膀胱超声测量膀胱壁厚度

Review Article U er of B efu r A y T El ‡ An Fro Bristol, ver M Sch Academ m, The pienza, Pu m es in be lit M pu wa Re es co en m be co di va Co th cli LO sig tie th er on po fu (b ne ag mo 002 TH © 2 rpose: In the last decade interest has arisen in the use of ultrasound derived easurements of bladder wall thickness, detrusor wall thickness and ultrasound timated bladder weight as potential diagnostic tools for conditions known to duce detrusor hypertrophy. However, to date such measurements have not en adopted into clinical practice. We performed a comprehensive review of the erature to assess the potential clinical usefulness of these measurements. aterials and Methods: A MEDLINE® search was conducted to identify all blished literature up to June 2009, investigating measurements of bladder ll thickness, detrusor wall thickness and ultrasound estimated bladder weight. sults: Measurements of bladder and detrusor wall thickness, and ultrasound timated bladder weight have been studied in men, women and children. A nvincing trend has been shown in the ability of these measurements to differ- tiate men with from those without bladder outlet obstruction. In addition, easurements of bladder wall thickness have revealed a considerable difference tween detrusor overactivity and urodynamic stress incontinence. A number of nfounding variables and a lack of standardized methodology has resulted in screpancies among studies. Therefore, reproducible diagnostic ranges or cutoff lues have not been established. nclusions: Ultrasound derived measurements of bladder and detrusor wall ickness, and ultrasound estimated bladder weight are potential noninvasive nical tools for assessing the lower urinary tract. Key Words: urinary bladder, urinary bladder neck obstruction, ultrasonography, review WER urinary tract symptoms are a nificant source of burden to the pa- nt. Of men older than 50 years in e United Kingdom 41% report mod- ate to severe LUTS.1 LUTS are sec- dary to fluid handling disorders (eg lyuria/nocturnal polyuria) or dys- nction of the lower urinary tract ladder, outflow tract or both). In urologically normal patients stor- e and voiding symptoms are com- nly due to detrusor overactivity and BOO, respectively. Adequate noninva- sive methods for diagnosing these con- ditions do not exist and, thus, pressure- volume studies of filling and PFS of voiding remain the gold standard in- vestigations. However, these tests are invasive, expensive and time-consum- ing with associated morbidity.2 Animal studies have revealed bladder wall hypertrophy and in- creased bladder weight after par- tially induced BOO,3– 8 within as lit- Abbreviations and Acronyms AUR� acute urinary retention BOO� bladder outlet obstruction BVWI� bladder volume and wall thickness index BWT� bladder wall thickness DO� detrusor overactivity DWT� detrusor wall thickness LUTS� lower urinary tract symptoms OAB� overactive bladder PFS� pressure flow studies TAUS� transabdominal ultrasound TVUS� transvaginal ultrasound UDS� urodynamics UEBW� ultrasound estimated bladder weight USI� urodynamic stress incontinence Submitted for publication November 18, 2009. Supported by a research grant provided by Verathon Medical. * Correspondence: Bristol Urological Institute, Southmead Hospital, Bristol, BS10 5NB, United Kingdom (telephone: �44117 9595690; FAX: �44117 9502229; e-mail: ebright@doctors.net.uk). † Financial interest and/or other relationship with Verathon. ‡ Financial interest and/or other relationship with Pfizer, Astellas, Verathon, Polil-Boskcamp and Bayer. § Financial interest and/or other relationship with Astellas, Novartis, Pfizer, Takeda and Orion. � Financial interest and/or other relationship with Pfizer, Astellas, Ono, Novartis and Verathon. 