Bladder Diameter Research Articles

Obstructive or non-obstructive megacystis: a prenatal dilemma.

Diagnosis of prenatal megacystis has a significant impact on the pregnancy, as it can have severe adverse effects on fetal and neonatal survival and renal and pulmonary function. The study aims to investigate the natural history of fetal megacystis, to try to differentiate in utero congenital lower urinary tract obstruction (LUTO) from non-obstructive megacystis, and, possibly, to predict postnatal outcome. A retrospective single-center observational study was conducted from July 2015 to November 2023. The inclusion criteria were a longitudinal bladder diameter (LBD) >7 mm in the first trimester or an overdistended/thickened-walled bladder failing to empty in the second and third trimesters. Close ultrasound follow-up, multidisciplinary prenatal counseling, and invasive and non-invasive genetic tests were offered. Informed consent for fetal autopsy was obtained in cases of termination of pregnancy or intrauterine fetal demise (IUFD). Following birth, neonates were followed up at the same center. Patients were stratified based on diagnosis: LUTO (G1), urogenital anomalies other than LUTO ("non-LUTO") (G2), and normal urinary tract (G3). This study included 27 fetuses, of whom 26 were males. Megacystis was diagnosed during the second and third trimesters in 92% of the fetuses. Of the 27 fetuses, 3 (11.1%) underwent an abortion, and 1 had IUFD. Twenty-three newborns were live births (85%) at a mean gestational age (GA) of 34 ± 2 weeks. Two patients (neonates) died postnatally due to severe associated malformations. Several prenatal parameters were evaluated to differentiate patients with LUTO from those with non-LUTO, including the severity of upper tract dilatation, keyhole sign, oligohydramnios, LBD, and GA at diagnosis. However, none proved predictive of the postnatal diagnosis. Similarly, none of the prenatal parameters evaluated were predictive of postnatal renal function. The diagnosis of megacystis in the second and third trimesters was associated with live births in up to 85% of cases, with LUTO identified as the main cause of fetal megacystis. This potentially more favorable outcome, compared to the majority reported in literature, should be taken into account in prenatal counseling. Megacystis is an often misinterpreted antennal sign that may hide a wide range of diagnoses with different prognoses, beyond an increased risk of adverse renal and respiratory outcomes.

Fetal lower urinary tract obstruction: international Delphi consensus on management and core outcome set.

To reach an international expert consensus on the diagnosis, prognosis and management of fetal lower urinary tract obstruction (LUTO) by means of a Delphi procedure, and to use this to define a core outcome set (COS). A three-round Delphi procedure was conducted among an international panel of experts in fetal LUTO. The panel was provided with a list of literature-based parameters to consider for the diagnosis, prognosis, management and outcomes of LUTO. A parallel procedure was conducted with patient groups during the development of the COS. A total of 168 experts were approached, of whom 99 completed the first round and 80/99 (80.8%) completed all three rounds of the study questionnaires. Consensus was reached that, in the first trimester, an objective measurement of longitudinal bladder diameter of ≥ 7 mm should be used to suspect LUTO. In the second trimester, imaging parameters suggestive of LUTO could include enlarged bladder, keyhole sign, bladder wall thickening, bilateral hydronephrosis, bilateral hydroureteronephrosis and male sex. There was 79% agreement that the current prognostic scoring systems in the literature should not be used clinically. However, experts agreed on the value of amniotic fluid volume (at < 24 weeks) to predict survival and that the value of fetal intervention is to improve the chance of neonatal survival. Experts endorsed sonographic parameters suggestive of renal dysplasia, at least one vesicocentesis, and renal biochemistry for prognosis and counseling, but these items did not reach a consensus for determining candidacy for fetal intervention. On the other hand, imaging parameters suggestive of LUTO, absence of life-limiting structural or genetic anomalies, gestational age of ≥ 16 weeks and oligohydramnios (defined as deepest vertical pocket < 2 cm) should be used as candidacy criteria for fetal intervention based on expert consensus. If bladder refill was evaluated, it should be assessed subjectively. Vesicoamniotic shunt should be the first line of fetal intervention. In the presence of suspected fetal renal failure, serial amnioinfusion should be offered only as an experimental procedure under research protocols. A COS for future LUTO studies was agreed upon. International consensus on the diagnosis, prognosis and management of fetal LUTO, as well as the COS, should inform clinical care and research to optimize perinatal outcomes. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Design and optimization of the magnetic field-driven spherical gripper with adjustable stiffness

