Diagnosis of bladder outlet obstruction in men with lower urinary tract symptoms: comparison of near infrared spectroscopy algorithm and pressure flow study in a prospective study.

Objective To investigate the efficacy of near infrared spectroscopy (NIRS) and an algorithm on the diagnosis of bladder outlet obstruction in men with lower urinary tract symptoms (LUTS). Methods Male patients with LUTS were recruited and underwent uroflowmetry and urodynamic pressure flow study (PFS) with simultaneous transcutaneous NIRS monitoring. Next, the postvoid residual urine volume was measured using ultrasonography. Data analysis first classified each subject as obstructed or unobstructed using the standard pressure flow data and nomogram and compared these results with the NIRS algorithm, which analyzed the pattern of change of the NIRS data plus the measurements of the postvoid residual urine volume and peak flow rate on uroflowmetry. Results A total of 65 patients were enrolled in the present study. Of these patients, 10 with equivocal PFS findings and 2 with concurrent urinary tract infection were excluded. Of the 53 patients, 29 and 24 were classified as obstructed and unobstructed according to the PFS outcomes, respectively. The International Prostate Symptom Score and uroflowmetry peak flow rate demonstrated significant differences between the obstructed and unobstructed patients. The NIRS algorithm correctly identified 25 patients diagnosed as obstructed (86.2%) and 21 diagnosed as unobstructed (87.5%) according to the PFS findings. Conclusion The NIRS algorithm could be a noninvasive option for the diagnosis of bladder outlet obstruction in men with LUTS, with 86.2% and 87.5% sensitivity and specificity, respectively.