2-5347/10/1845-1847/0 Vol. 184, 1847-1854, November 2010 E JOURNAL OF UROLOGY® Printed in U.S.A. 010 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION AND RESEARCH, INC. DOI:10.1016/j.juro.2010.06.006 www.jurology.com 1847 ltrasound Estimated Bladd ladder Wall Thickness—Us ssessing the Lower Urinar izabeth Bright,*,† Matthias Oelke, m the Bristol Urological Institute, Southmead Hospital, ool, Hanover, Germany (MO), Department of Urology, Netherlands (MO) and 2nd School of Medicine, “La Sa Weight and Measurement l Noninvasive Methods fo ract? drea Tubaro§ and Paul Abrams� United Kingdom (EB, PA), Department of Urology, Hano ic Medical Centre, University of Amsterdam, Amsterda ” University of Rome, Rome, Italy (AT) edical tle co str tiv Hi pe de ca pa an su m ph pa et tru m in tio co no hy so dis ra es th in su ca po M A lis me ter RE BW Be be of at po to am de m tom 3.0 Th me wi fem of wa 1) lay 2) pa va de um ta cre it me gr ma sh vo te m ea re Fu ob pa de se di BW A di DW al LU sta BLADDER WEIGHT AND WALL THICKNESS ON ULTRASOUND1848 as 2 weeks.5 Mean bladder wall thickness in ntrol, partially obstructed and severely ob- ucted rabbits was 1.57, 2.04 and 2.77 mm, respec- ely, with most thickening in the detrusor layer.4 stological analysis showed smooth muscle cell hy- rtrophy and hyperplasia, and increased collagen position, ratio of type I-to-III collagen4,8 and mus- rinic cholinergic receptors.6 Similar histological tterns were observed in patients with BOO9,10 d DO,11 and in those undergoing augmentation rgery for high intravesical pressure.12 Further- ore, bladder weight, smooth muscle cell hypertro- y and collagen deposition have been shown to rtially reverse after BOO relief in pigs.7 Beamon al demonstrated concurrent development of de- sor hypertrophy and DO with induced BOO in ice at 6 weeks, which is a well-known association clinical practice.8 Historically urologists believed bladder trabecula- n to be a marker of BOO. Although studies have nfirmed this relationship,9,13 in some cases DO and t BOO may be the causative factor.14 Bladder wall pertrophy can be visualized on ultrasound. Ultra- nic measurements of BWT and bladder weight can tinguish between obstructed and nonobstructed bbit bladders.15 In the last decade increasing inter- t has arisen in the measurement of BWT/DWT and e ultrasound estimation of bladder weight as a non- vasive means of assessing LUTS. However, to date ch measurements have not been adopted into clini- l practice. We reviewed the literature to assess the tential clinical usefulness of these measurements. ATERIALS AND METHODS MEDLINE search was conducted to identify all pub- hed literature up to the end of June 2009 investigating asurements of BWT, DWT and UEBW. The search ms used were bladder weight, BWT and DWT. SULTS T/DWT in Healthy Asymptomatic Adults fore ultrasound measurement of BWT/DWT can used as a reliable clinical tool the quantification these measurements in the healthy, asymptom- ic population must be established. However, re- rts on normal measurements are few and difficult compare because of fundamental differences ong them, particularly for BWT or DWT and the gree of bladder filling at which such measure- ents should be taken. On TAUS at a variety of filling volumes in asymp- atic healthy volunteers mean BWT was 3.33 and 4 mm in 172 men and 166 women, respectively.16 is gender difference was also observed in measure- nt of the detrusor layer in 55 healthy volunteers, Fig su th a mean DWT of 1.4 and 1.2 mm in males and ales, respectively, measured at a bladder volume 250 ml or greater (fig. 1).17 Measurement of DWT s considered preferable to total BWT for 2 reasons. Previous animal studies have shown the muscle er to be mostly affected by pressure changes and the mucosa could be influenced by other bladder thology such as carcinoma or infection. In both studies wall thickness was measured at a riety of filling volumes. Although both revealed a crease in wall thickness with increasing filling vol- e, only the latter study quantified this at incremen- l measurements in the same individual.17 DWT de- ased at volumes up to 250 ml but