This paper presents a new gripping technique that merges the variable stiffness characteristics of conventional magnet-controlled and negative-pressure spherical grippers to produce a spherical gripper capable of securely grasping large and structurally diverse objects. The proposed method incorporates the smart rheological material from magnet-controlled grippers with the particle-jamming smart structure used in negative-pressure grippers. The gripper comprises a magnetic control device and a spherical variable stiffness body. Simulation analysis was used to optimize its structure and enhance the efficiency ratio of the magnetic control device. The flexible variable stiffness body was initially designed to be cylindrical to increase interlocking with objects. Experiments were conducted to evaluate the gripping efficiency and adaptability of the magnetron spherical gripper, which were designed to simulate real-world application requirements. These results suggest that the magnetically controlled spherical gripper can achieve a gripping efficiency of approximately five and securely grasp objects with a relative bladder diameter ranging from 20 % to 130 %. Furthermore, it can stably grip objects up to an offset distance of 15 mm without requiring sensor assistance. The enhanced magnetic field-powered spherical gripper exhibits superior adaptability and efficiency in gripping compared to its counterpart. In addition, it boasts robust resistance against environmental interference.

Effect of Material Properties on Fiber-Shaped Pneumatic Actuators Performance

Thin fiber-shaped pneumatic artificial muscle (PAM) can generate contractile motions upon stimulation, and it is well known for its good compliance, high weight-to-power ratio, resemblance to animal muscle movements, and, most importantly, the capability to be integrated into fabrics and other textile forms for wearable devices. This fiber-shaped device, based on McKibben technology, consists of an elastomeric bladder that is wrapped around by a braided sleeve, which transfers radial expansion into longitudinal contraction due to the change in the sleeve’s braiding angle while being inflated. This paper investigates the effect of material properties on fiber-shaped PAM’s behavior, including the braiding yarn and bladder’s dimensional and mechanical properties. A range of samples with combinations of yarn and bladder parameters were developed and characterized. A robust fabrication process verified through several calibration and control experiments of PAM was applied, which ensured a more accurate characterization of the actuators. The results demonstrate that material properties, such as yarn stiffness, yarn diameter, bladder diameter, and bladder hardness, have significant effects on PAMs’ deformation strains and forces generated. The findings can serve as fundamental guidelines for the future design and development of fiber-shaped pneumatic actuators.

Urine flow acceleration in healthy children: A retrospective cohort study.

To establish normal reference values of urine flow acceleration (Qacc ) in healthy children, as there is a lack of nomograms for normative reference values of Qacc by voided volumes in the pediatric population so far. Qacc might be an early indicator of autonomic neuropathy in children and adolescents. Data were retrospectively collected from healthy children who underwent uroflowmetry between 1990 and 1992. Exclusion criteria were voided volume less than 20 ml, and postvoid residual more than 15%. Baseline characteristics and uroflowmetry parameters were collected from girls and boys aged between 6 and 18 years. Voided volume, voiding time, time to maximum flow rate, and maximum and average flow rates of urine were measured, and Qacc was calculated. Postvoid bladder diameter was measured by ultrasonography and converted to volume. Uroflowmetry parameters of 208 children (≤18 years old, 45.2% girls, mean age 9.68 ± 3.09 years) who performed 404 micturition were analyzed. Median voided volume, voiding time, time to Qmax , Qave , Qmax , Qacc , and postvoid residual volume were 130 [20-460] ml, 10 [3-56] s, 3 [1-14] s, 11.7 [2.5-36.6] ml/s, 20.5 [5-50] ml/s, 6 [0.81-25] ml/s2 , and 1.83 [0-38.62] ml, respectively. Qacc nomograms were given in centile forms for girls and boys separately, which show an inversely proportional correlation between voided volumes. These are the first nomograms for normative reference values of Qacc in the pediatric population (girls and boys separately) by voided volumes in centile forms. These may be useful to interpret abnormal Qacc values and diagnose lower urinary tract diseases over a wide range of voided volumes.

