Novel algorithms for reducing bladder volume estimation error caused by scanning positions

2016 ◽  
Vol 94 (6) ◽  
pp. 1138-1154
Author(s):  
Kang Li ◽  
Quan Guo ◽  
Jixiang Guo
Keyword(s):  
Estimation Error ◽  
Volume Estimation ◽  
Bladder Volume ◽  
Novel Algorithms

Assessment of 2D ultrasound fluid volume estimation accuracy in different shaped objects: an in vitro study

2019 ◽  
Vol 61 (2) ◽  
pp. 253-259
Author(s):  
Iroshani Kodikara ◽  
Iroshini Abeysekara ◽  
Dhanusha Gamage ◽  
Isurani Ilayperuma
Keyword(s):  
Estimation Error ◽  
In Vitro Study ◽  
High Accuracy ◽  
Volume Estimation ◽  
Estimation Accuracy ◽  
Rater Agreement ◽  
Actual Volume ◽  
2D Ultrasound ◽  
One Way Anova

Background Volume estimation of organs using two-dimensional (2D) ultrasonography is frequently warranted. Considering the influence of estimated volume on patient management, maintenance of its high accuracy is empirical. However, data are scarce regarding the accuracy of estimated volume of non-globular shaped objects of different volumes. Purpose To evaluate the volume estimation accuracy of different shaped and sized objects using high-end 2D ultrasound scanners. Material and Methods Globular (n=5); non-globular elongated (n=5), and non-globular near-spherical shaped (n=4) hollow plastic objects were scanned to estimate the volumes; actual volumes were compared with estimated volumes. T-test and one-way ANOVA were used to compare means; P<0.05 was considered significant. Results The actual volumes of the objects were in the range of 10–445 mL; estimated volumes ranged from 6.4–425 mL ( P=0.067). The estimated volume was lower than the actual volume; such volume underestimation was marked for non-globular elongated objects. Regardless of the scanner, the highest volume estimation error was for non-globular elongated objects (<40%) followed by non-globular near-spherical shaped objects (<23.88%); the lowest was for globular objects (<3.6%). Irrespective of the shape or the volume of the object, volume estimation difference among the scanners was not significant: globular (F=0.430, P=0.66); non-globular elongated (F=3.69, P=0.064); and non-globular near-spherical (F=4.00, P=0.06). A good inter-rater agreement (R=0.99, P<0.001) and a good correlation between actual versus estimated volumes (R=0.98, P<0.001) were noted. Conclusion The 2D ultrasonography can be recommended for volume estimation purposes of different shaped and different sized objects, regardless the type of the high-end scanner used.

scholarly journals Simple calculation using anatomical features on pre-treatment verification CT for bladder volume estimation during radiation therapy for rectal cancer

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Nalee Kim ◽  
Hong In Yoon ◽  
Jin Sung Kim ◽  
Woong Sub Koom ◽  
Jee Suk Chang ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Cone Beam Ct ◽  
Ct Images ◽  
Volume Estimation ◽  
Bladder Volume ◽  
Cone Beam ◽  
Anatomical Features ◽  
Treatment Verification ◽  
Pre Treatment ◽  
Bladder Scanner

Abstract Background Despite detailed instruction for full bladder, patients are unable to maintain consistent bladder filling during a 5-week pelvic radiation therapy (RT) course. We investigated the best bladder volume estimation procedure for verifying consistent bladder volume. Methods We reviewed 462 patients who underwent pelvic RT. Biofeedback using a bladder scanner was conducted before simulation and during treatment. Exact bladder volume was calculated by bladder inner wall contour based on CT images (Vctsim). Bladder volume was estimated either by bladder scanner (Vscan) or anatomical features from the presacral promontory to the bladder base and dome in the sagittal plane of CT (Vratio). The feasibility of Vratio was validated using daily megavoltage or kV cone-beam CT before treatment. Results Mean Vctsim was 335.6 ± 147.5 cc. Despite a positive correlation between Vctsim and Vscan (R2 = 0.278) and between Vctsim and Vratio (R2 = 0.424), Vratio yielded more consistent results than Vscan, with a mean percentage error of 26.3 (SD 19.6, p < 0.001). The correlation between Vratio and Vctsim was stronger than that between Vscan and Vctsim (Z-score: − 7.782, p < 0.001). An accuracy of Vratio was consistent in megavoltage or kV cone-beam CT during treatment. In a representative case, we can dichotomize for clinical scenarios with or without bowel displacement, using a ratio of 0.8 resulting in significant changes in bowel volume exposed to low radiation doses. Conclusions Bladder volume estimation using personalized anatomical features based on pre-treatment verification CT images was useful and more accurate than physician-dependent bladder scanners. Trial registration Retrospectively registered.