beyond that point remained relatively static. The authors recommend asuring DWT at a filling volume of 250 ml or eater when possible. In patients for whom filling y not reach 250 ml, such as those with DO, DWT ould be estimated with the help of the DWT-bladder lume graphs generated by Oelke et al.17 Another study of asymptomatic healthy volun- ers revealed a slightly higher mean DWT of 2 m.18 As only a single measurement was taken in ch patient at a filling volume of 200 ml, these sults may reflect an underestimation of DWT.17 rthermore, images were inadequately enlarged to tain an accurate measurement and some of the tients were pretreated with �-blockers known to crease BWT/DWT. In conclusion, there is no con- nsus in the literature for age and gender specific agnostic ranges or cutoffs for BWT/DWT. T or DWT in BOO handful of studies have attempted to quantify the agnostic ability of TAUS measurements of BWT/ T in patients with suspected BOO. Hakenberg et reported a mean BWT of 3.67 mm in 150 men with TS at a variety of filling volumes.16 However, no tistically significant difference was found between ure 1. Difference in BWT and DWT measurements in same bject at bladder filling volume of 250 ml. Reduced from �8. th an 17 wa va no gr fil et BO th 1.3 str str re fil DW eq a cu 10 stu an re at to its ev th m Fig ml 6) BLADDER WEIGHT AND WALL THICKNESS ON ULTRASOUND 1849 ese men and age matched asymptomatic controls. In other study a similar mean of 4 mm was obtained in 0 men with urodynamically confirmed BOO.19 BWT s measured at a single filling volume of 150 ml. A lue of 5 mm appeared to be the best cutoff to diag- se BOO, with 88% of patients with BWT 5 mm or eater confirmed as obstructed on PFS. Based on preliminary data revealing an effect of ling volume on DWT in healthy volunteers, Oelke al assessed DWT at bladder capacity in men with O.20 DWT increased incrementally in relation to e degree of obstruction. On PFS mean DWT was 3, 1.62, 2.4 and greater than 3 mm in unob- ucted, equivocal, obstructed and severely ob- ucted patients, respectively (fig. 2). Comparable sults were reported in a similar study of DWT at ling capacity in 102 men with LUTS.21 Median T was 1.7, 1.8 and 2.7 mm in the unobstructed, uivocal and obstructed groups, respectively, with DWT of 2.9 mm or greater shown to be the best toff to diagnose BOO (positive predictive value 0%, specificity 100%, AUC 0.88). In both of these dies the difference in DWT between unobstructed d obstructed patients was statistically significant. More recently a DWT of 2 mm or greater was ported in 94% of men with BOO confirmed on UDS a filling volume of 250 ml or greater.22 Compared other clinical parameters DWT was the best test ure 2. BWT (red arrow) and DWT (yellow arrow) measurements in 4 . Patient A had LUTS but no obstruction (Schäfer grade 1). Patients B had LUTS and obstruction. A–C, reduced from �8. D, reduced from � predict BOO with an AUC of 0.93. In addition, justing the DWT threshold to 2.5 mm, as reported Kessler et al,21 revealed similar sensitivity and ecificity to that reported by Oelke et al.20,22 More cently, a study of 155 Turkish men reported a tistical difference in BWT in those with a maxi- um uroflow rate of 10 ml per second or less (mean T 4.44� 1.18 mm) compared to those with a rate eater than 10 ml per second (mean BWT 3.85 � 6 mm).23 Measurements were taken at bladder lumes between 150 and 200 ml. Although a consistent trend between BWT/DWT d BOO can be appreciated, no definitive reference nges have been established. It is likely that con- nding differences among tests, for example mea- rements at different filling volumes, are to blame. att et al observed no difference in mean DWT be- een patients with and without proven obstruction 1 vs 2 mm, respectively).18 The single measurement a filling volume of 200 ml used in this study may ve resulted in underestimation of DWT.17 trasound Estimated Bladder Weight T/DWT is affected