Z-scores of fetal bladder size for antenatal differential diagnosis between posterior urethral valves and urethral atresia.

ABSTRACTObjectiveTo construct reference values for fetal urinary bladder distension in pregnancy and use Z‐scores as a diagnostic tool to differentiate posterior urethral valves (PUV) from urethral atresia (UA).MethodsThis was a prospective cross‐sectional study in healthy singleton pregnancies aimed at constructing nomograms of fetal urinary bladder diameter and volume between 15 and 35 weeks' gestation. Z‐scores of longitudinal bladder diameter (LBD) were calculated and validated in a cohort of fetuses with megacystis with ascertained postnatal or postmortem diagnosis, collected from a retrospective, multicenter study. Correlations between anatomopathological findings, based on medical examination of the infant or postmortem examination, and fetal megacystis were established. The accuracy of the Z‐scores was evaluated by receiver‐operating‐characteristics (ROC)‐curve analysis.ResultsNomograms of fetal urinary bladder diameter and volume were produced from three‐dimensional ultrasound volumes in 225 pregnant women between 15 and 35 weeks of gestation. A total of 1238 urinary bladder measurements were obtained. Z‐scores, derived from the fetal nomograms, were calculated in 106 cases with suspected lower urinary tract obstruction (LUTO), including 76 (72%) cases with PUV, 22 (21%) cases with UA, four (4%) cases with urethral stenosis and four (4%) cases with megacystis‐microcolon‐intestinal hypoperistalsis syndrome. Fetuses with PUV showed a significantly lower LBD Z‐score compared to those with UA (3.95 vs 8.83, P < 0.01). On ROC‐curve analysis, we identified 5.2 as the optimal Z‐score cut‐off to differentiate fetuses with PUV from the rest of the study population (area under the curve, 0.84 (95% CI, 0.748–0.936); P < 0.01; sensitivity, 74%; specificity, 86%).Conclusions Z‐scores of LBD can distinguish reliably fetuses with LUTO caused by PUV from those with other subtypes of LUTO, with an optimal cut‐off of 5.2. This information should be useful for prenatal counseling and management of LUTO. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Megacystis in the first trimester of pregnancy: Prognostic factors and perinatal outcomes.

To determine whether bladder size is associated with an unfavorable neonatal outcome, in the case of first-trimester megacystis. This was a retrospective observational study between 2009 and 2019 in two prenatal diagnosis centers. The inclusion criterion was an enlarged bladder (> 7 mm) diagnosed at the first ultrasound exam between 11 and 13+6 weeks of gestation. The main study endpoint was neonatal outcome based on bladder size. An adverse outcome was defined by the completion of a medical termination of pregnancy, the occurrence of in utero fetal death, or a neonatal death. Neonatal survival was considered as a favorable outcome and was defined by a live birth, with or without normal renal function, and with a normal karyotype. Among 75 cases of first-trimester megacystis referred to prenatal diagnosis centers and included, there were 63 (84%) adverse outcomes and 12 (16%) live births. Fetuses with a bladder diameter of less than 12.5 mm may have a favorable outcome, with or without urological problems, with a high sensitivity (83.3%) and specificity (87.3%), area under the ROC curve = 0.93, 95% CI (0.86-0.99), p< 0.001. Fetal autopsy was performed in 52 (82.5%) cases of adverse outcome. In the 12 cases of favorable outcome, pediatric follow-up was normal and non-pathological in 8 (66.7%). Bladder diameter appears to be a predictive marker for neonatal outcome. Fetuses with smaller megacystis (7-10 mm) have a significantly higher chance of progressing to a favorable outcome. Urethral stenosis and atresia are the main diagnoses made when first-trimester megacystis is observed. Karyotyping is important regardless of bladder diameter.

