimated by − 4.1% (95% CI − 8.8 to + 0.5%) and the Prime® with pre-scan underestimated by − 6.3% (95% CI − 11.6 to − 1.1%). This study shows that while both ultrasound devices were able to approximate current bladder volume, both BVI 9400® and Prime®—with and without pre-scan—were not able to measure the actual bladder volume within our predefined limit of ± 5%. Using the pre-scan feature of the Prime® did not further improve accuracy.

Bladder filling during radiation therapy for prostate cancer treatment: Assessment via bladder ultrasound scanner.

147 Background: Prostate cancer patients treated with external beam radiation therapy are instructed to present daily with a full bladder to decrease small bowel and bladder toxicity and to increase reproducibility of treatment. However, older patients may have difficulty presenting with full bladders and variation of bladder volume with treatment is unknown. The objective of this study was to assess bladder filling at the time of radiation treatment (RT) using a bladder ultrasound in patients undergoing treatment for prostate cancer. Methods: Patients with prostate cancer were prospectively enrolled prior to CT simulation from January to August 2017. Bladder volume was recorded during CT simulation and daily immediately prior to RT. Patients were instructed to drink 8-12 ounces of water 30-60 minutes prior to RT. Three bladder volume measurements were recorded daily and averaged at the time of each treatment. Average bladder volume during treatment and the number of treatments with low bladder volumes ( &lt; 50cc, &lt; 60cc, and &lt; 100cc) were reported using descriptive statistics. Results: A total of 13 patients completed a median of 42 days of RT during the study period, resulting in 550 daily bladder volumes. Ten patients were treated definitively and 3 with salvage radiation after prostatectomy. The median age of patients in the study was 72 years. Older patients were statistically more likely to present with low bladder volumes, with percentage of treatments with a bladder volume less than 50cc, 60cc, and 100cc being 29%, 42%, and 66% compared to only 4%, 7%, and 18% in patients aged &lt; 70 (P &lt; 0.01). The average bladder volume at the time of CT simulation was 176cc ± 57cc and the average volume during treatment was 140cc± 93cc, which was not statistically different (P = 0.28). The bladder volume did not significantly change over the course of treatment. Conclusions: Older patients (age 70+) with prostate cancer were more likely to present for RT with low bladder volumes in this prospective study. Our findings suggest that older patients should receive extra counseling about bladder filling and/or may require less bladder filling at the time of CT simulation to provide more accurate bowel dosimetry measurements.

Comparison of 2D and 3D ultrasound methods to measure serial bladder volumes during filling: Steps toward development of non-invasive ultrasound urodynamics

OBJECTIVESNon-invasive methods to objectively characterize overactive bladder (OAB) and other forms of voiding dysfunction using real-time ultrasound are currently under development but require accurate and precise serial measurements of bladder volumes during filling. This study’s objective was to determine the most accurate and precise ultrasound-based method of quantifying serial bladder volumes during urodynamics (UD).METHODSTwelve female participants with OAB completed an extended UD procedure with the addition of serial bladder ultrasound images captured once per minute. Bladder volume was measured using three ultrasound methods: (1) Vspheroid: two-dimensional (2D) method calculated assuming spheroid geometry; (2) Vbih: 2D correction method obtained by multiplying Vspheroid by a previously derived correction factor of 1.375; and (3) V3D: three-dimensional (3D) method obtained by manually tracing the bladder outline in six planes automatically reconstructed into a solid rendered volume. These volumes were compared to a control (Vcontrol) obtained by adding UD infused volume and the volume of estimated urine production.RESULTSBased on linear regression analysis, both Vbih and V3D were fairly accurate estimators of Vcontrol, but V3D was more precise. Vspheroid significantly underestimated Vcontrol.CONCLUSIONSAlthough the Vbih and V3D methods were more accurate than the more-commonly used Vspheroid method for measuring bladder volumes during UD, the V3D method was the most precise and could best account for non-uniform bladder geometries. Therefore, the V3D method may represent the best tool required for the continued development of non-invasive methods to diagnose OAB and other forms of voiding dysfunction.