by filling volume. Therefore, usefulness as a clinical tool becomes limited in eryday practice. Kojima et al attempted to resolve is problem by calculating bladder weight.24 TAUS easurements of intravesical volume and BWT to ad by sp re sta m BW gr 0.7 vo an ra fou su Bl tw (2. at ha Ul BW men (A to D) with BPH-LUTS at bladder filling volume of 250 (Schäfer grade 3), C (Schäfer grade 4) and D (Schäfer grade 4. we th in vo UE wi bla bla UE pe co hy tu 34 m (m an BO UE so m a l a vo wi stu m gm gm wa m AU gr M sig UE to re gr th to M or Sc pr se sh cu tio al. wh un tio us th tio im no es BW An lik be DO clo Th dis po ul su wa ob th wo wi fil sa wo UD no ov pr gr wo mm ics an am th fin for In siv re su M de wa pa sta str se wi BLADDER WEIGHT AND WALL THICKNESS ON ULTRASOUND1850 re obtained. Assuming the bladder to be a sphere, e bladder wall volume was calculated by subtract- g the intravesical volume from the total bladder lume, which includes the bladder wall. The BW was obtained by multiplying this parameter th the specific gravity. The UEBW of 10 cadaveric dders correlated significantly with the actual dder weight (r � 0.970, p �0.0001), and stable BW was observed in 16 patients measured re- atedly at filling volumes between 100 and 300 ml. Kojima et al also reported greater mean UEBW in nditions that cause BOO, such as benign prostatic perplasia, prostate cancer and urethral stric- re.25 Mean UEBW was significantly higher in obstructed men (BOO index greater than 40, ean UEBW 46.2 gm) than in 31 unobstructed men ean UEBW 29.3 gm). ROC analysis demonstrated UEBW cutoff of greater than 35 gm for predicting O with 87.9% of obstructed men having an BW greater than 35 gm. Ochiai and Kojima correlated UEBW with ultra- nic measurement of prostatic size.26 In 234 men a ean UEBW of 41.1 gm was observed in those with arger prostate compared to 27.1 gm in those with normal size prostate. A larger prostate and post- id residual volume greater than 100 ml correlated th UEBW greater than 35 gm. In a longitudinal dy of 33 men with benign prostatic hyperplasia ean UEBW decreased significantly from 52.9 to 35 4 weeks after prostatectomy compared to 26.5 in control patients.27 At 12 weeks mean UEBW s 31.6 gm and had completely normalized in the ajority of men. Miyashita et al studied UEBW in men with R.28 Of these men 90% had an UEBW of 35 gm or eater compared to only 41% of those without AUR. ultivariate analysis revealed age and UEBW to be nificant determinants of AUR, and men with an BW greater than 35 gm were 13.4 times as likely develop AUR. In a longitudinal study of men ceiving tamsulosin for LUTS, UEBW was 35 gm or eater in approximately half.29 At 5 years 81.7% of ese men had undergone prostatectomy compared only 36.2% of those with UEBW less than 35 gm. ultivariate analysis demonstrated UEBW 35 gm greater and International Prostate Symptom ore 20 or greater to be significant risk factors for oceeding to surgery. Although UEBW appears to be an attractive as- ssment method for BOO, its diagnostic power ould not be overstated. To our knowledge there is rrently no published literature from other institu- ns to confirm or dispute the findings of Kojima et 25 It is our belief that an UEBW threshold of 35 gm, ile applicable to the Japanese population, grossly derestimates bladder weight in the white popula- n based on unpublished cadaveric data by one of TA en . Therefore, we cannot conclude that UEBW greater an 35 gm is universally diagnostic of BOO. In addi- n, while a number of authors have emphasized the portance of measuring DWT rather than BWT, ne has investigated the possibility of ultrasound timated detrusor weight as a diagnostic parameter. T in Women atomical differences dictate that women are un- ely to suffer from BOO. However, a significant num- r require UDS to confirm the presence/absence of . DO produces repeated contractions against a sed sphincter, resulting in detrusor hypertrophy. us, measurements