The Influences of Bladder Properties on the Working Performance of the Multibladder-Type Inflatable Anchor

Due to the high bearing capacity and better controllability of bladder parameters, the multibladder-type inflatable anchor shows a great application prospect in the engineering construction in soft soil areas. In this study, based on a soft soil foundation pit project in Guangzhou Province, China, the multibladder-type inflatable anchor was applied to the engineering practice for the first time, and the working characteristics of the multibladder-type inflatable anchor were analyzed and discussed through field experiments. Primarily, the optimization design and experimental facility of the multibladder-type inflatable anchor were introduced in detail to realize the refinement and perfection of the anchorage technological process. Besides, the influence degrees of the bladder number, diameter, thickness, space, and length on the bearing characteristics and deformation control of the anchor were studied by using the control variable method, as well as the influencing mechanisms. Subsequently, the advantages of the multibladder-type inflatable anchor were presented by comparing its anchoring efficacy with that of the traditional grouting anchor. Ultimately, the analysis results were used to verify the reliability of the multibladder-type inflatable anchor and provide the experimental basis for its popularization and application.

Impact of anatomical changes on radiation absorbed dose of prostate and bladder in a potential scenario of magnetic resonance imaging (MRI)-guided carbon-ion radiotherapy (MRgCT) of prostate cancer

In this study, the impact of anatomical changes on radiation dose variations of the prostate and bladder (as an organ at risk) was assessed for a potential scenario of magnetic resonance imaging-guided carbon-ion radiotherapy (MRgCT) of prostate cancer. To achieve this goal, carbon-ion beams perpendicular to a pelvis phantom affected by 1.5 T perpendicular magnetic field were simulated using the FLUKA code. Prostate diameter change from 6 to 1 cm leads to a prostate dose reduction of 88%. Bladder diameter change from 10 to 5 cm leads to a reduction of 92% in bladder dose. The set-up error of 5 mm leads to a decrease of 5% in the prostate dose. Rectum diameter change from 5 to 3 cm leads to reductions of 20% and 26% in prostate and bladder dose, respectively. In conclusion, anatomical changes impact on dose variations in MRgCT of prostate cancer.

Bladder Volume Assessment in Pediatric Patients With Neurogenic Bladder: Is Ultrasound an Accurate Method?

ObjectiveTo define the accuracy of ultrasound to determine bladder volume in pediatric patients with neurogenic bladder (NB). MethodsRetrospective analysis of children with NB in treatment with urethral clean intermittent catheterization. Exclusion criteria: bladder surgeries, and catheterization through a channel different than urethra. Bladder volume was measured with ultrasound using the formula: anteroposterior bladder diameter by side to side diameter by distance from dome to outlet tract by 0.523 (cm3). In the same act, the patient was performed urethral catheterization and the drained volume was measured in millimeters. Finally, postvoid residual volume (PVR) was assessed with ultrasound. ResultsWe performed 318 measurements in 299 patients, mean age was 9.95 years (standard deviation: 4.6), 59% were female. Most frequent etiologies of NB were myelomeningocele and lipomyelomeningocele. Mean ultrasound-determined bladder volume was 213.9cm3 (range: 20-899 cm3) and mean bladder volume drain through catheterization was 336.4 mL (range: 30-1480 mL; P : .0001). In 67.3% of the patients (n: 214) PVR was not significant, and their mean ultrasound volume was 212.7 mL and the volume evacuated by catheterization was 339.9 mL (P : .0001). In all age groups ultrasound-determined bladder volume was statistically lower than catheterized bladder volume (P : .0001). The mean percentage error of the ultrasound-determined bladder volume was 15.58% ± 44.09. Linear regression analysis and Bland-Altman plot showed low agreement between both measurement techniques. ConclusionIn children with NB, ultrasound-determined bladder volume was statistically lower than catheterized bladder volume measured at the same moment, and this relation persisted regardless of sex, age, and the presence of PVR.

Vesicoamniotic shunting for fetal megacystis in the first trimester with a Somatex\xae intrauterine shunt

