Evaluation of penile erection rigidity in healthy men using virtual touch tissue quantification

BACKGROUND: The aim of the study was to describe the shear wave velocity (SWV) values of the penis by virtual touch tissue quantification (VTTQ) and to examine the clinical usefulness of this procedure in evaluation of the rigidity changes in penile erection. PATIENTS AND METHODS. VTTQ was performed in 37 healthy volunteers. In the course of erection, SWV values of glans penis, corpus penis and radix penis were quantified and grades of erection were documented. The SWV values at different grades of erection were compared. RESULTS: The axial and radial SWV values of glans penis, corpus penis and radix penis all significantly decreased from Grade 0 to Grade 4 of erection. At Grade 4, they were less than one-third of that at Grade 0 (axial direction: 0.79 ± 0.13 vs. 2.79 ± 0.32 for glans penis, P<0.001; 0.77 ± 0.19 vs. 2.84 ± 0.30 for corpus penis, P<0.001 and 0.76 ± 0.15 vs. 2.81 ± 0.34 for radix penis, P<0.001; radial direction: 0.82 ± 0.15 vs. 2.83 ± 0.31 for glans penis, P<0.001; 0.79 ± 0.18 vs. 2.81 ± 0.27 for corpus penis, P<0.001 and 0.81 ± 0.16 vs. 2.82 ± 0.33 for radix penis, P<0.001). CONCLUSIONS: VTTQ can provide numerical measurements of penile rigidity and can effectively and sensitively indicate the axial and radial rigidity changes in penile erection, which provide a new approach to assessing the erectile function.