Estimating Traffic Accident Rates While Accounting for Traffic-Volume Estimation Error: A Gibbs Sampling Approach

2000 ◽  
Vol 1717 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Gary A. Davis
Keyword(s):  
Gibbs Sampling ◽  
Traffic Accident ◽  
Estimation Error ◽  
Estimation Method ◽  
Volume Estimation ◽  
Accident Rate ◽  
Traffic Count ◽  
Accident Rates ◽  
A Site ◽  
Work Done

Traffic-accident rates that are estimated for individual roadway sites are often used to identify potentially hazardous locations. Occasionally they are used to test whether an accident countermeasure is associated with a statistically significant change in accident rate. In assessing the uncertainty attached to estimated accident rates, it is often implicitly assumed that the total traffic at a site is known with certainty, when in actuality the total traffic almost always must be estimated from a short sample of traffic counts. This introduces estimation error, which, if ignored, can lead one to overstate the accuracy of an accident-rate estimate. An explanation is provided about how Bayes estimates of accident rates, which explicitly account for total traffic estimation error, can be computed readily using a (relatively) new estimation method called “Gibbs sampling.” A model of how traffic-count samples are related to total traffic is incorporated from earlier work done by the author and his students. In tests conducted using accident counts and traffic data from 17 automatic traffic-recorder sites in Minnesota, it was found that, when using a 2-day traffic-count sample, the traditional method for estimating accidents rates understated the likely error of these estimates by 12 to 40 percent, depending on the site.

Application of XBeach to model a storm response on a sandy spit at the southern Baltic

2015 ◽  
Vol 44 (4) ◽  
Author(s):  
Natalia Bugajny ◽  
Kazimierz Furmańczyk ◽  
Joanna Dudzińska-Nowak
Keyword(s):  
Estimation Error ◽  
Model Performance ◽  
High Sensitivity ◽  
Volume Estimation ◽  
Beach Erosion ◽  
Morphological Data ◽  
Storm Event ◽  
Storm Events ◽  
Storm Response ◽  
Selected Effects

AbstractThe process-based XBeach model has been used to simulate changes in beach and dune morphology in terms of influence of the significant storm event on the sandy Dziwnow Spit, located in the western part of the Polish coast. The research was carried out as part of the SatBałtyk project and represents the first stage of XBeach model application to create a system for recording the selected effects and hazards caused by current and expected storm events. The significant storm event, registered in 2009, was used for model calibration. Ten cross-shore profiles were selected and compared against preand post-storm morphological data. Model performance was verified on the basis of BSS values for the terrestrial part of the profiles. Verification of the results was performed using two different approaches: on the basis of the highest mean BSS value for all profiles together and for one set of parameters (approach no. 1) and on the basis of the highest BSS value for each profile and most adequate sets of parameters (approach no. 2). Additionally, the observed and modelled beach and dune volume changes were calculated. The research showed that the XBeach model is well capable of simulating the dune and beach erosion caused by the storm event, but the model requires site-specific calibration. High sensitivity of the XBeach model to the facua parameter was determined; the parameter defines the wave shape and affects the sediment transport. The best fit of the profiles was obtained for BSS, ranging between 0.71 and 0.93, with the parameter hmin = 0.01 or 0.05, facua = 0.2-0.5, wetslp = 0.2-0.4 and dryslp = 1 or 1.5. The volume estimation error ranged from + 0.6 m

Sign in / Sign up

Export Citation Format

Share Document