PurposeThe objective was to evaluate the feasibility of vesicoamniotic shunting (VAS) in the first trimester with the Somatex® intrauterine shunt and report on complications and neonatal outcome.MethodsRetrospective cohort study of all VAS before 14 weeks at two tertiary fetal medicine centres from 2015 to 2018 using a Somatex® intrauterine shunt. All patients with a first trimester diagnosis of megacystis in male fetuses with a longitudinal bladder diameter of at least 15 mm were offered VAS. All patients that opted for VAS after counselling by prenatal medicine specialists, neonatologists and pediatric nephrologists were included in the study. Charts were reviewed for complications, obstetric and neonatal outcomes.ResultsTen VAS were performed during the study period in male fetuses at a median GA of 13.3 (12.6–13.9) weeks. There were two terminations of pregnancy (TOP) due to additional malformations and one IUFD. Overall there were four shunt dislocations (40%); three of those between 25–30 weeks GA.Seven neonates were born alive at a median GA of 35.1 weeks (31.0–38.9). There was one neonatal death due to pulmonary hypoplasia. Neonatal kidney function was normal in the six neonates surviving the neonatal period. After exclusion of TOP, perinatal survival was 75%, and 85.7% if only live-born children were considered.ConclusionVAS in the first trimester is feasible with the Somatex® Intrauterine shunt with low fetal and maternal complication rates. Neonatal survival rates are high due to a reduction in pulmonary hypoplasia and the rate of renal failure at birth is very low. VAS can be safely offered from the late first trimester using the Somatex® intrauterine shunt.

Development and evaluation of automated ultrasonographic detection of bladder diameter for estimation of bladder urine volume.

Bladder urine volume has been estimated using an ellipsoid method based on triaxial measurements of the bladder extrapolated from two-dimensional ultrasound images. This study aimed to automate this process and to determine the accuracy of the automated estimation method for normal and small amounts of urine. A training set of 81 pairs of transverse and longitudinal ultrasound images were collected from healthy volunteers on a tablet-type ultrasound device, and an automatic detection tool was developed using them. The tool was evaluated using paired transverse/longitudinal ultrasound images from 27 other healthy volunteers. After imaging, the participants voided and their urine volume was measured. For determining accuracy, regression coefficients were calculated between estimated bladder volume and urine volume. Further, sensitivity and specificity for 50 and 100 ml bladder volume thresholds were evaluated. Data from 50 procedures were included. The regression coefficient was very similar between the automatic estimation (β = 0.99, R2 = 0.96) and manual estimation (β = 1.05, R2 = 0.97) methods. The sensitivity and specificity of the automatic estimation method were 88.5% and 100.0%, respectively, for 100 ml and were 94.1% and 100.0%, respectively, for 50 ml. The newly-developed automated tool accurately and reliably estimated bladder volume at two different volume thresholds of approximately 50 ml and 100 ml.

Fetal megacystis: a lot more than LUTO.

ABSTRACTObjectiveFetal megacystis presents a challenge in terms of counseling and management because of its varied etiology and evolution. The aim of this study was to present a comprehensive overview of the underlying etiologies and structural anomalies associated with fetal megacystis.MethodsThis was a retrospective multicenter study of cases referred to the fetal medicine unit of one of the eight academic hospitals in The Netherlands with a diagnosis of fetal megacystis. For each case, data on and measurements of fetal urinary tract and associated structural anomalies were collected. All available postmortem examinations and postnatal investigations were reviewed in order to establish the final diagnosis. In the first trimester, fetal megacystis was defined as longitudinal bladder diameter (LBD) ≥ 7 mm, and in the second and third trimesters as an enlarged bladder failing to empty during an extended ultrasound examination lasting at least 40 min.ResultsOf the 541 pregnancies with fetal megacystis, it was isolated (or solely accompanied by other signs of lower urinary tract obstruction (LUTO)) in 360 (67%) cases and associated with other abnormal ultrasound findings in 181 (33%) cases. The most common associated ultrasound anomaly was an increased nuchal translucency thickness (22%), followed by single umbilical artery (10%) and cardiac defect (10%). A final diagnosis was established in 418 cases, including 222 (53%) cases with isolated LUTO and 60 (14%) infants with normal micturition or minor isolated urological anomalies. In the remaining 136 (33%) cases, concomitant developmental or chromosomal abnormality or genetic syndrome was diagnosed. Overall, 40 chromosomal abnormalities were diagnosed, including trisomy 18 (n = 24), trisomy 21 (n = 5), Turner syndrome (n = 5), trisomy 13 (n = 3) and 22q11 deletion (n = 3). Thirty‐two cases presented with anorectal malformations involving the anus, rectum and urogenital tract. In cases with confirmed urethral and anal atresia, megacystis occurred early in pregnancy and the bladder appeared severely distended (the LBD (in mm) was equal to or greater than twice the gestational age (in weeks)). Fetal macrosomia was detected in six cases and an overgrowth syndrome was detected in four cases, comprising two infants with Beckwith–Wiedemann syndrome and two with Sotos syndrome. Megacystis‐microcolon‐intestinal hypoperistalsis syndrome was diagnosed in five (1%) cases and prenatally suspected only in one case.ConclusionsAlthough the main cause of fetal megacystis is LUTO, an enlarged fetal bladder can also be present as a concomitant finding of miscellaneous genetic syndromes, developmental disturbances and chromosomal abnormalities. We provide an overview of the structural anomalies and congenital disorders associated with fetal megacystis and propose a practical guide for the differential diagnosis of genetic syndromes and chromosomal and developmental abnormalities in pregnancies presenting with fetal megacystis, focusing on the morphological examination of the fetus. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Use of Ultrasound Urodynamics to Identify Differences in Bladder Shape Between Individuals With and Without Overactive Bladder.

