Ultrasonography of the Urinary Bladder

Incidence of urinary retention and relations between patient's complaint, physical examination, and bladder ultrasound

OBJECTIVE

To describe the frequency of urinary complaints, bladder globe, and need for bladder relief catheterization according to ultrasound; to investigate the relationship between the urinary volume estimated by ultrasound and the one drained in catheterization; and to describe the relationship of patient's complaints and detection of bladder globe with the diagnosis of urinary retention.

METHOD

A cross-sectional study with clinical patients with suspected urinary retention in a tertiary hospital, conducted from February to September 2018. Urinary volume ≥500 mL in ultrasound was considered urinary retention.

RESULTS

Two hundred and five evaluations were performed in 44 patients. Urinary retention was detected by ultrasound in 33.2% of the evaluations. There was a strong correlation between ultrasound and bladder catheterization. There was a higher frequency of identification of bladder globe in urinary volumes ≥300 mL.

CONCLUSION

The incidence of urinary retention was higher when ultrasound was used for the diagnosis, when compared to patient's complaint and physical examination. Ultrasound showed to be accurate in establishing urinary volume.

A non-invasive ultrasound imaging method to measure acute radiation-induced bladder wall thickening in rats

Background

Methods for the non-invasive quantification of changes in bladder wall thickness as potential predictors of radiation cystitis in pre-clinical research would be desirable. The use of ultrasound for this aim seems promising, but is still relatively unexplored. A method using ultrasound for bladder wall thickness quantification in rats was developed and applied to measure early radiation-induced bladder wall thickness changes.

Methods

Two groups (n = 9 each) of female Fischer rats were treated with a single radiation dose of 25–30 and 35–40 Gy respectively, using an image-guided micro-irradiator; six untreated rats were monitored as a control group. Empty, half-filled and fully-filled bladder volumes were determined for four non-irradiated rats by measuring axes from ultrasound 3D-images and applying the ellipsoid formula. Mean bladder wall thickness was estimated for both ventral and dorsal bladder sides through the measurement of the bladder wall area along a segment of 4 mm in the central sagittal scan, in order to minimize operator-dependence on the measurement position. Ultrasound acquisitions of all fully-filled rat bladders were also acquired immediately before, and 4 and 28 days after irradiation. Mean bladder wall thickness normalized to the baseline value and corrected for filling were then used to evaluate acute bladder wall thickening and to quantify the dose–effect.

Results

The relationship between mean bladder wall thickness and volume in unirradiated rats showed that for a bladder volume > 1.5 mL the bladder wall thickness is almost constant and equal to 0.30 mm with variations within ± 15%. The average ratios between post and pre irradiation showed a dose–effect relationship. Bladder wall thickening was observed for the 25–30 Gy and 35–40 Gy groups in 2/9 (22%) and 5/9 (56%) cases at day 4 and in 4/9 (44%) and 8/9 (89%) cases at day 28, respectively. The two groups showed significantly different bladder wall thickness both relative to the control group (p < 0.0001) and between them (p = 0.022). The bladder wall thickness increment was on average 1.32 ± 0.41, and was 1.30 ± 0.21 after 25–30 Gy and 1.47 ± 0.29 and 1.90 ± 0.83 after 35–40 Gy at days 4 and 28 respectively.

Conclusions

The feasibility of using ultrasound on a preclinical rat model to detect bladder wall thickness changes after bladder irradiation was demonstrated, and a clear dose–effect relationship was quantified. Although preliminary, these results are promising in addressing the potential role of this non-invasive approach in quantifying radiation cystitis.

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

INTRODUCTION AND HYPOTHESIS

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.

METHODS

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).

RESULTS

Twenty women participated, with an average age of 27.95 ± 3.15 years. 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.

CONCLUSIONS

The intra- and inter-rater reliability for both the post-void residual volume and measurement of the bladder dimensions showed excellent agreement.