Table 1.

Microtomographic findings in bladder outlet obstruction

Case	Age	US findings	PM findings	Urethral findings by microtomography
Optical projection tomography
1	14 W	Dilated bladder; renal pyelectasis	Megacystis; apparent atresia of proximal urethra; hydronephrosis; delivery by D&E	Urethral atresia
2	16 W	Megacystis	Megacystis; dilated posterior urethra with urethral atresia; delivery by D&E after IUFD	Urethral atresia
3	39 W	Megacystis; ascites and pleural effusions	Megacystis; dilated posterior urethra; “posterior urethral valves”	Type III PUV (obstructive diaphragm)
MicroCT
4	17 W	Dilated bladder with inferior keyhole appearance; echogenic kidneys with pyelectasis; ascites	Dilated urinary bladder; paucity of renal tubules and possible collapsed cysts; delivery by D&E	Urethral atresia
5	19 W	Enlarged bladder with keyhole appearance; echogenic kidneys with small cysts	Megacystis; dilated posterior urethra; obstructed urethral orifice; cystic renal dysplasia; delivery by D&E	Urethral atresia
6	19 W	Thickened bladder wall with inferior keyhole appearance; hydroureter	Megacystis; hydroureter; proximal urethral diaphragm	Type III PUV (obstructive diaphragm)
7	25 W	No prenatal care	Prune belly, phenotype, with massively distended abdomen, ascites, and hypoplastic abdominal muscles; megacystis with urethral obstruction; hydroureter; hydronephrosis	Tortuous, stenotic posterior urethra
8	31 W	Postnatal US: enlarged bladder; reproductive organs not identified in genital region, inguinal canals, or pelvis	Urethral stenosis; atypical insertion of ureters and R-V fistula (VACTERL)	Severe urethral stenosis; ectopic seminal vesicles and insertion of ureters (at dome of bladder)
9	21 W	Distended abdomen with cystic mass of uncertain location	Hydroureter; hydronephrosis; urethral atresia	Keyhole dilatation of posterior urethra, with urethral atresia
10	22 W	Enlarged bladder; keyhole appearance of posterior urethra	Megacystis; keyhole dilatation of posterior urethra with probable atresia	Megacystis; kinking of dilated posterior urethra with associated stenosis; mild poststenotic dilatation of urethra with obstructing diaphragm (COPUM) in distal-most urethra

US indicates ultrasound (prenatal unless designated otherwise); PM, postmortem; W, weeks gestation; D&E, dilatation and extraction; IUFD, intrauterine fetal demise; PUV, posterior urethral valves; R-V, rectovesical; VACTERL, association of vertebral, anal, cardiac, tracheo-esophageal, radial or renal, and limb anomalies.