The objective of this study was to identify differences in bladder shape changes between individuals with overactive bladder (OAB) and unaffected individuals during ultrasound urodynamics. A prospective urodynamic study was performed with concurrent transabdominal ultrasound (ultrasound urodynamics) on individuals with and without OAB based on validated International Consultation on Incontinence Questionnaire - OAB survey scores. Three-dimensional ultrasound images were acquired at 1-minute increments during filling and used to measure bladder diameters in the height, width, and depth orientations. The engineering strain for each diameter was compared between participants with OAB and controls during urodynamic filling. The height-to-width ratio at capacity was used to determine if individuals were shape outliers. A total of 22 subjects were enrolled, including 11 with OAB and 11 without OAB. During urodynamic filling in both groups, the greatest degree of geometric strain was found in the height orientation, indicating that bladders generally fill in a craniocaudal shape. The mean ± SD height-to-width ratio of the control group was 1.06 ± 0.12 yielding a 95% confidence interval of 0.82 to 1.30. Five (45.5%) of 11 OAB subjects had height-to-width ratios outside this interval as compared with none of the control subjects, identifying a potential shape-mediated subgroup of OAB. Three-dimensional ultrasound urodynamics can be used to identify differences in bladder shape comparing individuals with and without OAB. This method may be used to identify a subset of OAB patients with abnormal bladder shapes which may play a role in the pathophysiology of their OAB symptoms.

Antenatal Workup of Early Megacystis and Selection of Candidates for Fetal Therapy

Objective: To investigate the best criteria for discriminating fetuses with isolated posterior urethral valves from those theoretically not eligible for fetal treatment because of complex megacystis, high chance of spontaneous resolution, and urethral atresia. Methods: A retrospective national study was conducted in fetuses with megacystis detected before 17 weeks’ gestation (early megacystis). Results: In total, 142 cases with fetal megacystis were included in the study: 52 with lower urinary tract obstruction, 29 with normal micturition at birth, and 61 with miscellaneous syndromal associations, chromosomal and multiple structural abnormalities (complex megacystis). Only a nuchal translucency > 95th centile, and not a longitudinal bladder diameter ≤15 mm (p = 0.24), significantly increased the risk of complex megacystis (p < 0.01). Cases with a high chance of spontaneous resolution were identified by using the cut-off of 12 mm, as demonstrated in a previous study, and the finding of an associated umbilical cord cyst carried a high-risk of urethral atresia (odds ratio: 15; p = 0.026), an unfavorable condition for antenatal treatment. An algorithm encompassing these three criteria demonstrated good accuracy in selecting fetuses theoretically eligible for fetal treatment (specificity 73%; sensitivity 92%). Conclusions: Cases theoretically eligible for early fetal therapy are those with normal nuchal translucency, a longitudinal bladder diameter > 12 mm, and without ultrasound evidence of umbilical cord cysts.

Early fetal megacystis: Is it possible to predict the prognosis in the first trimester?

