Mr. Licht et al., COMPARISON OF RIGISCAN AND SLEEP LABORATORY NOCTURNAL PENILE TUMESCENCE IN THE DIAGNOSIS OF ORGANIC IMPOTENCE, The Journal of urology, 154(5), 1995, pp. 1740-1743
Purpose: We evaluated the relative use of RigiScan measurement of rad
ial rigidity compared to sleep laboratory measurement of axial rigidit
y and trained observer determination of erectile function in the diagn
osis of organic impotence. Materials and Methods: A total of 28 patien
ts underwent simultaneous 2-night formal sleep laboratory nocturnal pe
nile tumescence and RigiScan monitoring. Standard normal values for ra
dial rigidity and axial rigidity were tested for accuracy in predictin
g normal nocturnal penile tumescence compared to trained observer dete
rmination of the adequacy of an erection for penetration. Results: Rig
iScan tip measurements correlated poorly with buckling pressure, while
base measurements strongly correlated (p = 0.0005). Observer determin
ation of a functional erection was strongly associated with tip (p = 0
.002), base (p = 0.0005) and buckling pressure measurements (p = 0.000
5). Using observer determination as the gold standard receiver operati
ng curves were generated to select RigiScan base and buckling pressure
measurements that predicted functional erections with the highest sen
sitivity and specificity. Conclusions: RigiScan is a useful tool for m
easuring nocturnal penile tumescence. However, base measurements are m
ore accurate than tip measurements for evaluating erectile function. T
he currently accepted level of rigidity used to define a normal erecti
on (70% or greater) overestimates organic erectile dysfunction.