Ultrasound measurements of DWT. The mucosa (lower line) and adventitia of the bladder (upper line) appear hyperechogenic; the hypoechogenic area between those lines represents the detrusor and DWT (↕). The figure shows DWT measurements of four BPH patients (all 9.8 enlarged). (A) No BOO (A1, DWT 1.7–1.8 mm). (B–D) Varying degrees of BOO ([B] B3 obstruction with a DWT of 2.4 mm; [C] C1 obstruction with a DWT of 3.1 mm; [D] D4 obstruction with a DWT of 6.1 mm). DWT = detrusor wall thickness; BPH = benign prostatic hyperplasia; BOO = bladder outlet obstruction.