To evaluate the best management of fetal megacystis diagnosed in the first trimester and define the prognosis and the most appropriate follow-up as early as possible. This is a retrospective study of first-trimester fetal megacystis diagnosed in pregnant women who performed a combined screening for fetal aneuploidy. Megacystis was defined as a longitudinal bladder diameter (LBD) greater than 7 mm. All fetuses were divided into two groups according to the LBD: Group A with LBD > 15 mm and Group B with LBD < 15 mm. The fetal karyotype and associated anomalies were evaluated. Ultrasound monitoring was performed every 2 weeks (a second ultrasound scan after 2 weeks from diagnosis and a third ultrasound scan 2 weeks after the second one). Twenty-six cases were identified between 2011 and 2016; three cases of aneuploidy were excluded from the study. Of the remaining 23 cases, 11 were included in Group A and 12 in Group B. All Group A fetuses had an adverse outcome. In Group B: five (41.7%) cases had an adverse outcome and seven (58.3%) had a spontaneous resolution of megacystis. The ultrasound findings of both the ultrasound scans, the second and the third, were 100% concordant. An ultrasound scan performed 2 weeks after the megacystis diagnosis can predict the outcome in fetuses with an LBD < 15 mm as early as the end of the first trimester. The outcome of euploid fetuses with an LBD < 15 mm was favorable in 58.3% of the cases.

Fetal megacystis: prediction of spontaneous resolution and outcome.

To investigate the natural history of fetal megacystis from diagnosis in utero to postnatal outcome, and to identify prognostic indicators of spontaneous resolution and postnatal outcome after resolution. This was a national retrospective cohort study. Fetal megacystis was defined in the first trimester as a longitudinal bladder diameter (LBD) ≥ 7 mm, and in the second and third trimesters as an enlarged bladder failing to empty during the entire extended ultrasound examination. LBD and gestational age (GA) at resolution were investigated with respect to likelihood of resolution and postnatal outcome, respectively. Sensitivity, specificity and area under the receiver-operating characteristics curve (AUC) were calculated. In total, 284 cases of fetal megacystis (93 early megacystis, identified before the 18th week, and 191 late megacystis, identified at or after the 18th week) were available for analysis. Spontaneous resolution occurred before birth in 58 (20%) cases. In cases with early megacystis, LBD was predictive of the likelihood of spontaneous resolution (sensitivity, 80%; specificity, 79%; AUC, 0.84), and, in the whole population, GA at regression was predictive of postnatal outcome, with an optimal cut-off at 23 weeks (sensitivity, 100%; specificity, 82%; AUC, 0.91). In the group with early megacystis, the outcome was invariably good when resolution occurred before the 23rd week of gestation, whereas urological sequelae requiring postnatal surgery were diagnosed in 3/8 (38%) cases with resolution after 23 weeks. In the group with late megacystis, spontaneous resolution was associated with urological complications after birth, ranging from mild postnatal hydronephrosis in infants with resolution before 23 weeks, to more severe urological anomalies requiring postnatal surgery in those with resolution later in pregnancy. This supports the hypothesis that an early resolution of megacystis is often related to a paraphysiological bladder enlargement that resolves early in pregnancy without consequences, while antenatal resolution occurring later in pregnancy (after the 23rd week of gestation) should suggest a pathological condition with urological sequelae. In fetal megacystis, LBD and GA at regression can be used as predictors of resolution and outcome, respectively. These parameters could help in fine-tuning the prognosis and optimizing the frequency of follow-up scans. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Intra-Rater Reliability of Rehabilitative Ultrasound Imaging for Multifidus Muscles Thickness and Cross Section Area in Healthy Subjects.