of BWT/DWT may be able to tinguish between women with and without DO. In a preliminary study of women undergoing UDS st-void BWT was measured using transvaginal trasound.30 Mean BWT was calculated from the m of 3 measurements (dome, trigone, anterior ll). A significant difference in mean BWT was served between women with DO (6.7 mm) and ose with USI (3.5). While the mean BWT in men with DO was much thicker than that in men th BOO, measurements were obtained at bladder ling volumes less than 50 ml. Khullar et al confirmed these findings in a larger mple of 180 women.31 Mean BWT was 6.3 mm in men with DO vs 3.9 mm in those with normal S, USI or mixed incontinence. Significantly as ne of the BWT measurements in women with DO erlapped those of the other diagnoses, the positive edictive value of diagnosing DO with a mean BWT eater than 5 mm was 94%. Interestingly in 42 men with stable UDS but a BWT greater than 5 additional assessment via ambulatory urodynam- confirmed the presence of DO in 36 (85.7%). In an alysis of 128 women BWT greater than 6 mm on bulatory UDS was able to differentiate between ose with DO and those with USI.32 However, these dings have not been reproduced elsewhere.33 Although TVUS is undoubtedly quicker to per- m than UDS, it still requires a skilled technician. addition, for the patient it may feel just as inva- e as TAUS. Lekskulchai and Dietz retrospectively viewed the results of translabial ultrasound mea- rement of DWT in 686 women undergoing UDS.34 easurements were taken at the dome of the blad- r with less than 50 ml filling volume. Mean DWT s 4.7 mm in 184 women diagnosed with DO com- red to 4.1 mm in the nonDO group. However, this tistically significant difference failed to demon- ate a predictive power. Using a cutoff of 5 mm, nsitivity was poor at 37% and specificity was 79% th an AUC of only 0.606. Until recently only 1 small study investigated US measurement of BWT and UEBW in wom- .35 On UDS mean UEBW was 36.5 gm in 12 wo A fil wi su in OA to ca ex di a wi Al we qu m re DW ob 10 na BW Of ac pa ar BW dr co mm of vo div lat ter a m BV pr len an ca an by wa to an cr um DW dr do bla ve bla bla str m vo ob m fa tw fer dr wi In m sy sp pa ha M sh bo via no a s wi pr (70 dr 70 DI Th fu nu is lat su sy wi eff BW lis di da on Th ve ro BLADDER WEIGHT AND WALL THICKNESS ON ULTRASOUND 1851 men with USI vs 42.6 gm in 13 with proven DO. decrease in BWT was observed with increasing ling volumes up to 400 ml. Kuo also reported a significant decrease in DWT th increasing bladder filling beyond the previously ggested static level of 250 ml.36 In 81 women, cluding 28 controls, 28 with OAB dry and 25 with B wet, a rapid decrease in DWT was observed up 250 ml filling volume. From 250 ml to bladder pacity a decrease was still observed but to a lesser tent. TAUS DWT measured at 250 ml showed no fference between the groups. At capacity however, statistically larger DWT was observed in women th OAB wet and DO compared to the other groups. though statistically significant, these differences re small (0.2 to 0.4 mm), leading the authors to estion whether they were reproducible. Further- ore, 3.5 to 7.5 MHz ultrasound scanners have a solution of approximately 0.1 to 0.3 mm,17 and T/BWT measurements have a reported intra- server and interobserver variability of 5% to %.19,20 Thus, these small differences could origi- te from variability or resolution. T in Children all patients requiring UDS, the development of an curate, easy to use, noninvasive method would be rticularly advantageous in children. Although there e a few studies assessing TAUS measurement of T/DWT in symptomatic and asymptomatic chil- en, differences in interpretation and reporting limit mparison. Wall thickness has been reported in ,7–39 and an index has been calculated in a variety ways from measurements of wall thickness, bladder lume and bladder radius.40–42 Kaefer et al recorded a bladder thickness index by iding the average