Treatment Planning Volume According to Change in Bladder Volume in Therapy of Proton Beam in Magnetic Field

The purpose of this study was to investigate the changes of bladder volume before therapy of proton beam in magnetic field, and to estimate the target volume (PTV) margin to be considered in treatment planning. Thirty patients with prostate cancer were included in this study. Three gold fiducial markers were attached to the prostate to confirm the position of the prostate by pretreatment X-ray. The urine was completely emptied 1 hour and 30 minutes before the CT-Simulation, and the urine was confirmed by ultrasonography. The bladder was filled with 500 cc of water. Bladder volume was measured by CT scans after treatment. On the first day of treatment, 30 patients underwent the same pretreatment as in CT-Simulation, and their bladder volume was obtained using ultrasound during the 25th treatment, and compared with the treatment plan. We also investigated daytime volatility during the treatment period. The mean bladder volume ultrasonography mean (BV<SUB>USmean</SUB>) was found to be 302 ± 89 ml (range: 168 ± 166 ml) −553 ml). BV<SUB>USmean</SUB> was 84 % of BV<SUB>CTmean</SUB>. Ultrasound- measured bladder volume was smaller than that measured by CT. The correlation coefficient between BVUSmean and BVCTmean was 0.187 (p = 0.322). Bland-Altman analysis showed that the BV<SUB>CTmean</SUB> and BV<SUB>USmean</SUB> agreement ranged from −202.17 to 315.83, with an average value of 70. The mean (bias, bias) and standard deviation (precision) of the differences between the two measurements was 56.83 ± 132.14 ml. BV<SUB>CTmean</SUB> and BV<SUB>USmean</SUB> showed a large range of change. BV<SUB>USWeekly1-5</SUB>, which was measured Weeklyly, showed a certain decrease with the treatment time, as compared with BV<SUB>CTmean</SUB>. In conclusion, large changes and differences in bladder volume should always be treated with ultrasound before treatment, and the range of rectal area should coincide. Therefore, excessive radiography is unnecessary.

A Urinary Bladder Volume Measurement Circuit Using a Simplified Very Small Phase Difference Measurement Circuit

SUMMARYIn order to implement the measurement and the evaluation of analog signals in high accuracy, to detect not only amplitude level but also phase information is necessary. For example, measurement of very small phase difference is desired in fields such as electric power and organism‐related. Particularly, in organism‐related field, impedance measurement is important and it is used to measure the urinary bladder volume, the respiratory volume, and so on. For these purposes, portable and real‐time measurement devices with small sized is suitable. In this paper, we propose the urinary bladder volume measurement circuit using a simplified very small phase difference measurement circuit. This circuit is able to infer the changes of urinary bladder volume by measuring bioimpedance and phase difference of urinary bladder noninvasively with four‐terminal method.

Positional uncertainty of vaginal cuff and feasibility of implementing portable bladder scanner in postoperative cervical cancer patients

PurposeTo propose a geometrical margin for definition of the vaginal cuff PTV using only CT images of the full bladder (CTfull) in postoperative cervical cancer patients. MethodsTwenty-nine operated cervical cancer patients underwent volumetric arc therapy with a bladder filling protocol. This study assessed bladder filling using a portable bladder scanner and cone-beam computed tomography (CBCT) during the entire treatment period. The measured bladder volumes with a BladderScan® were compared with the delineated volume on CBCT. Titanium clips in the vaginal cuff were analysed to assess geometrical uncertainty and the influence of rectal and bladder volume changes. ResultsBladderScan® showed good agreement with the delineated volume (R = 0.80). The volume changes in the bladder have a greater influence on the clip displacements than in the rectum. The 95th percentile of uncertainty of the clips in reference to CTfull in the right-left (RL), the superoinferior (SI), and the anteroposterior (AP) was 0.32, 0.65, and 1.15 cm, respectively. From this result and intra-fractional movements of the vaginal cuff reported by Haripotepornkul, a new geometrical margin was proposed for definition of the vaginal cuff planning target volume (PTV): 0.5, 0.9, and 1.4 cm in the RL, SI, and AP directions, respectively. ConclusionsA new geometrical margin was proposed for definition of the vaginal cuff PTV based on CTfull, which will be needless of empty bladder at the planning CT scan. This method allows patients to reduce the burden and efficient routine CT scans can be improved.

Discrepancies in measuring bladder volumes with bedside ultrasound and bladder scanning in the intensive care unit: A pilot study.

