Objectives: To dene the diagnostic accuracy of intravesical protrusion of prostate (IPP), bladder wall thickness (BWT) and prostate volume (PV)
in diagnosis of bladder outlet obstruction (BOO) and prediction of future acute urinary retention (AUR). A prospective Materials and methods:
study of 127 patients, presenting with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH) were enrolled with 50
patients among them manifesting AUR. 35 normal persons were selected as control group. After inclusion, all patients underwent transabdominal
ultrasound and pressure ow urodynamic study (UDS). UDS parameter, BOO index (BOOI) were used as a reference standard for stratifying the
patients into two groups, BOO and non-BOO. The sono-morphological parameters, IPP, BWT and PV were used to compare between these two
groups with calculating the diagnostic accuracy for each individual index. IPP, BWT Results: and PV had statistically signicant difference
between group 1 (BOOI < 40) and 2 ( BOOI > 40) with strong correlation with BOOI. The Pearson's correlation coefcient (r) for IPP, BWT and PV
were 0.762, 0.702 and 0.660 respectively. The AUC for IPP, BWT and PV were 0.824, 0.786 and 0.650 with highest accuracy for IPP (79.2%) at cutoff value of 7 mm. Using the same threshold value, IPP had higher statistical difference than BWT in predicting AUR with similar diagnostic
accuracy of IPP and BWT together. IPP and BWT in conjunction with PV in place Conclusions: of UDS had good clinical utility in diagnosis of
BOO due to BPH and future AUR prediction.