Kaefer M, Barnewolt C, Retik A B, Peters C A
Department of Radiology, Children's Hospital, Boston, Massachusetts, USA.
J Urol. 1997 Mar;157(3):989-91.
The pathophysiological changes that result from posterior urethral valves depend primarily on the degree and duration of infravesical obstruction. Delayed diagnosis may result in progressive bladder dysfunction, renal parenchymal loss or sepsis. Specific radiographic and clinical criteria predictive of a diagnosis of infravesical obstruction are available in the form of voiding cystourethrography and cystoscopy. However, these modalities share the disadvantage of being invasive in nature. Although noninvasive, sonographic evaluation of bladder thickness has a high degree of variability and it markedly depends on the degree of bladder filling.
Bladder wall thickness and bladder diameter were assessed in 15 children with posterior urethral valves, and 10 age and sex matched children with no bladder dysfunction. Ultrasound was performed before intervention (that is catheter placement or valve ablation).
A positive predictive value of 93% was achieved between the 2 groups when bladder wall thickness was indexed to inner wall diameter in the anteroposterior or transverse dimension. Mean bladder wall thickness divided by mean inner bladder diameter plus or minus standard deviation was 0.402 +/- 0.25 in the obstructed population and 0.094 +/- 0.025 in controls (p = 0.0004).
The bladder thickness index is a sensitive sonographic predictor of infravesical obstruction. Application of this index as a noninvasive screening tool for the patient with persistent voiding dysfunction may prove beneficial for identifying infravesical pathology.
后尿道瓣膜引起的病理生理变化主要取决于膀胱下梗阻的程度和持续时间。诊断延迟可能导致进行性膀胱功能障碍、肾实质丧失或败血症。排尿性膀胱尿道造影和膀胱镜检查可提供预测膀胱下梗阻诊断的特定影像学和临床标准。然而，这些检查方式都具有侵入性的缺点。虽然超声评估膀胱厚度是非侵入性的，但它具有高度变异性，且明显取决于膀胱充盈程度。
对15例患有后尿道瓣膜的儿童以及10例年龄和性别匹配且无膀胱功能障碍的儿童进行膀胱壁厚度和膀胱直径评估。在进行干预（即放置导尿管或瓣膜消融）之前进行超声检查。
当膀胱壁厚度以前后径或横径的内壁直径为指标时，两组之间的阳性预测值达到93%。梗阻组平均膀胱壁厚度除以平均膀胱内径加减标准差为0.402±0.25，对照组为0.094±0.025（p = 0.0004）。
膀胱厚度指数是膀胱下梗阻的敏感超声预测指标。将该指数作为持续排尿功能障碍患者的非侵入性筛查工具，可能有助于识别膀胱下病变。