Introduction:Rehabilitative Ultrasound Imaging (RUSI) must be valuable method for research and rehabilitation. So, the reliability of its measurements must be determined. The purpose of this study was to evaluate the intra-rater reliability of RUSI for measurement of multifidus (MF) muscles cross section areas (CSAs), bladder wall diameter, and thickness of MF muscles between 2 sessions in healthy subjects.Method:Fifteen healthy subjects through simple non-probability sampling participated in this single-group repeated-measures reliability study. MF muscles thickness at rest and during contraction, MF muscles CSAs at rest, and bladder diameters at rest and during pelvic floor muscles (PFM) contraction were measured through RUSI. Pearson’s correlation coefficient test was used to determine intra-rater reliability of variables.Finding:The results showed that intra-class correlation Coefficient (ICCs) values with 95% confidence interval (CI) and the standard error of the measurement (SEM) were good to excellent agreement for a single investigator between measurement occasions. The intra-rater reliability for the bladder wall displacement was high (ICCs for rest and PFM contraction state: 0.96 and 0.95 respectively), for the MF muscles CSAs at the L4 level was good to high (ICCs 0.75 and 0.91 for right (Rt) and left (Lt) side respectively), and for the thickness of MF muscles at two levels, at rest and during two tasks was moderate to high (ICCs: 0.64 to 0.87).Conclusion:The Trans-Abdominal (TA) method of RUSI is a reliable method to quantify the PFM contraction in healthy subjects. Also, the RUSI is a reliable method to measure the MF muscles CSAs, the MF muscles thickness at rest and during functional tasks in healthy subjects.

P02.05: Outcome of fetal diagnosis of megacystis

To evaluate the frequency of associated anomalies and outcome of fetal megacystis according to bladder dimension and gestational age (GA) at diagnosis. Seventy-four cases of fetal megacystis, seen over a 10 year period, were retrospectively reviewed for antenatal ultrasound features and outcome. Before the 14th week of gestation, severe megacystis was defined as a longest bladder diameter more than 15 mm; after the 14th week, as a bladder length of more than GA in weeks + 12 (Maizels et al.). All other cases of referrals for bladder enlargement were defined as moderate. Fetal megacystis was identified before the 14th week of gestation in 31 cases; at 14 - 25 weeks in 31 cases and after the 25th week in 12 cases. Severe megacystis was described in 31 cases; moderate megacystis in 34 fetuses. Of all cases diagnosed early in pregnancy (<14th week), the only 3 chromosomal abnormalities occurred in fetuses with moderate megacystis (<15mm). Spontaneous resolution of the megacystis also occurred in 9 cases of moderate megacystis. These fetuses were all liveborn. There were no livebirths with early diagnosed severe megacystis. Of cases diagnosed after the 14th week, all fetuses with severe megacystis had posterior urethral valve (8) and no spontaneous resolution was seen. The outcome of fetal megacystis can be predicted by bladder size and gestational age at diagnosis. Fetal megacystis diagnosed before the 14th week and with a maximum diameter of < than 15 mm is associated with a high rate of congenital anomalies, in particular chromosomal defects. Based on bladder sixe, at any gestational age the main cause of severe megacystis, is lower urinary tract obstruction.

New evidence for old lore – Urinary bladder distension on post-mortem computed tomography is related to intoxication

IntroductionDistension of the urinary bladder is reported to be a sign of intoxication at autopsy. The purpose of this study was to compare radiologically calculated urinary bladder volume (UBV) to autopsy measurements of UBV, and to investigate the relationship between intoxication and calculated UBV. Materials and methodsAutopsy reports, toxicology reports and post-mortem CTs of 332 adult human cadavers were retrospectively analyzed, 259 cases were included in the final population. Spearman's rho test was used to compare calculated UBV to autopsy measurements. Significance levels for UBV in relation to toxicology results were investigated with the Mann–Whitney test. Spearman's rho test was also used to correlate the widest left–right bladder diameter on axial images to calculated UBV. Both calculated UBV and axial diameters were subjected to receiver operating characteristics curve analysis. Sensitivity and specificity were calculated for individual cutoff values. ResultsThere is a strong correlation and high consistency (r=0.92, p<0.001) between the measured and calculated UBV. Positive toxicology results strongly correlate with calculated UBV (p<0.001). Additionally, there is a strong correlation between calculated UBV and axial urinary bladder diameter (p<0.001). UBV of 182ml and >330ml indicate positive toxicology results with a sensitivity/specificity of 40%/87% and 25%/97% respectively. Axial urinary bladder diameter of 8.5cm and >10cm indicate positive toxicology results with a sensitivity/specificity of 36%/85% and 16%/95% respectively. ConclusionsRadiologically calculated UBV accurately represents the autoptically measured UBV. The occurrence of urinary bladder distension on post-mortem imaging should raise suspicion of intoxication.