Online MR evaluation of inter- and intra-fraction uterus motions and bladder volume changes during cervical cancer external beam radiotherapy

Purpose/objective(s) The purpose of the study was to assess the uterus motions and bladder volume changes of fractional movements in cervical sites throughout the external beam radiotherapy (EBRT) treatment. Materials/methods A prospective online MR imaging tracking study was conducted in EBRT 43 patients with at least 4 scans during each treatment (before: ultrasound scan, MRI scan, CBCT scan, after: MRI scan) were included. In order to improve the treatment repeatability, each patient was instructed to empty the bladder and drink 500 ml water 1 h before CT simulation and each treatment. If the ultrasound scan result reached the CT simulation volume of bladder, the treatment began. Bladder was outlined on the T2 weighted axial sequence and CBCT image by the two observers to avoid the influence of contouring. The data of bladder volume and scanning time were accurately recorded. The bladder volumes, filling rates and uterus motion were retrospectively analyzed by MIM software. Results Inter-fraction variation of the bladder volume was significant (p < 0.0001). Intra-fraction mean increase of the bladder volume was modest (30 cc) but significant (p < 0.001). Both inter- and intra-fraction of the uterus motion were significant. The average time between the pre-and post-fraction MRI scans was 27.82 ± 7.12 min (range 10–55 min) for IMRT plans and 24.14 ± 5.86 min (range7-38 min) for VMAT plan. Average bladder filling rate was 3.43 ml/min. The bladder filling rate did not change significantly with the course of treatment, but the bladder was more intolerant. Conclusion This is the most detailed assessment of intra-fraction and inter-fraction motion during EBRT for cervical cancer. Finally, this study will inform appropriate treatment margins for online adaptive radiotherapy. We suggest that at least one image scan is needed before the EBRT. The portable US scanner provides a quick but unreliable measurement of the bladder volume. There is a significant statistical difference between the results of ultrasonic scanning and that of image scanning.

A study of bladder filling consistency before and during the radiotherapy for pelvic cancer

The full text of this preprint has been withdrawn by the authors because preprints are not widely accepted in China. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

Psychological stress induced bladder overactivity in female mice is associated with enhanced afferent nerve activity

Psychological stress has been linked to the development and exacerbation of overactive bladder symptoms, as well as afferent sensitisation in other organ systems. Therefore, we aimed to investigate the effects of water avoidance stress on bladder afferent nerve activity in response to bladder filling and pharmaceutical stimulation with carbachol and ATP in mice. Adult female C57BL/6J mice were exposed to either water avoidance stress (WAS) for 1 h/day for 10 days or normal housing conditions. Voiding behaviour was measured before starting and 24-h after final stress exposure and then animals were euthanised to measure afferent nerve activity in association with bladder compliance, spontaneous phasic activity, contractile responses, as well as release of urothelial mediators. WAS caused increased urinary frequency without affecting urine production. The afferent nerve activity at low bladder pressures (4–7 mmHg), relevant to normal physiological filling, was significantly increased after stress. Both low and high threshold nerves demonstrated enhanced activity at physiological bladder pressures. Urothelial ATP and acetylcholine release and bladder compliance were unaffected by stress as was the detrusor response to ATP (1 mM) and carbachol (1 µM). WAS caused enhanced activity of individual afferent nerve fibres in response bladder distension. The enhanced activity was seen in both low and high threshold nerves suggesting that stressed animals may experience enhanced bladder filling sensations at lower bladder volumes as well as increased pain sensations, both potentially contributing to the increased urinary frequency seen after stress.

Monitoring bladder filling in patients with neurogenic urination disorders: the role of wearable hardware and software systems

Introduction. The use of wearable hardware and software systems to control bladder filling is considered one of the most important technologies for remote monitoring in patients with neurogenic urinary disorders. Materials and methods. A search, analysis and systematization of literature was carried out in the PubMed, e-library and Google Scholar databases using the keywords neurogenic urination disorders , neurogenic bladder , ultrasound diagnostics , ultrasound examination , monitoring , monitoring – total 211 sources, from which 46 were selected for writing the article. Theses and their abstracts, as well as conference abstracts were excluded from the analysis. Results. Ultrasound monitoring and bioimpedansometry, or a combination of both, allows for a non-invasive assessment of bladder volume, and the use of modern technologies, such as wireless communications and smartphone applications, allows the patient to maximize the individualization of the bladder emptying rhythm. Complicating moments in the use of these technologies are the conservatism of doctors, patient compliance, the lack of methodological developments and recommendations for the use of these monitoring technologies. Discussion. The monitoring of bladder filling allows to avoid unnecessary catheterizations reducing the risk of urinary tract infections. Also it allows forming a wake-up reflex in a child with enuresis when he or she feels an urge to urinate. These technologies are currently considered experimental. Additional research is required before introducing them into clinical practice. Conclusions. The use of wearable hardware and software systems for monitoring bladder filling and special applications in smartphones in patients with neurogenic urinary disorders is an important step in finding solutions for each individual patient. Clinical monitoring studies are needed in routine urological practice.