Intensive care unit patients are at risk for catheter-associated urinary tract infection. Earlier removal of catheters may be possible with accurate measurement of bladder volume. The purpose was to compare measured bladder volumes with bedside ultrasound, bladder scanner, and urine volume. Prospective correlational descriptive study. Surgical/trauma intensive care unit and medical intensive care unit. Renal dialysis patients with less than 100 ml of urine in 24 h prior to urinary catheter removal and patients with suspected catheter obstruction. A physician trained in ultrasound and an advanced practice registered nurse trained in bladder scanning measured bladder volume; each blinded to the other's measurement. Device used first (ultrasound or bladder scanner) alternated daily. The intensive care unit team determined need for intermittent catheterization or treatment for suspected obstruction. Fifty-one measurements from 13 patients were obtained with results reported in milliliters. Ultrasound measurements were a mean volume of 72.1 ± 127 (range: 1.7-666) and the bladder scanner measurements were 117 ± 131 (0-529). On six occasions in five dialysis patients, urine volume measurement was available. The mean difference in ultrasound-urine volume mean difference was 0.5 ± 37.8 (range: -68 to 38.2) and the bladder scanner-urine volume was 132 ± 167 (-72 to 397). Two patients with suspected catheter obstructions had ultrasound, bladder scanner, urine volume measurements, respectively: (1) 539, 51, >300 (began voiding before catheter replaced); (2) 666, 68, 1000 with catheter replacement. Conditions leading to greatest differences were obesity, indwelling catheter and ascites. These results demonstrate the inaccuracy of the bladder scanner. Ultrasound measurements appear more accurate. To remove urinary catheters in patients with minimal to low urine output, serial ultrasound measurements can be used to monitor bladder volumes and return of renal function.

EP12.37: The value of 2D and 3D bladder volume measurement in the prediction of spontaneous resolution of prenatal hydronephrosis

To assess whether fetal bladder volume can be used in the prediction of spontaneous resolution of prenatal hydronephrosis (PNH) and to determine the feasibility of measuring bladder volume using three-dimensional (3D) ultrasound, in comparison with two-dimensional (2D) bladder measurement. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic accuracy of 2D bladder volume in predicting prognosis in PNH. Virtual organ computer-aided analysis (VOCAL) was performed to calculate 3D bladder volume for cases where 3D measurements were available and then 2D and 3D bladder volume measurement agreement was determined using a paired t-test and difference against the mean plots. ROC analysis showed that 2D bladder volume could not predict the spontaneous resolution of PNH for the 42 cases included. Gestational age, at first diagnosis of PNH, could predict prenatal resolution; area under the ROC curve (AUC) = 0.83 (95% confidence interval (CI) 0.70 - 0.95) and postnatal resolution within the first few weeks of birth; AUC = 0.76 (95% CI 0.61 - 0.91). There was a correlation between gestational age and bladder volume, with a 25% increase in bladder volume for each week gestation (95% CI 21- 30%). 2D and 3D bladder volume measurements showed acceptable agreement in the 17 cases included. 2D Bladder volume measurement agrees with 3D measured using VOCAL software and is unable to predict the spontaneous resolution of PNH. Interestingly, PNH diagnosed at earlier gestational age resolved prenatally or by the first weeks of life, questioning the need for multiple prenatal scans which increase parental anxiety and use limited medical resources. Further research to validate these results and reduce the limitations of this retrospective pilot study is warranted.

Bladder filling variation during conformal radiotherapy for rectal cancer

Conformal radiotherapy for rectal cancer is associated with small bowel toxicity mainly diarrhea. Treating patients with a full bladder is one of the practical solutions to reduce small bowel toxicity. Previous studies on prostate and cervix cancer patients revealed that maintaining consistent bladder volume throughout radiotherapy treatment is challenging. The aim of this study was to measure bladder volume variation throughout radiotherapy treatment. This study also measured the association between bladder volume changes and diarrhea. Twenty two rectal cancer patients were recruited prospectively. Patients were planned for treatment with full bladder following departmental bladder filling protocol and the planning bladder volume was measured during CT-simulation. During radiotherapy, the bladder volume was measured weekly using cone-beam computed tomography (CBCT) and compared to planning bladder volume. Incidence and severity of diarrhea were recorded during the weekly patient review. There was a negative time trend for bladder volume throughout five weeks treatment. The mean bladder volume decreased 18 % from 123 mL (SD 54 mL) during CT-simulation to 101 mL (SD 71 mL) on the 5th week of radiotherapy, but the decrease is not statistically significant. However, there was a large variation of bladder volume within each patient during treatment. This study showed an association between changes of bladder volume and diarrhea (P = 0.045). In conclusion bladder volume reduced throughout radiotherapy treatment for conformal radiotherapy for rectal cancer and there was a large variation of bladder volume within patients.

Comparison of the validity of bladder volume measurement by four different kinds of ultrasound devices

Comparison of the validity of bladder volume measurement by four different kinds of ultrasound devices