Dataset Information

Evaluation of an ultrasound bladder scanner in supine and standing position.

ABSTRACT:

Purpose

This study examined the performance of a bladder volume measuring device, the BladderScan (BS) BVI9400. The use of the BS offers the possibility of assessing the bladder volume before positioning the patient and performing the daily image-guided radiotherapy procedure. Patients often cannot lie down before entering the treatment vault. Therefore, the BS was also assessed in a standing position.

Methods

The repeatability precision was first evaluated, which is the variability of immediate repeated measures of the BS with same operator and subject. This was followed by the reproducibility precision of the BS in which the operator and subjects differ. Finally, the trueness was evaluated in terms of fixed and proportional bias of the results by applying weighted least-squares fitting. Note that 53 and 85 patient measurements were carried out in supine and standing position, respectively, each consisting of three repeated BS measurements. These were compared with the computed tomography (CT)-delineated bladder volume.

Results

Repeatability was dependent on measurement value (heteroscedasticity) with σ_{repeatability} (BS) = ±15 cm³ ± 10%. However, the total agreement between BS and CT was low with the 95% limits of agreement (LOAs) exceeding ±200 cm³ due to poor patient reproducibility and presence of fixed and proportional bias. Only in the best case of male patients in the supine position, three BS measurements, and correction for the fixed and proportional bias, 95% LOAs of [-147, +114] cm³ were obtained between CT and BS.

Conclusion

The agreement of the BVI9400 BS with CT was found to be too low for radiotherapy applications.

SUBMITTER: Crop F

PROVIDER: S-EPMC8664133 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:IntroductionUltrasound guidance for percutaneous nephrolithotomy (PCNL) has gained acceptance amongst urologists given its numerous advantages over fluoroscopy. While traditionally performed in the prone position, this video demonstrates a step-by-step approach to performing PCNL in the supine position, solely under ultrasound guidance.Materials and methodsOnce in the modified supine (Galdakao-modified Valdivia) position, important anatomic landmarks are identified. It is important to first orient the ultrasound probe such that its cranial side corresponds to the left of the ultrasound screen. After optimizing a target calyx, keeping the needle in the imaging plane of the probe facilitates renal access. Tract dilation under ultrasound guidance is then achieved by keeping the wire and dilators in the same imaging plane.ResultsThe 11th and 12th ribs, paraspinous muscle, iliac crest, midaxillary line, and costal margin are the anatomic landmarks that orient the probe to the location of the kidney. Placing the ultrasound probe in the midaxillary line, parallel to the 11th rib allows the operator to identify key renal landmarks: the renal cortex, peri-pelvic fat, collecting system, kidney stone with its associated postacoustic shadow, and the intended target calyx. Controlling the needle is easiest in the longitudinal view, as the needle can be visualized from skin to target. Dilation under ultrasound relies on keeping the wire in view. The tip of the 10-French dilator is based on the location where the wire image disappears as the dilator advances. The balloon dilator tip is visualized on ultrasound reaching the appropriate depth just inside the collecting system, at which time balloon inflation results in complete dilation of the tract.ConclusionsThis video provides a step-by-step approach demonstrating that PCNL can be performed in the supine position using only ultrasound-guidance. This approach facilitates renal access in this position and obviates the need for radiation exposure.