Ultrasound assessment of bladder detrusor wall thickness for non-invasive diagnosis of female bladder outlet obstruction / 中华泌尿外科杂志

ABSTRACT

Objective To evaluate the diagnostic accuracy of ultrasound bladder detrusor wall thickness (DWT) measurement for female bladder outlet obstruction (FBOO) and investigate the application of this non-invasive method for diagnosis of FBOO.Methods DWT was measured by linear ultrasound (7.5 MHz) either at a filling volume of 50％ of cystometric capacity or at 250 ml filling in 93 women undergoing pressure flow study (PFS) for lower urinary tract symptoms (LUTS).FBOO was defined as maximal flow rate (Qmax) of less than 12 ml/s combined with a detrusor pressure at maximal flow rate (Pdet Qmax)greater than 25 cm H2O.All the patients were divided into 2 groups according to FBOO and non-FBOO.The age,urodynamic parameters and DWT of the 2 groups were compared.Meanwhile DWT was evaluated for diagnosing BOO through receiver operating characteristic (ROC) curve.ResultsThe age (61.2 ± 8.3 vs 59.9 ± 7.7 years,P =0.44) and maximal cystometric capacity (292.2 ± 82.3 vs 308.1 ± 87.5 ml,P =0.37 ) between the 2 groups had no significant difference.DWT was significantly higher ( P =0.00 ) in FBOO group (42 cases,DWT 1.8 ±0.3 mm) compared to non-FBOO group (51 cases,1.4 ±0.2 mm).Furthermore maximal detrusor pressure (43.1 ± 11.2 vs 16.2 ± 7.1 cm H2O,P =0.00),Pdet Qmax (34.3 ±8.2 vs 13.1 ±7.8 cm n2O,P =0.00),Qmax(7.4 ±3.2 vs 17.4 ±4.1 ml/s,P =0.00),voided volume (157.1 ±63.7 vs 251.2 ±77.4 ml,P=0.00) and post-void residual volume (117.5 ±71.3 vs 37.7 ± 18.1 ml,P =0.00) had significant differences between the 2 groups.For a diagnosis of FBOO,DWT of 1.9 mm or greater had a positive predictive value of 100％,a negative predictive value of 62％,specificity of 100％ and sensitivity of 38％.ROC analysis revealed that DWT had a high predictive value for FBOO with an area under the curve of 0.88 ± 0.06.Conclusions Ultrasound DWT measurement for FBOO is non-invasive,convenient and reliable.DWT 1.9 mm or greater assessed by ultrasound has a high predictive value and specificity for FBOO and can replace PFS in some extent.However,this cutoff value needs to be validated in multiple center and larger population study.